Enzymes and Their Mechanisms
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Questions and Answers

What happens to the rate of a chemical reaction if an enzyme becomes non-functional?

  • The enzyme can regenerate itself to continue the reaction.
  • The reaction rate remains unchanged.
  • The reaction rate increases significantly.
  • The reaction rate decreases or stops. (correct)

    • What does a lower Km value indicate about an enzyme's affinity for its substrate?

  • The enzyme has a higher affinity. (correct)
  • The enzyme does not require substrate to function.
  • The enzyme has a lower efficiency.
  • The enzyme functions at a slower rate.

    • How do competitive inhibitors affect the Km and Vmax of an enzyme-catalyzed reaction?

  • They increase Km but do not change Vmax. (correct)
  • They increase Km and decrease Vmax.
  • They decrease both Km and Vmax.
  • They decrease Km but do not change Vmax.

    • What is Vmax in the context of enzyme kinetics?

    <p>The maximum rate of an enzyme-catalyzed reaction.</p> Signup and view all the answers

    What effect does temperature have on enzyme activity?

    <p>Higher temperatures can denature enzymes, decreasing activity.</p> Signup and view all the answers

    What does the Induced Fit Model of enzyme action suggest about the shape of the active site?

    <p>The active site changes shape to accommodate the substrate.</p> Signup and view all the answers

    What is meant by absolute specificity of an enzyme?

    <p>An enzyme acts only on a specific substrate.</p> Signup and view all the answers

    How does an increase in temperature generally affect enzyme activity?

    <p>It increases the reaction rate by promoting more collisions.</p> Signup and view all the answers

    What effect does increasing substrate concentration have on enzyme activity, assuming enzyme concentration is constant?

    <p>It will speed up the reaction rate until a saturation point is reached.</p> Signup and view all the answers

    What is the main characteristic of group specificity in enzymes?

    <p>Enzymes will act on substrates that share a specific functional group.</p> Signup and view all the answers

    Which factor can cause enzyme denaturation, potentially leading to loss of function?

    <p>Extreme pH levels.</p> Signup and view all the answers

    What is the effect of increased enzyme concentration on the reaction rate, assuming substrate concentration is constant?

    <p>The reaction rate increases with more enzymes present.</p> Signup and view all the answers

    Which type of specificity allows an enzyme to distinguish between different stereoisomers?

    <p>Stereochemical specificity.</p> Signup and view all the answers

    What is the primary function of ACE inhibitors?

    <p>Inhibit angiotensin-converting enzyme</p> Signup and view all the answers

    What is the role of transpeptidase in bacterial cells?

    <p>Strengthening the cell wall</p> Signup and view all the answers

    Increased levels of which enzyme indicate a myocardial infarction?

    <p>Lactate dehydrogenase</p> Signup and view all the answers

    How does Tissue plasminogen activator (TPA) function in the treatment of myocardial infarction?

    <p>It activates the enzyme that dissolves blood clots</p> Signup and view all the answers

    Which drug acts on dihydrofolate reductase for cancer treatment?

    <p>Methotrexate</p> Signup and view all the answers

    Which enzyme plays a key role in purine metabolism that can be inhibited by Allopurinol?

    <p>Xanthine oxidase</p> Signup and view all the answers

    What is the effect of temperature on enzyme activity?

    <p>Enzymes denature at very high temperatures</p> Signup and view all the answers

    Which factor does NOT affect the specificity of an enzyme?

    <p>Overall temperature of the environment</p> Signup and view all the answers

    Which of the following statements accurately describes the Michaelis-Menten kinetics?

    <p>The rate of reaction becomes independent of substrate concentration at high levels</p> Signup and view all the answers

    What does the induced fit model of enzymes describe?

    <p>Enzymes change shape to fit the substrate perfectly.</p> Signup and view all the answers

    Which factor does NOT affect enzyme specificity?

    <p>The concentration of substrates</p> Signup and view all the answers

    How does an increase in temperature generally affect enzyme activity?

    <p>Enzyme activity decreases above a certain temperature.</p> Signup and view all the answers

    What is the primary function of an enzyme?

    <p>To catalyze chemical reactions</p> Signup and view all the answers

    What are the key components of Michaelis-Menten kinetics?

    <p>The rate of reaction is directly proportional to substrate concentration.</p> Signup and view all the answers

    Which of the following factors does NOT typically affect enzyme activity?

    <p>Lighting conditions</p> Signup and view all the answers

    Which statement best describes enzyme specificity?

    <p>Enzymes have active sites that precisely fit their substrates.</p> Signup and view all the answers

    How does temperature generally affect enzyme activity?

    <p>Too high temperatures can denature enzymes.</p> Signup and view all the answers

    Which of the following enzymes catalyze redox reactions?

    <p>Oxidase</p> Signup and view all the answers

    What role do hydrolases play in biochemical reactions?

    <p>Facilitating hydrolysis of various bonds</p> Signup and view all the answers

    What does the Michaelis-Menten equation describe?

    <p>The kinetics of enzyme-substrate interactions.</p> Signup and view all the answers

    Which enzymes are involved in the removal of a phosphate group?

    <p>Phosphatases</p> Signup and view all the answers

    Which factor does NOT affect enzyme activity?

    <p>Atmospheric pressure</p> Signup and view all the answers

    Which statement about enzyme concentration and reaction rate is correct?

    <p>Reaction rate is independent of enzyme concentration above saturation point.</p> Signup and view all the answers

    What is the name for the protein part of a conjugated enzyme?

    <p>Apoenzyme</p> Signup and view all the answers

    Which of the following describes isomerases?

    <p>They cause isomerization changes within a single molecule.</p> Signup and view all the answers

    What type of molecules can serve as coenzymes?

    <p>Small organic molecules</p> Signup and view all the answers

    What is the term for the specific region of an enzyme where substrate binds?

    <p>Active site</p> Signup and view all the answers

    Which characteristic of enzymes allows them to accelerate reactions without being consumed?

    <p>Catalytic mechanism</p> Signup and view all the answers

    Why must enzymes be used in small quantities?

    <p>Because they have enormous catalytic power</p> Signup and view all the answers

    What happens to the Vmax of an enzyme when it is affected by a noncompetitive inhibitor?

    <p>Vmax decreases</p> Signup and view all the answers

    How does an uncompetitive inhibitor affect both Vmax and Km?

    <p>Decreases both Vmax and Km</p> Signup and view all the answers

    What is the function of an allosteric site on an enzyme?

    <p>It provides a regulatory site for effector molecules</p> Signup and view all the answers

    What distinguishes positive allosteric regulation from negative allosteric regulation?

    <p>Positive regulation increases enzyme activity, while negative decreases it</p> Signup and view all the answers

    What defining characteristic of uncompetitive inhibitors impacts their reversal by substrate concentration?

    <p>They cannot be reversed by increasing substrate concentration</p> Signup and view all the answers

    What is the primary role of enzymes in biological reactions?

    <p>To accelerate the reaction without being consumed</p> Signup and view all the answers

    Which property differentiates enzymes from regular catalysts?

    <p>Enzymes exhibit high specificity for substrates</p> Signup and view all the answers

    What is an active site?

    <p>The portion of an enzyme where catalysis occurs</p> Signup and view all the answers

    What does the term 'holoenzyme' refer to?

    <p>The complete, active enzyme including its cofactor</p> Signup and view all the answers

    Why are enzymes typically required in only small quantities?

    <p>They can continuously catalyze reactions</p> Signup and view all the answers

    What defines the specificity of an enzyme?

    <p>The shape and structure of the enzyme</p> Signup and view all the answers

    What is the role of a coenzyme?

    <p>To serve as a non-protein part of a conjugated enzyme</p> Signup and view all the answers

    Which statement accurately describes how enzymes affect chemical reactions?

    <p>Enzymes lower the activation energy required</p> Signup and view all the answers

    Which suffix is commonly used for digestive enzymes?

    <p>-in</p> Signup and view all the answers

    What type of enzyme catalyzes oxidation or reduction reactions?

    <p>Oxidoreductases</p> Signup and view all the answers

    Which of the following enzymes is responsible for hydrolyzing ester linkages in lipids?

    <p>Lipase</p> Signup and view all the answers

    Which class of enzymes is known for transferring functional groups between molecules?

    <p>Transferases</p> Signup and view all the answers

    What is the primary biochemical activity of lyases?

    <p>Cleave bonds without hydrolysis</p> Signup and view all the answers

    Which enzyme is an example of a dehydratase?

    <p>Deaminase</p> Signup and view all the answers

    Which class of enzymes is responsible for catalyzing isomerization changes?

    <p>Isomerases</p> Signup and view all the answers

    What type of reaction does an oxidase enzyme catalyze?

    <p>Oxidation of substrate</p> Signup and view all the answers

    Which reaction is facilitated by a kinase enzyme?

    <p>Transfer of a phosphate group</p> Signup and view all the answers

    Which enzyme is used for the hydrolysis of glycosidic bonds in carbohydrates?

    <p>Carbohydrase</p> Signup and view all the answers

    What is the primary role of ligases in biochemical reactions?

    <p>To join two molecules using energy from ATP</p> Signup and view all the answers

    Which model of enzyme action proposes that the active site is rigid and does not change shape?

    <p>Lock &amp; Key Model</p> Signup and view all the answers

    What does absolute specificity mean in the context of enzymes?

    <p>An enzyme will only catalyze a reaction for a specific substrate</p> Signup and view all the answers

    Which statement best describes the effect of increased temperature on enzyme kinetics?

    <p>Enzyme kinetics increases due to more molecular collisions</p> Signup and view all the answers

    How does the pH level affect enzyme activity?

    <p>Small pH changes can cause enzyme denaturation</p> Signup and view all the answers

    What happens to enzyme activity when substrate concentration is increased while enzyme concentration is kept constant?

    <p>The reaction rate reaches a saturation point</p> Signup and view all the answers

    Which type of specificity allows an enzyme to act on different substrates with similar functional groups?

    <p>Group Specificity</p> Signup and view all the answers

    What kind of change occurs in the enzyme's active site during the induced fit model?

    <p>It undergoes a conformational change to better bind the substrate</p> Signup and view all the answers

    Which enzyme specificity distinguishes between different stereoisomers?

    <p>Stereochemical Specificity</p> Signup and view all the answers

    What is the effect of increasing enzyme concentration while keeping substrate concentration constant?

    <p>Reaction rate increases proportionally with enzyme concentration</p> Signup and view all the answers

    What would be the expected outcome if an enzyme is no longer functional?

    <p>The chemical reaction will cease or be greatly diminished.</p> Signup and view all the answers

    How does a competitive inhibitor affect the apparent Km value of an enzyme-catalyzed reaction?

    <p>It increases the Km value, indicating a lower affinity for substrate.</p> Signup and view all the answers

    What does Vmax represent in enzyme kinetics?

    <p>The highest rate of an enzyme-catalyzed reaction at saturation.</p> Signup and view all the answers

    What characterizes a reversible non-competitive inhibitor?

    <p>It can bind to both enzyme and enzyme-substrate complex.</p> Signup and view all the answers

    Which statement regarding competitive inhibition is true?

    <p>The effects of competitive inhibition can be mitigated by increasing substrate concentration.</p> Signup and view all the answers

    Which parameters are used in the Michaelis-Menten equation?

    <p>Substrate concentration and reaction rate.</p> Signup and view all the answers

    What does a higher Km value indicate about an enzyme's affinity for its substrate?

    <p>It demonstrates a lower affinity for the substrate.</p> Signup and view all the answers

    In the context of enzyme function, what is enzyme inhibition?

    <p>A substance that slows down or halts the enzyme's catalytic function.</p> Signup and view all the answers

    What is the significance of the Lineweaver-Burke plot in understanding enzyme kinetics?

    <p>It allows visualization of enzyme kinetics through linear plotting of reaction rates.</p> Signup and view all the answers

    What does a lower Km value signify about an enzyme's performance?

    <p>There is a high affinity for its substrate, facilitating rapid reaction rates.</p> Signup and view all the answers

    What suffix is commonly associated with digestive enzymes?

    <p>-ase and -in</p> Signup and view all the answers

    Which of the following classes of enzymes is responsible for catalyzing oxidation and reduction reactions?

    <p>Oxidoreductases</p> Signup and view all the answers

    What type of reaction do transferases typically catalyze?

    <p>Transfer of functional groups</p> Signup and view all the answers

    Which enzyme class specifically catalyzes the hydrolysis of bonds?

    <p>Hydrolases</p> Signup and view all the answers

    What is the main function of isomerases?

    <p>Catalyze isomerization changes</p> Signup and view all the answers

    Which of the following is an example of a lyase?

    <p>Deaminase</p> Signup and view all the answers

    What type of enzyme is most likely to catalyze the removal of water from a substrate?

    <p>Lyase</p> Signup and view all the answers

    What is the primary biochemical activity of oxidoreductases?

    <p>To facilitate oxidation/reduction reactions</p> Signup and view all the answers

    What is the primary mechanism by which penicillin functions to kill bacteria?

    <p>Inhibiting transpeptidase enzyme activity</p> Signup and view all the answers

    What is the role of lactate dehydrogenase (LDH) in diagnosing a myocardial infarction?

    <p>It is released from damaged heart tissue</p> Signup and view all the answers

    Which drug is known for activating the enzyme plasminogen to dissolve blood clots?

    <p>Streptokinase</p> Signup and view all the answers

    Which of the following drugs targets xanthine oxidase to treat hyperuricemia?

    <p>Allopurinol</p> Signup and view all the answers

    Which enzyme is targeted by antifolates for cancer treatment?

    <p>Dihydrofolate reductase</p> Signup and view all the answers

    What effect does competitive inhibition have on the apparent Km of an enzyme-catalyzed reaction?

    <p>It increases the Km value.</p> Signup and view all the answers

    In the context of enzyme kinetics, what does Vmax represent?

    <p>The maximum rate of enzyme-catalyzed reaction.</p> Signup and view all the answers

    How does a lower Km value relate to an enzyme's affinity for its substrate?

    <p>It indicates a higher affinity for the substrate.</p> Signup and view all the answers

    What type of inhibition binds irreversibly to the enzyme's active site?

    <p>Irreversible inhibition</p> Signup and view all the answers

    Which statement about competitive inhibitors is true?

    <p>They can be overcome by increasing substrate concentration.</p> Signup and view all the answers

    What happens to the reaction rate if an enzyme is non-functional?

    <p>The reaction rate decreases substantially.</p> Signup and view all the answers

    Which of the following describes the significance of Km in enzyme kinetics?

    <p>It reflects the affinity of the enzyme for its substrate.</p> Signup and view all the answers

    Which scenario would not lead to increased enzyme activity?

    <p>Decreasing the temperature to sub-optimal levels.</p> Signup and view all the answers

    What characteristic of competitive inhibitors differentiates them from irreversible inhibitors?

    <p>They can be reversed by increasing substrate concentration.</p> Signup and view all the answers

    In a Lineweaver-Burke plot for competitive inhibition, what changes are expected?

    <p>Km appears increased while Vmax remains unchanged.</p> Signup and view all the answers

    What is the primary function of ligases in biochemical reactions?

    <p>To join two molecules with covalent bonds using ATP</p> Signup and view all the answers

    What does the lock and key model of enzyme action imply about the active site?

    <p>The active site has a fixed structure that only fits a specific substrate</p> Signup and view all the answers

    Which type of enzyme specificity allows for distinguishing between different stereoisomers?

    <p>Stereochemical specificity</p> Signup and view all the answers

    How does an increase in temperature generally affect enzymes up to a certain point?

    <p>It increases the rate of reaction due to more collisions</p> Signup and view all the answers

    What is observed when substrate concentration is increased while enzyme concentration is held constant?

    <p>The reaction rate increases until a saturation point is reached</p> Signup and view all the answers

    What happens to enzymes when pH levels deviate significantly from their optimal range?

    <p>They may denature and lose their function</p> Signup and view all the answers

    What aspect of enzyme specificity is characterized by an enzyme acting only on similar substrates with a specific functional group?

    <p>Group specificity</p> Signup and view all the answers

    What will likely happen to enzyme activity if the enzyme concentration is increased while substrate concentration remains constant?

    <p>The reaction rate will increase</p> Signup and view all the answers

    In the induced fit model, how does the active site interact with the substrate?

    <p>The active site changes shape to fit around the substrate</p> Signup and view all the answers

    Which type of specificity is illustrated by an enzyme that catalyzes hydrolysis of peptide bonds regardless of the rest of the molecular structure?

    <p>Linkage specificity</p> Signup and view all the answers

    What effect do uncompetitive inhibitors have on both Vmax and Km?

    <p>Decrease both Vmax and Km</p> Signup and view all the answers

    How does the presence of a noncompetitive inhibitor affect the enzyme-substrate complex?

    <p>It decreases the enzyme-substrate complex leading to a lower Vmax</p> Signup and view all the answers

    Which of the following statements about competitive inhibitors is true?

    <p>They can be reversed by increasing substrate concentration</p> Signup and view all the answers

    What defines negative allosteric regulation?

    <p>It decreases the enzyme's affinity for the substrate</p> Signup and view all the answers

    What is the primary role of an allosteric site on an enzyme?

    <p>To regulate enzyme activity through effector binding</p> Signup and view all the answers

    Which statement correctly describes binding in allosteric regulation?

    <p>Positive effectors always increase substrate binding affinity</p> Signup and view all the answers

    How do uncompetitive inhibitors uniquely interact with enzyme kinetics?

    <p>They bind exclusively to enzyme-substrate complexes</p> Signup and view all the answers

    What distinguishes competitive inhibition from other types of inhibition concerning Km?

    <p>It increases Km while Vmax remains unchanged</p> Signup and view all the answers

    In which scenario will an allosteric site lead to a decrease in enzyme activity?

    <p>When a negative allosteric effector binds</p> Signup and view all the answers

    What does the presence of differing y-intercepts on a Lineweaver-Burke plot indicate in the case of noncompetitive inhibition?

    <p>Vmax decreases while Km remains unchanged</p> Signup and view all the answers

    What is the mechanism by which penicillin acts on bacteria?

    <p>Inhibits the enzyme transpeptidase</p> Signup and view all the answers

    What condition may be suggested by elevated levels of lactate dehydrogenase (LDH) in blood tests?

    <p>Myocardial infarction</p> Signup and view all the answers

    Which drug targets the enzyme xanthine oxidase?

    <p>Allopurinol</p> Signup and view all the answers

    Which enzyme is activated by tissue plasminogen activator (TPA) to dissolve blood clots?

    <p>Plasminogen</p> Signup and view all the answers

    Which enzyme is used in the treatment of acute lymphocytic leukemia?

    <p>Asparaginase</p> Signup and view all the answers

    What is the primary function of enzymes in biological reactions?

    <p>To speed up the reaction rate</p> Signup and view all the answers

    Which statement accurately describes the active site of an enzyme?

    <p>It provides optimal conditions for substrate conversion.</p> Signup and view all the answers

    Which of the following is a characteristic of enzymes?

    <p>They are highly specific for their substrates.</p> Signup and view all the answers

    What are ribozymes?

    <p>RNA molecules with catalytic properties.</p> Signup and view all the answers

    What is the significance of the coenzyme in a holoenzyme?

    <p>It serves as a non-protein part that aids in enzymatic function.</p> Signup and view all the answers

    Why are enzymes considered catalysts in biological reactions?

    <p>They speed up reactions without being altered.</p> Signup and view all the answers

    What role do R-groups of amino acids play in enzymes?

    <p>They create the unique shape of the active site.</p> Signup and view all the answers

    What term is used to describe the protein part of a conjugated enzyme?

    <p>Apoenzyme</p> Signup and view all the answers

    Which of the following enzymes are classified as oxidoreductases?

    <p>Dehydrogenase</p> Signup and view all the answers

    What is the primary biochemical activity of hydrolases?

    <p>Catalyze the hydrolysis of various bonds</p> Signup and view all the answers

    Which class of enzymes is responsible for adding or removing functional groups from substrates?

    <p>Transferases</p> Signup and view all the answers

    What defines the nomenclature of enzymes?

    <p>They are named based on the type of reaction they catalyze and/or their substrate.</p> Signup and view all the answers

    Which enzyme is known for the hydrolysis of ester linkages in lipids?

    <p>Lipase</p> Signup and view all the answers

    What type of reaction do lyases catalyze?

    <p>Cleave bonds through means other than hydrolysis and oxidation</p> Signup and view all the answers

    Which enzyme class would include kinases?

    <p>Transferases</p> Signup and view all the answers

    Which type of enzyme is involved in the removal of ammonia (NH3) from a substrate?

    <p>Deaminases</p> Signup and view all the answers

    What is the main function of isomerases in biochemical activity?

    <p>Catalyze isomerization changes within a single molecule</p> Signup and view all the answers

    Which suffix is commonly associated with digestive enzymes?

    <p>-ase</p> Signup and view all the answers

    What effect does competitive inhibition have on the maximum rate of an enzyme-catalyzed reaction?

    <p>It has no effect on Vmax.</p> Signup and view all the answers

    Which value indicates a higher affinity of an enzyme for its substrate?

    <p>Low Km</p> Signup and view all the answers

    Which type of inhibition involves a substance that binds to the active site of an enzyme?

    <p>Reversible competitive inhibition</p> Signup and view all the answers

    What does an increased Km value signify in the presence of a competitive inhibitor?

    <p>Decreased affinity for the substrate</p> Signup and view all the answers

    What is the primary characteristic of reversible non-competitive inhibition?

    <p>It binds to the enzyme-substrate complex.</p> Signup and view all the answers

    What does Vmax represent in the context of enzyme kinetics?

    <p>The highest rate of product formation achievable.</p> Signup and view all the answers

    What defines an irreversible inhibitor?

    <p>It permanently alters the enzyme structure.</p> Signup and view all the answers

    In the context of enzyme inhibition, what does 'turnover number' refer to?

    <p>The number of substrate molecules converted to product per unit time.</p> Signup and view all the answers

    What is typically true of both competitive and non-competitive inhibition?

    <p>Both result in the same reaction velocity at saturation.</p> Signup and view all the answers

    Which characteristic is specific to competitive inhibition compared to non-competitive inhibition?

    <p>It can be reversed by increasing the concentration of substrate.</p> Signup and view all the answers

    What effect do noncompetitive inhibitors have on Vmax and Km?

    <p>Vmax decreases, Km remains unchanged</p> Signup and view all the answers

    What characteristic is true for uncompetitive inhibition?

    <p>It decreases both Vmax and Km</p> Signup and view all the answers

    How does positive allosteric regulation affect enzyme activity?

    <p>It increases the enzyme's affinity for the substrate</p> Signup and view all the answers

    What is the role of an allosteric site on an enzyme?

    <p>It provides a binding site for regulatory molecules</p> Signup and view all the answers

    What type of Lineweaver-Burk plot is observed in uncompetitive inhibition?

    <p>Parallel lines for uninhibited and inhibited reactions</p> Signup and view all the answers

    What happens to Km in the presence of a noncompetitive inhibitor?

    <p>Km is unaffected</p> Signup and view all the answers

    Which statement accurately describes negative allosteric regulation?

    <p>It decreases the enzyme's affinity for its substrate</p> Signup and view all the answers

    Which of the following is a characteristic of competitive inhibitors?

    <p>They can be overcome by increasing substrate concentration</p> Signup and view all the answers

    For uncompetitive inhibition, what is the effect of the inhibitor?

    <p>It binds to the enzyme-substrate complex</p> Signup and view all the answers

    Which characteristic differentiates uncompetitive inhibition from other forms of inhibition?

    <p>It decreases both Vmax and Km simultaneously</p> Signup and view all the answers

    What therapeutic application does Streptokinase serve?

    <p>Clot lysis in myocardial infarction</p> Signup and view all the answers

    Which enzyme is targeted by antifolates like methotrexate in cancer treatment?

    <p>Dihydrofolate reductase</p> Signup and view all the answers

    What is the primary role of lactate dehydrogenase (LDH) in the context of myocardial infarction?

    <p>To indicate increased cellular damage</p> Signup and view all the answers

    Which enzyme does TPA activate to facilitate the dissolution of blood clots?

    <p>Plasminogen</p> Signup and view all the answers

    Which of the following drugs inhibits the enzyme xanthine oxidase and is used for treating gout?

    <p>Allopurinol</p> Signup and view all the answers

    What indicates that enzymes are not consumed during chemical reactions?

    <p>They remain unchanged after the reaction.</p> Signup and view all the answers

    What defines the specificity of an enzyme?

    <p>The chemical properties of the enzyme's active site.</p> Signup and view all the answers

    Which statement accurately describes the properties of enzymes?

    <p>They have enormous catalytic power but remain unchanged.</p> Signup and view all the answers

    How do active sites of enzymes contribute to their function?

    <p>By offering optimal conditions for substrate conversion.</p> Signup and view all the answers

    What are ribozymes characterized by?

    <p>They are RNA molecules that act as enzymes.</p> Signup and view all the answers

    Which component of a conjugated enzyme is responsible for enhancing its activity?

    <p>Coenzyme.</p> Signup and view all the answers

    Which class of enzymes is responsible for catalyzing redox reactions?

    <p>Oxidoreductases</p> Signup and view all the answers

    What is the role of the active site in an enzyme's function?

    <p>To provide a specific region for substrate binding.</p> Signup and view all the answers

    What type of reaction do hydrolases catalyze?

    <p>Hydrolysis of bonds</p> Signup and view all the answers

    Which enzyme is involved in the transfer of phosphate groups?

    <p>Kinase</p> Signup and view all the answers

    What distinguishes the apoenzyme from other enzyme components?

    <p>It is the protein part of a conjugated enzyme.</p> Signup and view all the answers

    What is the primary activity of lyases?

    <p>Cleave various bonds without hydrolysis</p> Signup and view all the answers

    Which enzyme is classified under transferases?

    <p>Transaminase</p> Signup and view all the answers

    What describes the function of isomerases?

    <p>Catalyze isomerization changes</p> Signup and view all the answers

    Which of the following enzymes is specifically associated with hydrolyzing ester linkages?

    <p>Lipase</p> Signup and view all the answers

    Which enzyme class includes pepsin and chymotrypsin?

    <p>Hydrolases</p> Signup and view all the answers

    What is a common feature of dehydratases?

    <p>They remove water from substrates.</p> Signup and view all the answers

    Which term refers to enzymes like oxidase and reductase?

    <p>Oxidoreductases</p> Signup and view all the answers

    Which type of enzyme specificity allows an enzyme to act only on a particular type of chemical bond, regardless of the rest of the molecular structure?

    <p>Linkage specificity</p> Signup and view all the answers

    What is the primary distinction between the Lock & Key Model and the Induced Fit Model of enzyme action?

    <p>The Induced Fit Model involves conformational change of the enzyme.</p> Signup and view all the answers

    How does temperature specifically affect enzyme kinetics within physiological ranges?

    <p>Temperature increase raises enzyme activity until denaturation occurs.</p> Signup and view all the answers

    Which factor regarding substrate concentration is true for enzyme-catalyzed reactions?

    <p>Reaction rates remain constant despite changes in substrate concentration after saturation.</p> Signup and view all the answers

    What characterizes absolute specificity in enzymes?

    <p>An enzyme can catalyze reactions for only one specific substrate.</p> Signup and view all the answers

    In which situation would an enzyme likely experience denaturation due to pH changes?

    <p>With significant deviations from the characteristic pH range for that enzyme.</p> Signup and view all the answers

    Which of the following statements correctly describes the enzyme-substrate complex?

    <p>It temporarily binds, allowing for faster conversion of substrate to product.</p> Signup and view all the answers

    Which enzyme specificity is exemplified by enzymes acting on similar substrates that share a specific functional group?

    <p>Group specificity</p> Signup and view all the answers

    What is the primary outcome of increased enzyme concentration in reactions where the substrate concentration is held constant?

    <p>The reaction rate increases with more enzyme present.</p> Signup and view all the answers

    What characteristic distinguishes noncompetitive inhibitors from other types of enzyme inhibitors?

    <p>Decrease Vmax without affecting Km</p> Signup and view all the answers

    In the context of uncompetitive inhibition, how does the inhibitor affect the enzyme kinetics?

    <p>Vmax and Km both decrease</p> Signup and view all the answers

    What is the key mechanism of action for allosteric inhibitors?

    <p>They bind to an allosteric site and alter enzyme activity</p> Signup and view all the answers

    Which statement best explains the concept of positive allosteric regulation?

    <p>It increases the enzyme's substrate binding ability</p> Signup and view all the answers

    What is the effect of noncompetitive inhibition on the Lineweaver-Burk plot compared to a control reaction?

    <p>The y-intercepts are the same for both lines</p> Signup and view all the answers

    What distinguishes negative allosteric regulation from uncompetitive inhibition?

    <p>Uncompetitive inhibition affects the enzyme-substrate complex</p> Signup and view all the answers

    How does an uncompetitive inhibitor affect the enzyme's ability to convert substrate into product?

    <p>It decreases the turnover number of the enzyme</p> Signup and view all the answers

    Which of the following best describes competitive inhibition?

    <p>It decreases Vmax without affecting Km</p> Signup and view all the answers

    Which property indicates that an enzyme can be regulated by allosteric effectors?

    <p>Presence of a regulatory site distinct from the active site</p> Signup and view all the answers

    What role does an allosteric site play in enzyme function?

    <p>It allows for the binding of non-substrate molecules that modulate activity</p> Signup and view all the answers

    Which enzyme's inhibition is specifically responsible for the bactericidal effect of Penicillins?

    <p>Transpeptidase</p> Signup and view all the answers

    What is the main therapeutic application of Tissue plasminogen activator (TPA)?

    <p>Dissolving blood clots in myocardial infarction</p> Signup and view all the answers

    Which drug targets xanthine oxidase to manage a specific condition?

    <p>Allopurinol</p> Signup and view all the answers

    Which enzyme's activity is suggested to indicate a myocardial infarction when present in elevated blood levels?

    <p>Lactate dehydrogenase</p> Signup and view all the answers

    For which condition is Asparaginase primarily used as a treatment?

    <p>Acute lymphocytic leukemia</p> Signup and view all the answers

    What primarily determines the specificity of enzymes for their substrates?

    <p>The shape and structure of the active site</p> Signup and view all the answers

    Which statement about enzymes is NOT true?

    <p>Enzymes alter the equilibrium of a reaction.</p> Signup and view all the answers

    What is the term for the combination of an apoenzyme and its cofactor?

    <p>Holoenzyme</p> Signup and view all the answers

    Which of the following correctly describes ribozymes?

    <p>They are specialized RNA molecules that act as enzymes.</p> Signup and view all the answers

    What is the role of the active site on an enzyme?

    <p>It is where substrates bind and reactions are catalyzed.</p> Signup and view all the answers

    What is the significance of enzymes being considered biocatalysts?

    <p>They increase reaction rates without being consumed.</p> Signup and view all the answers

    How do enzymes facilitate chemical reactions?

    <p>By providing optimal conditions in their active sites</p> Signup and view all the answers

    Which property of enzymes allows for their substantial catalytic power?

    <p>Their three-dimensional globular structure</p> Signup and view all the answers

    What is indicated by a higher Km value for an enzyme?

    <p>Lower substrate affinity</p> Signup and view all the answers

    If a competitive inhibitor is introduced to an enzyme reaction, which of the following statements is true?

    <p>Vmax remains unchanged while Km increases.</p> Signup and view all the answers

    What happens to the turnover number of an enzyme if it becomes non-functional?

    <p>It decreases to zero.</p> Signup and view all the answers

    How do reversible non-competitive inhibitors affect enzyme activity?

    <p>They decrease Vmax but do not change Km.</p> Signup and view all the answers

    Which parameter in the Michaelis-Menten equation reflects the maximum rate of an enzyme-catalyzed reaction?

    <p>Vmax</p> Signup and view all the answers

    In competitive inhibition, increasing the substrate concentration can overcome the inhibitor's effect. Why is this?

    <p>Higher substrate concentration can outcompete the inhibitor for binding.</p> Signup and view all the answers

    What type of inhibition is characterized by a substance permanently binding to an enzyme, leading to a loss of activity?

    <p>Irreversible inhibition</p> Signup and view all the answers

    What does Vmax tell you about an enzyme's performance under substrate saturation conditions?

    <p>It represents the capacity for substrate conversion to product.</p> Signup and view all the answers

    Why is Km considered an important measure in enzyme kinetics?

    <p>It reflects the enzyme's affinity for its substrate.</p> Signup and view all the answers

    What role does the Lineweaver-Burke plot play in understanding competitive inhibition?

    <p>It allows for the determination of Km and Vmax from double reciprocal plots.</p> Signup and view all the answers

    What is the primary effect of noncompetitive inhibitors on enzyme kinetics?

    <p>Decrease Vmax but do not change Km</p> Signup and view all the answers

    How do uncompetitive inhibitors affect enzyme kinetics on a Lineweaver-Burk plot?

    <p>They produce parallel lines for inhibited and uninhibited reactions</p> Signup and view all the answers

    What characterizes positive allosteric regulation of enzymes?

    <p>Increases the enzyme's affinity for the substrate</p> Signup and view all the answers

    Which statement is true regarding the characteristics of allosteric enzymes?

    <p>They can exhibit sigmoidal kinetics.</p> Signup and view all the answers

    In the context of competitive inhibitors, which statement is accurate?

    <p>They can be overcome by increasing the substrate concentration.</p> Signup and view all the answers

    Which describes the mechanism of uncompetitive inhibition?

    <p>Inhibitor binds to the enzyme-substrate complex, preventing product formation.</p> Signup and view all the answers

    How does negative allosteric regulation affect enzyme activity?

    <p>It decreases the enzyme's catalytic efficiency.</p> Signup and view all the answers

    What is the defining feature of the allosteric site on an enzyme?

    <p>It serves as a regulatory site for effector molecules.</p> Signup and view all the answers

    What is the result of a noncompetitive inhibitor on the enzyme-substrate complex?

    <p>It decreases the amount of enzyme-substrate complex available for product formation.</p> Signup and view all the answers

    What role does the allosteric site serve in enzyme function?

    <p>It allows for feedback inhibition to regulate enzyme activity.</p> Signup and view all the answers

    Which type of enzyme specificity is exhibited by catalase?

    <p>Absolute Specificity</p> Signup and view all the answers

    In the Induced Fit Model, what occurs when the substrate binds to the enzyme?

    <p>The active site changes shape to accommodate the substrate.</p> Signup and view all the answers

    What happens to enzyme activity when temperature increases within the optimal range?

    <p>Enzyme kinetics increases due to more collisions.</p> Signup and view all the answers

    Which specificity allows an enzyme to act on similar substrates with specific functional groups?

    <p>Group Specificity</p> Signup and view all the answers

    What defines the saturation point of an enzyme-catalyzed reaction?

    <p>The reaction rate reaches a maximum despite further increases in substrate concentration.</p> Signup and view all the answers

    What characteristic pH range is most conducive for enzyme activity?

    <p>A narrow range specific to each enzyme</p> Signup and view all the answers

    Which type of bonds are specifically hydrolyzed by phosphatases?

    <p>Phosphate-ester bonds</p> Signup and view all the answers

    How does increased enzyme concentration affect reaction rates with a constant substrate concentration?

    <p>It increases the reaction rate.</p> Signup and view all the answers

    What is a key factor in enzyme specificity that allows them to differentiate between stereoisomers?

    <p>Chirality of the active site</p> Signup and view all the answers

    What is the role of synthetases in biochemical reactions?

    <p>To form new bonds between substrates utilizing ATP.</p> Signup and view all the answers

    What is the mechanism by which Penicillin exerts its antibiotic effect?

    <p>Inhibiting transpeptidase enzyme activity</p> Signup and view all the answers

    In which condition is Tissue plasminogen activator (TPA) most effectively used?

    <p>Myocardial infarction</p> Signup and view all the answers

    Which drug is designed to target xanthine oxidase for treating a specific condition?

    <p>Allopurinol</p> Signup and view all the answers

    What condition is associated with increased levels of lactate dehydrogenase (LDH) in the blood?

    <p>Myocardial infarction</p> Signup and view all the answers

    Which enzyme is inhibited by antifolates in cancer therapy?

    <p>Dihydrofolate reductase</p> Signup and view all the answers

    Which statement accurately describes the roles of coenzymes in enzymatic reactions?

    <p>They enhance the activity of enzymes but are not consumed.</p> Signup and view all the answers

    What is the significance of the active site in enzyme function?

    <p>It is the site where substrates are converted into products under optimal conditions.</p> Signup and view all the answers

    Which of the following best describes the term 'apoenzyme'?

    <p>The protein part of an enzyme that becomes inactive when not bound to cofactors.</p> Signup and view all the answers

    Which characteristic of enzymes allows them to demonstrate high specificity for substrates?

    <p>The unique shape and charge of the active site.</p> Signup and view all the answers

    Which factor does NOT generally influence the catalytic power of enzymes?

    <p>The duration of the reaction.</p> Signup and view all the answers

    What distinguishes ribozymes from traditional enzymes?

    <p>Ribozymes are RNA molecules that catalyze reactions.</p> Signup and view all the answers

    Which statement best describes the relationship between enzymes and activation energy?

    <p>Enzymes decrease the activation energy needed to start reactions.</p> Signup and view all the answers

    How does the presence of enzymes affect the equilibrium of a reaction?

    <p>Enzymes accelerate the reach of equilibrium without affecting its position.</p> Signup and view all the answers

    Which class of enzymes is responsible for catalyzing redox reactions?

    <p>Oxidoreductases</p> Signup and view all the answers

    What is the primary function of transferases?

    <p>Transfer functional groups between molecules</p> Signup and view all the answers

    Which suffix is commonly used for enzymes that catalyze the hydrolysis of connections in proteins?

    <p>-ase</p> Signup and view all the answers

    Which enzyme class includes enzymes like lipase and nuclease?

    <p>Hydrolases</p> Signup and view all the answers

    Which of the following enzymes would catalyze the removal of ammonia from a substrate?

    <p>Deaminase</p> Signup and view all the answers

    The term 'mutase' refers to which type of enzyme activity?

    <p>Shifting of chemical groups within a molecule</p> Signup and view all the answers

    Which of the following correctly describes lyases in biochemical reactions?

    <p>They remove elements to produce double bonds.</p> Signup and view all the answers

    What type of biochemical reaction do oxidases facilitate?

    <p>Oxidation of substrates</p> Signup and view all the answers

    Which option denotes the enzyme activity associated with the prefix 'chymo-'?

    <p>Hydrolysis of amide linkages</p> Signup and view all the answers

    Which class of enzymes would you expect to perform isomerization changes within a molecule?

    <p>Isomerases</p> Signup and view all the answers

    What effect does a competitive inhibitor have on the rate of an enzyme-catalyzed reaction when substrate concentration is increased?

    <p>It can be overcome by increasing substrate concentration.</p> Signup and view all the answers

    What does an increased Km value indicate about an enzyme's interaction with its substrate in the presence of a competitive inhibitor?

    <p>The enzyme has lower affinity for the substrate.</p> Signup and view all the answers

    Which statement is true regarding the Vmax of an enzyme-catalyzed reaction when subjected to competitive inhibition?

    <p>Vmax is unchanged.</p> Signup and view all the answers

    In the context of enzyme kinetics, what aspect of the Michaelis-Menten equation is not affected by a competitive inhibitor?

    <p>The maximum reaction velocity (Vmax).</p> Signup and view all the answers

    What is one result of an enzyme becoming non-functional due to denaturation?

    <p>The rate of reaction decreases significantly.</p> Signup and view all the answers

    How does an uncompetitive inhibitor affect the enzyme kinetics?

    <p>Decreases both Km and Vmax</p> Signup and view all the answers

    Which of the following best describes irreversible inhibition of an enzyme?

    <p>It permanently alters the enzyme's structure.</p> Signup and view all the answers

    How does a lower Km value affect the rate of an enzymatic reaction?

    <p>It indicates a requirement for less substrate to achieve maximum velocity.</p> Signup and view all the answers

    What is the main impact of a noncompetitive inhibitor on an enzyme reaction?

    <p>Decreases Vmax while Km remains unchanged</p> Signup and view all the answers

    What is the effect of positive allosteric regulation on enzyme activity?

    <p>Increases substrate affinity and activity</p> Signup and view all the answers

    In the context of the Michaelis-Menten kinetics, what does Vmax represent?

    <p>The rate at which substrate is converted to product under optimal conditions.</p> Signup and view all the answers

    What characterizes the lines produced in a Lineweaver-Burk plot for uncompetitive inhibition?

    <p>They produce parallel lines</p> Signup and view all the answers

    Which of the following statements is true regarding reversible non-competitive inhibition?

    <p>It decreases Vmax but not Km.</p> Signup and view all the answers

    What is the primary site for effector molecules to bind in an allosteric enzyme?

    <p>Regulatory site</p> Signup and view all the answers

    What does the Lineweaver-Burke plot illustrate about enzyme kinetics?

    <p>It represents the reciprocal of reaction rate versus the reciprocal of substrate concentration.</p> Signup and view all the answers

    Why does Km remain unchanged in the presence of a noncompetitive inhibitor?

    <p>Substrate can still bind to the enzyme</p> Signup and view all the answers

    What distinguishes negative allosteric regulation from other enzyme regulatory mechanisms?

    <p>It decreases the enzyme's catalytic efficiency</p> Signup and view all the answers

    Which statement accurately describes the binding characteristics of uncompetitive inhibitors?

    <p>They bind to the enzyme regardless of substrate presence</p> Signup and view all the answers

    How does a noncompetitive inhibitor alter the Lineweaver-Burk plot?

    <p>It results in a shift of the y-intercept</p> Signup and view all the answers

    What happens to the enzyme's Vmax when affected by an uncompetitive inhibitor?

    <p>Vmax is decreased</p> Signup and view all the answers

    Study Notes

    Enzymes

    • Enzymes are biological catalysts that speed up the rate of thermodynamically favorable biological reactions.
    • They accelerate reactions without altering the reaction equilibrium, being consumed in the overall reaction, and are required in small quantities.
    • Enzymes are highly specific for their substrate, possessing active sites.

    Enzyme Structure

    • Enzymes are mostly three-dimensional globular proteins with tertiary and quaternary structure.
    • Some RNA species enzymes are called Ribozymes.

    Active Site

    • The active site is a specialized region where a substrate can fit precisely, facilitating chemical reactions.
    • The amino acids R-groups (side chains) in the active site contribute to the specific chemical environment that favors the reaction.

    Substrate

    • The substrate is the molecule that an enzyme reacts with and binds to the active site.
    • Enzymes are specific to their substrates, determined by the active site.

    Apoenzyme, Coenzyme, Holoenzyme

    • Apoenzyme is the protein part of a conjugated enzyme.
    • Coenzyme (Cofactor) is the non-protein part of a conjugated enzyme.
    • Holoenzyme is the biochemically active conjugated enzyme, consisting of both the protein and non-protein parts.

    Enzyme Nomenclature

    • Enzymes are named according to the type of reaction they catalyze and/or their substrate.
    • The suffix "ase" is often used for enzymes, with a prefix denoting the type of reaction the enzyme catalyzes (e.g., oxidase, hydrolase).

    Major Classes of Enzymes

    • Oxidoreductases: Catalyze oxidation/reduction reactions, acting on chemical groupings to add or remove hydrogen atoms. Examples: oxidase, reductase, dehydrogenase.
    • Transferases: Transfer functional groups (e.g., methyl or phosphate) between donor and acceptor molecules. Examples: transaminases, kinases.
    • Hydrolases: Catalyze the hydrolysis of various bonds, adding water across a bond. Examples: lipase, proteases, nucleases, carbohydrases, phosphatases.
    • Lyases: Cleave various bonds by means other than hydrolysis and oxidation, adding or removing water, ammonia, or carbon dioxide across double bonds. Examples: dehydratases, decarboxylases, deaminases, hydratase.
    • Isomerases: Catalyze isomerization changes within a single molecule. Examples: mutase reactions, racemases.
    • Ligases: Join two molecules with covalent bonds, catalyzing reactions where two chemical groups are joined (or ligated) using energy from ATP. Examples: synthetases, carboxylases.

    Factors Affecting Enzyme Activity

    • Temperature: Increased temperature generally increases enzyme kinetics due to more collisions and increased reaction rate.
    • pH: Most enzymes are active over a narrow pH range, with optimal activity at a specific pH (pHOPT). Changes in pH can lead to denaturation and loss of function.
    • Substrate Concentration: Increased substrate concentration increases reaction rate until a saturation point is reached where the reaction rate remains constant despite further substrate increase.
    • Enzyme Concentration: Increased enzyme concentration increases reaction rate, with a greater enzyme concentration resulting in a higher reaction rate.

    Enzyme Inhibition

    • Inhibition: A substance that slows down or stops the normal catalytic function of an enzyme.
    • Types of Inhibition:
      • Reversible Competitive Inhibition: Inhibitor binds reversibly to the active site, competing with the substrate. Increasing substrate concentration can overcome inhibition.
      • Reversible Non-competitive Inhibition: Inhibitor binds to a site other than the active site, changing the enzyme's conformation and reducing its activity. Increased substrate concentration cannot overcome inhibition.
      • Irreversible Inhibition: Inhibitor binds irreversibly to the enzyme, permanently inactivating it.

    Medical Applications of Enzymes

    • Lactate dehydrogenase (LDH): Increased levels in the blood indicate myocardial infarction (heart attack).
    • Tissue plasminogen activator (TPA): Activates plasminogen, which dissolves blood clots. Used in the treatment of MI.

    Enzymes as Therapeutic Agents (Drugs)

    • Streptokinase: Clot lysis in myocardial infarction, trauma, and bleeding.
    • Asparaginase: Acute lymphocytic leukemia.
    • Adenosine deaminase: Severe combined immunodeficiency syndrome (SCID).

    Enzymes as Drug Targets

    • Dihydrofolate reductase: Antifolates such as methotrexate (cancer) and pyrimethamine (protozoa, malaria).
    • Xanthine oxidase: Allopurinol (hyperuricemia, gout).
    • Thymidylate synthase: 5-Fluorouracil & 5-fluorodeoxyuridine (cancer).
    • Glycopeptide transpeptidase: Antibiotics, penicillin.
    • HIV-Reverse transcriptase: 3′-azido-2′,3′-dideoxythymidine (AZT).
    • HIV & SARS proteases: Ritonavir, saquinavir (clinical trial phase).

    Michaelis-Menten Equation

    • Describes the relationship between the rate of an enzyme-catalyzed reaction and the substrate concentration.

    Km and Vmax Values

    • Km: A measure of an enzyme's affinity for its substrate. Lower Km indicates a higher affinity, and higher Km indicates a lower affinity.
    • Vmax: The maximum rate of an enzyme-catalyzed reaction. It is determined by the enzyme's turnover number (substrate molecules converted to product per unit time).

    Lineweaver-Burke Plot for Competitive Inhibition

    • Competitive inhibitors do not change the Vmax of enzyme reactions.
    • They increase the apparent Km value because they bind reversibly to the active site.
    • Increasing substrate concentration can overcome their inhibition.
    • Unchanged Vmax and increased Km reflect the effects of competitive inhibition.

    What are Enzymes?

    • Enzymes are biocatalysts that accelerate the rate of thermodynamically favorable biological reactions.
    • Their catalytic power can be thousands to millions of times faster than non-catalyzed reactions.

    Importance of Enzymes

    • Enzymes are essential for virtually all biological processes.
    • They act as catalysts, speeding up reactions without being consumed in the process.

    Activation Energy

    • It's the minimum amount of energy required for a reaction to occur.
    • Enzymes lower activation energy, making reactions proceed faster.

    Properties of Enzymes

    • Most enzymes are three-dimensional globular proteins.
    • Some special RNA species act as enzymes and are called Ribozymes.

    General Properties of Enzymes

    • Enzymes accelerate reactions but don't alter the reaction equilibrium.
    • They are not consumed during reactions.
    • They are required in small quantities.
    • Enzymes exhibit high catalytic power.
    • They show specificity for their substrates.
    • Enzymes possess active sites.

    Active Site

    • It's a specialized region on an enzyme where the substrate binds.
    • Provides optimal conditions for substrate conversion.

    Substrate

    • The molecule that an enzyme reacts with.
    • Binds to the active site of an enzyme.
    • Enzymes are specific to their substrates.

    Enzyme Structure

    • Enzymes can be simple proteins or conjugated proteins.
    • Conjugated enzymes consist of an apoenzyme (protein part) and a coenzyme (non-protein part).

    Enzyme Nomenclature

    • Enzymes are named according to the type of reaction they catalyze or their substrate.
    • Many digestive enzymes have the suffix "-in" (e.g., pepsin, trypsin).
    • Most other enzymes have the suffix "-ase" (e.g., lactase, amylase, lipase).

    Six Major Classes of Enzymes

    • Oxidoreductases: Catalyze oxidation-reduction reactions.
    • Transferases: Transfer functional groups between molecules.
    • Hydrolases: Catalyze the hydrolysis of various bonds.
    • Lyases: Cleave bonds by means other than hydrolysis and oxidation.
    • Isomerases: Catalyze isomerization within a single molecule.
    • Ligases: Join two molecules with covalent bonds.

    Enzyme-Substrate Complex

    • When a substrate binds to an enzyme's active site, a temporary Enzyme-Substrate Complex forms.
    • This complex facilitates the chemical reaction.

    Lock & Key Model

    • Proposes that the active site of an enzyme has a rigid shape complementary to the substrate.
    • Similar to a key fitting into a lock.

    Induced Fit Model

    • Recognizes that enzymes are flexible and can change shape upon substrate binding.
    • The active site adjusts its shape to accommodate the substrate.

    Specificity of Enzymes

    • Enzymes display various levels of specificity for their substrates:
    • Absolute Specificity: Enzyme acts on only one specific substrate.
    • Group Specificity: Enzyme acts on similar substrates with a specific functional group.
    • Linkage Specificity: Enzyme acts on a specific type of chemical bond, regardless of the rest of the molecule.
    • Stereochemical Specificity: Enzyme distinguishes between stereoisomers (e.g. L-amino acids vs. D-amino acids).

    Factors Affecting Enzymes

    • Temperature: Enzyme activity generally increases with temperature until an optimal point is reached. Beyond that, heat denatures the enzyme and reduces activity.
    • pH: Each enzyme has an optimal pH range. Small changes in pH can lead to denaturation and loss of activity.
    • Substrate Concentration: Enzyme activity increases with substrate concentration until saturation is reached. At saturation, further increases in substrate concentration have no effect.
    • Enzyme Concentration: As enzyme concentration increases, so does the reaction rate.

    Michaelis-Menten Equation

    • Describes the relationship between reaction rate and substrate concentration.
    • Explains how reaction rate increases initially but levels off due to enzyme saturation.

    Km and Vmax Values

    • Km: A measure of an enzyme's affinity for its substrate. Lower Km indicates higher affinity.
    • Vmax: The maximum rate of an enzyme-catalyzed reaction. It's determined by the enzyme's turnover number.

    Enzyme Inhibition

    • A substance that slows down or stops the normal catalytic function of an enzyme by binding to the enzyme.
    • Competitive Inhibition: Inhibitor binds to the active site, competing with the substrate. Can be overcome by increasing substrate concentration.
    • Noncompetitive Inhibition: Inhibitor binds to a site other than the active site, changing the enzyme's conformation and reducing its activity. Not affected by increasing substrate concentration.
    • Uncompetitive Inhibition: Inhibitor binds only to the enzyme-substrate complex. Decreases both Vmax and Km.

    Lineweaver-Burke Plot

    • Used to graphically represent enzyme kinetics and analyze different types of inhibition.
    • X-axis: 1/[S] (reciprocal of substrate concentration)
    • Y-axis: 1/V (reciprocal of reaction rate)

    Allosteric Site

    • It's a regulatory site on an enzyme, distinct from the active site, where effector molecules can bind.
    • Positive Allosteric Regulation: Binding of the effector increases enzyme activity.
    • Negative Allosteric Regulation: Binding of the effector decreases enzyme activity.

    Enzyme Definition and Nomenclature

    • Enzymes are biological catalysts that speed up chemical reactions without being consumed in the process.
    • Enzymes are named based on the type of reaction they catalyze and/or their substrate.
    • Most enzymes end in "-ase" (e.g., lactase, amylase, lipase).
    • Some digestive enzymes end in "-in" (e.g., pepsin, trypsin, chymotrypsin).
    • Prefixes denote the type of reaction the enzyme catalyzes (e.g., oxidase for redox reactions, hydrolase for hydrolysis).

    6 Major Classes of Enzymes

    • Oxidoreductases: Catalyze oxidation-reduction reactions (e.g., oxidase, reductase, dehydrogenase).
    • Transferases: Transfer functional groups between molecules (e.g., transaminases, kinases).
    • Hydrolases: Catalyze hydrolysis reactions by adding water across a bond (e.g., lipase, protease, nuclease, carbohydrases, phosphatases).
    • Lyases: Cleave bonds using mechanisms other than hydrolysis or oxidation (e.g., dehydratases, decarboxylases, deaminases, hydratase).
    • Isomerases: Catalyze isomerization changes within a single molecule (e.g., mutases, racemases, isomerases).
    • Ligases: Join two molecules with covalent bonds using ATP energy (e.g., synthetases, carboxylases).

    Enzyme-Substrate Complex

    • When a substrate binds to an enzyme's active site, an enzyme-substrate complex is formed.
    • This complex allows the substrate to undergo its chemical reaction much faster.

    Lock and Key Model of Enzyme Action

    • The active site has a rigid shape, like a lock, and the substrate fits into it like a key.
    • The substrate binds to the active site, undergoes its reaction, and then the products are released.

    Induced Fit Model of Enzyme Action

    • Enzymes are flexible and constantly change their shape.
    • The shape of the active site adapts to accommodate the substrate upon binding.

    Specificity of Enzymes

    • Absolute specificity: The enzyme catalyzes a particular reaction for only one substrate (e.g., catalase for hydrogen peroxide, urease for urea).
    • Group specificity: The enzyme acts only on similar substrates with a specific functional group (e.g., carboxypeptidase on amino acids, hexokinase on hexoses).
    • Linkage specificity: The enzyme acts on a particular type of chemical bond, regardless of the rest of the molecular structure (e.g., phosphatases on phosphate-ester bonds, chymotrypsin on peptide bonds).
    • Stereochemical specificity: The enzyme can distinguish between stereoisomers (e.g., L-amino-acid oxidase catalyzes reactions of L-amino acids, not D-amino acids).

    Factors Affecting Enzymes

    • Temperature: Increased temperature generally increases enzyme activity until an optimal temperature is reached, after which activity decreases due to denaturation.
    • pH: Most enzymes have an optimal pH range, outside of which their activity decreases due to changes in protein structure.
    • Substrate concentration: Increased substrate concentration increases reaction rate until the active sites are saturated, after which the rate plateaus.
    • Enzyme concentration: Increased enzyme concentration increases reaction rate.

    Michaelis-Menten Equation

    • Describes the relationship between substrate concentration and reaction rate.

    Km and Vmax Values

    • Km: A measure of an enzyme's affinity for its substrate. Lower Km indicates higher affinity.
    • Vmax: The maximum rate of an enzyme-catalyzed reaction, determined by the enzyme's turnover number.

    Enzyme Inhibition

    • Competitive Inhibition: A reversible inhibitor that binds to the active site, competing with the substrate. Can be overcome by increasing substrate concentration.
    • Noncompetitive Inhibition: A reversible inhibitor that binds to a site other than the active site, reducing the enzyme's efficiency. Cannot be overcome by increasing substrate concentration.
    • Uncompetitive Inhibition: A reversible inhibitor that binds to the enzyme-substrate complex, decreasing both Vmax and Km.

    Allosteric Site

    • A regulatory site on an enzyme that binds effectors, which can either activate or inhibit enzyme activity.
    • Positive Allosteric Regulation: The effector increases the enzyme's affinity for the substrate.
    • Negative Allosteric Regulation: The effector decreases the enzyme's affinity for the substrate.

    Drugs Inhibiting Enzyme Activity

    • ACE Inhibitors: Inhibit angiotensin-converting enzyme, lowering blood pressure.
    • Penicillin: Inhibits transpeptidase, weakening bacterial cell walls and killing bacteria.

    Medical Uses Of Enzymes

    • Lactate Dehydrogenase (LDH): Increased levels in blood can indicate myocardial infarction (heart attack).
    • Tissue Plasminogen Activator (TPA): Activates plasminogen, dissolving blood clots and used to treat MI.

    Therapeutic Uses of Enzymes

    • Streptokinase: Used to break down blood clots in cases of myocardial infarction, trauma, or bleeding.
    • Asparaginase: Used as an anti-cancer agent, particularly for acute lymphocytic leukemia.
    • Adenosine Deaminase: Used to treat severe combined immunodeficiency syndrome (SCID).

    Enzymes as Drug Targets

    • Dihydrofolate Reductase: Targeted by antifolate drugs like methotrexate (cancer) and pyrimethamine (malaria).
    • Xanthine Oxidase: Targeted by allopurinol for hyperuricemia and gout.
    • Thymidylate Synthase: Targeted by anticancer drugs 5-fluorouracil and 5-fluorodeoxyuridine.
    • Glycopeptide Transpeptidase: Targeted by antibiotics like penicillin.
    • HIV-Reverse Transcriptase: Targeted by antiretroviral drugs like AZT.
    • HIV and SARS Proteases: Targeted by antiviral drugs like ritonavir and saquinavir.

    What are Enzymes?

    • Enzymes are biocatalysts
    • Enzymes increase the rate of biological, thermodynamically favorable reactions by thousands or millions of times

    Importance of Enzymes

    • No biological reactions work without enzymes

    Activation Energy

    • The minimum amount of energy required for a reaction to start

    Properties of Enzymes

    • Most enzymes are three-dimensional globular proteins
    • Some enzymes are special RNA species called ribozymes

    General Properties of Enzymes

    • Enzymes speed up reactions without altering the equilibrium
    • Enzymes are not used up in the reaction
    • Small quantities of enzymes are required
    • Enzymes have significant power for catalysis
    • Enzymes are highly specific to their substrates
    • Enzymes contain active sites

    Active Site

    • The active site of an enzyme is a specialized region where a substrate binds precisely
    • This microenvironment facilitates and accelerates chemical reactions by providing optimal conditions for substrate conversion
    • Active sites are made of amino acids' R-groups (side chains)

    Substrate

    • The substrate is the molecule that an enzyme reacts with
    • The substrate binds to the active site of the enzyme and is the substance that is changed during a reaction
    • Enzymes are specific to their substrates and the specificity is determined by the active site

    Enzyme Structure

    • Enzymes can have different levels of structure: primary, secondary, tertiary, and quaternary

    Enzyme Definition

    • Apoenzyme: The protein portion of a conjugated enzyme
    • Coenzyme (Cofactor): The non-protein portion of a conjugated enzyme
    • Holoenzyme: The biochemically active conjugated enzyme (includes both the protein and non-protein parts)

    Enzyme Nomenclature

    • Enzymes are named based on the reaction they catalyze or their substrate
    • Many digestive enzymes have the suffix "-in" - ex. pepsin, trypsin, chymotrypsin
    • Most other enzyme names end with "-ase" -- ex. lactase, amylase, lipase, protease
    • The prefix of an enzyme name refers to the type of reaction:
      • Oxidase: redox reaction
      • Hydrolase: addition of water to break a component into two parts

    6 Major Classes of Enzymes

    • EC 1. Oxidoreductases
      • Catalyze oxidation/reduction
        • Oxidase: oxidation of substrate
        • Reductase: reduction of substrate
        • Dehydrogenase: introduction of a double bond by removing two hydrogen atoms
    • EC 2. Transferases
      • Transfer functional groups (e.g. methyl or phosphate) between molecules
        • Transaminases: transfer of an amino group
        • Kinases: transfer of a phosphate group
    • EC 3. Hydrolases
      • Catalyze the hydrolysis of various bonds by adding water across a bond
        • Lipase: hydrolysis of ester linkages in lipids
        • Proteases: hydrolysis of amide linkages in proteins
        • Nucleases: hydrolysis of sugar phosphate ester bonds in nucleic acids
        • Carbohydrases: hydrolysis of glycosidic bonds in carbohydrates
        • Phosphatases: hydrolysis of phosphate-ester bonds
    • EC 4. Lyases
      • Cleave various bonds by means other than hydrolysis or oxidation
      • Add water, ammonia, or carbon dioxide across double bonds or remove these elements to produce double bonds
        • Dehydratases: removal of H2O from substrate
        • Decarboxylases: removal of CO2 from substrate
        • Deaminases: removal of NH3 from substrate
        • Hydratase: addition of H2O to a substrate
    • EC 5. Isomerases
      • Catalyze isomerization changes within a single molecule
        • Mutase reactions: shift chemical groups
        • Racemases: convert D to L isomers or vice versa
    • EC 6. Ligases
      • Catalyze the joining of two molecules, often coupled with the hydrolysis of ATP

    Michaelis-Menten Equation

    • Describes the relationship between the rate of an enzyme-catalyzed reaction and substrate concentration

    Km and Vmax Values

    • Km is a measure of an enzyme's affinity for its substrate:
      • A lower Km indicates higher affinity
      • A higher Km indicates lower affinity
    • Vmax is the maximum rate of an enzyme reaction:
      • It is determined by the enzyme's turnover number (substrate molecules converted per unit time)

    Enzyme Inhibition

    • A substance that slows down or stops the normal catalytic function of an enzyme by binding to it
    • Three types of inhibition:
      • Reversible competitive inhibition
      • Reversible noncompetitive inhibition
      • Irreversible inhibition

    Competitive Inhibition

    • The inhibitor binds reversibly to the active site of the enzyme
    • Increasing substrate concentration can overcome this inhibition
    • Unchanged Vmax but increased Km reflects the effects of competitive inhibition

    Noncompetitive Inhibition

    • The inhibitor binds to a site other than the active site
    • The inhibitor reduces the concentration of the enzyme-substrate (ES) complex
    • Vmax decreases, but Km remains unchanged

    Uncompetitive Inhibition

    • The inhibitor binds to the enzyme-substrate complex
    • Decreases both Vmax and Km
    • Cannot be reversed by increasing substrate concentration

    Allosteric Site

    • The regulatory site of an enzyme that binds to effector or non-substrate molecules
    • Allosteric sites can activate or inhibit enzyme activity

    Types of Allosteric Regulation

    • Positive Allosteric Regulation: Binding of the effector increases enzyme activity by increasing its affinity to the substrate
    • Negative Allosteric Regulation: Binding of the effector decreases enzyme activity by decreasing the affinity for the substrate

    Drugs Inhibiting Enzyme Activity

    • ACE Inhibitors: inhibit angiotensin-converting enzyme, lowers blood pressure
    • Penicillins: β-lactam antibiotics that inhibit transpeptidase
      • Transpeptidase strengthens the cell wall of bacteria
      • Penicillin weakens the cell wall, causing the bacteria to die

    Medical Uses of Enzymes

    • Lactate dehydrogenase (LDH): Increased levels in the blood indicate myocardial infarction (heart attack)
    • Tissue plasminogen activator (TPA): Activates plasminogen, which dissolves blood clots. Used in MI treatment.

    Enzymes as Therapeutic Agents (Drugs)

    • Streptokinase: Clot lysis, in myocardial infarction, trauma, or bleeding
    • Asparaginase: Acute lymphocytic leukemia
    • Adenosine Deaminase: Severe combined immunodeficiency syndrome (SCID)

    Enzymes as Drug Targets

    • Dihydrofolate reductase: Antifolates like methotrexate (cancer) and pyrimethamine (protozoa & malaria)
    • Xanthine oxidase: Allopurinol for hyperuricemia and gout
    • Thymidylate synthase: 5-Fluorouracil and 5-fluorodeoxyuridine (cancer)
    • Glycopeptide transpeptidase: Antibiotics, penicillin
    • HIV-Reverse transcriptase: 3’-azido-2’,3’-dideoxythymidine (AZT)
    • HIV & SARS proteases: Ritonavir and saquinavir (clinical trials)

    Enzymes

    • Enzymes are biocatalysts that increase the rate of thermodynamically favorable biological reactions.
    • They can accelerate reactions by several thousand to million folds.
    • Enzymes are essential for life and are involved in virtually every biological process.

    Importance of Enzymes

    • Enzymes are biological catalysts, meaning they speed up reactions without being consumed in the process.
    • They are crucial for vital processes like metabolism, digestion, and DNA replication.

    Activation Energy

    • Activation energy is the minimum energy required for a reaction to occur.
    • Enzymes lower the activation energy, making reactions happen faster.

    Properties of Enzymes

    • Most enzymes are globular proteins with tertiary and quaternary structures.
    • Some special RNA molecules called ribozymes also have enzymatic activity.

    General Properties of Enzymes

    • Enzymes accelerate reactions but do not alter the equilibrium of the reaction.
    • They are not consumed during the reaction.
    • They are required in small quantities.
    • Enzymes have high catalytic power, meaning they can accelerate reactions significantly.
    • Enzymes are highly specific for their substrates.
    • Enzymes have active sites.

    Active Site

    • The active site is a specific region on an enzyme where the substrate binds.
    • The active site provides an optimal environment for the substrate to be converted into a product.

    Substrate

    • The substrate is the molecule that an enzyme reacts with.
    • It binds to the active site of the enzyme.
    • The specificity of an enzyme is determined by the active site, which fits only specific substrates.

    Apoenzyme, Coenzyme, Holoenzyme

    • An apoenzyme is the protein part of a conjugated enzyme.
    • A coenzyme is the non-protein part of a conjugated enzyme.
    • A holoenzyme is the biochemically active conjugated enzyme formed by the combination of an apoenzyme and a coenzyme.

    Enzyme-Substrate Complex

    • When a substrate binds to the active site of an enzyme, an enzyme-substrate complex is formed temporarily.
    • This complex allows the substrate to undergo its chemical reaction much faster.

    Lock and Key Model of Enzyme Action

    • The active site has a rigid shape (the lock), and the substrate (the key) must fit exactly into it.
    • This model explains the specificity of enzymes.

    Induced Fit Model of Enzyme Action

    • Many enzymes are flexible and change shape constantly.
    • The shape of the active site changes to accommodate the substrate, fitting it like a hand in a glove.

    Specificity of Enzymes

    • Enzymes can be categorized based on their specificity:
      • Absolute Specificity: An enzyme catalyzes a particular reaction for only one substrate.
      • Group Specificity: An enzyme acts only on similar substrates that have a specific functional group.
      • Linkage Specificity: An enzyme acts on a particular type of chemical bond, regardless of the rest of the molecular structure.
      • Stereochemical Specificity: An enzyme can distinguish between stereoisomers.

    Factors Affecting Enzymes

    • Various factors can affect the activity of an enzyme:

      • Temperature: Increasing temperature increases the rate of an enzyme-catalyzed reaction until a certain point, after which the enzyme denatures and loses activity.
      • pH: Each enzyme has an optimal pH range for activity.
      • Substrate Concentration: Increasing substrate concentration increases the reaction rate until the enzyme becomes saturated.
      • Enzyme Concentration: Increasing enzyme concentration increases the reaction rate.

    Michaelis-Menten Equation

    • The Michaelis-Menten equation describes the relationship between the rate of an enzyme-catalyzed reaction and the substrate concentration.

    Km and Vmax Values

    • Km: The Michaelis constant, which is a measure of an enzyme's affinity for its substrate. A lower Km indicates a higher affinity, while a higher Km indicates a lower affinity.
    • Vmax: The maximum rate of an enzyme-catalyzed reaction. It is determined by the enzyme's turnover number (the number of substrate molecules converted to product per unit time).

    Enzyme Inhibition

    • A substance that slows down or stops the normal catalytic function of an enzyme by binding to the enzyme. Types of inhibition:

      • Reversible Competitive Inhibition: The inhibitor competes with the substrate for the active site.
      • Reversible Non-competitive Inhibition: The inhibitor binds to a site on the enzyme other than the active site, altering the enzyme's shape and reducing its activity.
      • Irreversible Inhibition: The inhibitor binds permanently to the enzyme, causing permanent inactivation.

    Allosteric Site

    • The allosteric site is a regulatory site on an enzyme where effectors bind to either activate or inhibit the enzyme's activity.

    Types of Allosteric Regulation

    • Positive Allosteric Regulation: Binding of the effector increases the enzyme's affinity for the substrate, leading to an increase in enzyme activity.
    • Negative Allosteric Regulation: Binding of the effector decreases the enzyme's affinity for the substrate, leading to a decrease in enzyme activity.

    Drugs Inhibiting Enzyme Activity

    • Many drugs work by inhibiting specific enzymes to treat various diseases:

      • ACE Inhibitors: Inhibit Angiotensin-Converting Enzyme (ACE) to lower blood pressure.
      • Penicillin: Inhibits transpeptidase, an enzyme that strengthens bacterial cell walls, leading to bacterial death.

    Medical Uses of Enzymes

    • Enzymes play important roles in diagnosis and treatment of various diseases:
      • Lactate Dehydrogenase (LDH): Increased levels in blood indicate myocardial infarction (heart attack).
      • Tissue Plasminogen Activator (TPA): Activates plasminogen, an enzyme that dissolves blood clots, used in the treatment of myocardial infarction (heart attack).

    Enzymes as Therapeutic Agents

    • Some enzymes can be used as therapeutic agents (drugs) to treat various medical conditions:

      • Streptokinase: Used for clot lysis in myocardial infarction, trauma, and bleedings.
      • Asparaginase: Used for acute lymphocytic leukemia.
      • Adenosine Deaminase: Used for treatment of Severe Combined Immuno-deficiency Syndrome (SCID).

    Enzymes as Drug Targets

    • Many enzymes are targeted by drugs to treat various diseases:

      • Dihydrofolate Reductase: Targeted by antifolates like methotrexate (cancer) and pyrimethamine (protozoa, malaria).
      • Xanthine Oxidase: Targeted by allopurinol for hyperuricemia and gout.
      • Thymidylate Synthase: Targeted by 5-fluorouracil and 5-fluorodeoxyuridine for cancer treatment.
      • Glycopeptide Transpeptidase: Targeted by antibiotics like penicillin.
      • HIV-Reverse Transcriptase: Targeted by 3'-azido-2',3'-dideoxythymidine (AZT).
      • HIV & SARS Proteases: Targeted by ritonavir and saquinavir (clinical trial phase).

    Enzymes: Biocatalysts

    • Enzymes are biological catalysts that accelerate the rate of thermodynamically favorable reactions by several thousand to million folds.
    • Enzymes are essential for all biological processes.
    • Catalysts are chemical substances that speed up reactions but are not used up in the process.
    • The activation energy of a reaction is the required input of energy to make a reaction start.

    Enzyme Characteristics

    • Most enzymes are globular proteins with tertiary and quaternary structures.
    • Some enzymes are RNA molecules known as ribozymes.
    • Enzymes accelerate reactions without altering the equilibrium.
    • They are not consumed in the reaction and are required in small quantities.
    • Enzymes exhibit high specificity for their substrates.
    • Enzymes possess active sites, specialized regions where substrates bind precisely.
    • The active site facilitates and accelerates chemical reactions by providing optimal conditions for substrate conversion.

    Enzyme Nomenclature

    • Enzymes are named according to the type of reaction they catalyze and/or their substrate.
    • The suffix "ase" is commonly used for enzyme names, with a prefix indicating the type of reaction catalyzed (e.g., oxidase, hydrolase).

    Enzyme Classification

    • Enzymes are categorized into six major classes based on their catalytic activity:

      Oxidoreductases

      • Catalyze oxidation-reduction reactions
      • Act on various chemical groupings to add or remove hydrogen atoms.
      • Examples: oxidases, reductases, dehydrogenases.

      Transferases

      • Catalyze the transfer of functional groups between donor and acceptor molecules.
      • Examples: transaminases, kinases.

      Hydrolases

      • Catalyze the hydrolysis of various bonds by adding water across the bond.
      • Degrade complex molecules into simpler units.
      • Examples: lipases, proteases, nucleases, carbohydrases, phosphatases.

      Lyases

      • Catalyze the cleavage of various bonds by means other than hydrolysis and oxidation.
      • Can add elements like water, ammonia, or carbon dioxide across double bonds or remove them to produce double bonds.
      • Examples: dehydratases, decarboxylases, deaminases, hydratases.

      Isomerases

      • Catalyze isomerization changes within a single molecule.
      • Rearrange atoms within a molecule without changing the overall composition.
      • Examples: mutases.

      Ligases

      • Join two molecules together, often with the help of ATP.
      • Form new bonds between molecules.
      • Examples: synthetases.

    Enzyme Activity

    • The Michaelis-Menten equation describes the relationship between the rate of an enzyme-catalyzed reaction and the substrate concentration.

    Enzyme Kinetics

    • Km: A measure of an enzyme's affinity for its substrate.
      • Lower Km indicates a higher affinity.
      • Higher Km indicates a lower affinity.
    • Vmax: The maximum rate of an enzyme-catalyzed reaction.
      • Determined by the enzyme's turnover number (the number of substrate molecules converted to product per unit time).

    Enzyme Inhibition

    • Inhibition: A substance that slows down or stops the normal catalytic function of an enzyme by binding to the enzyme.
    • Reversible Inhibition: The inhibitor binds reversibly to the enzyme and can be overcome by increasing substrate concentration.
      • Competitive Inhibition: The inhibitor binds to the active site of the enzyme, competing with the substrate for binding.
      • Noncompetitive Inhibition: The inhibitor binds to a site other than the active site, altering both the enzyme's affinity for the substrate and its ability to catalyze the reaction.
    • Uncompetitive Inhibition: The inhibitor binds only to the enzyme-substrate complex, decreasing both Vmax and Km.
    • Irreversible Inhibition: The inhibitor binds permanently to the enzyme, inactivating it.

    Allosteric Control

    • Allosteric Site: A regulatory site on an enzyme that binds to effector molecules.
      • Positive Allosteric Regulation: The effector increases the enzyme's affinity for the substrate, leading to an increase in enzyme activity.
      • Negative Allosteric Regulation: The effector decreases the enzyme's affinity for the substrate, leading to a decrease in enzyme activity.

    Medical Uses of Enzymes

    • Therapeutic Agents: Enzymes can be used as drugs for various diseases.
    • Diagnostic Markers: Enzyme levels in blood can be used to diagnose certain conditions.
    • Drug Targets: Enzymes are often targets for drugs designed to treat diseases.

    Examples of Enzyme Inhibition by Drugs

    • ACE Inhibitors: Inhibit the angiotensin-converting enzyme (ACE), lowering blood pressure.
    • Penicillin: Inhibits transpeptidase, an enzyme that strengthens bacterial cell walls, leading to weakened cell walls and bacterial death.

    Examples of Enzyme Use in Medicine

    • Lactate Dehydrogenase (LDH): High levels in blood indicate myocardial infarction (heart attack).
    • Tissue Plasminogen Activator (TPA): Dissolves blood clots by activating plasminogen. Used in the treatment of MI.

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    Week 9- Enzymes PDF

    Description

    Explore the fascinating world of enzymes in this quiz, covering their role as biological catalysts and their unique structures. Test your knowledge on enzyme specificity, active sites, and the differences between apoenzymes and coenzymes. Perfect for students studying biochemistry or related fields.

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