Podcast
Questions and Answers
What temperature range is considered the optimal temperature for enzyme activity?
What temperature range is considered the optimal temperature for enzyme activity?
- 25°C to 35°C
- 30°C to 40°C (correct)
- 35°C to 45°C
- 40°C to 50°C
What happens to an enzyme when it is exposed to temperatures between 40°C and 50°C?
What happens to an enzyme when it is exposed to temperatures between 40°C and 50°C?
- It becomes more active.
- It is unaffected.
- It is permanently inactivated.
- It undergoes a conformational change. (correct)
What is the effect of a 10°C increase in temperature on the activity of an enzyme, according to the Q10 concept?
What is the effect of a 10°C increase in temperature on the activity of an enzyme, according to the Q10 concept?
- The activity doubles. (correct)
- The activity decreases by half.
- The activity increases by tenfold.
- The activity remains the same.
What is the ideal storage temperature for substrates and coenzymes?
What is the ideal storage temperature for substrates and coenzymes?
Which of the following enzymes is classified as a hydrolase?
Which of the following enzymes is classified as a hydrolase?
What is the standardized system for classifying and naming enzymes?
What is the standardized system for classifying and naming enzymes?
Which of the following factors can influence the activity of an enzyme?
Which of the following factors can influence the activity of an enzyme?
Which of the following enzymes is NOT classified as an oxidoreductase?
Which of the following enzymes is NOT classified as an oxidoreductase?
What happens to the reaction rate when the enzyme concentration increases?
What happens to the reaction rate when the enzyme concentration increases?
When an inhibitor binds to the allosteric site of an enzyme, what type of inhibition is it generally considered?
When an inhibitor binds to the allosteric site of an enzyme, what type of inhibition is it generally considered?
Which of the following is NOT a characteristic of isoenzymes?
Which of the following is NOT a characteristic of isoenzymes?
What effect does a competitive inhibitor have on the Michaelis-Menten constant (Km) of an enzyme?
What effect does a competitive inhibitor have on the Michaelis-Menten constant (Km) of an enzyme?
Which one is an example of an inorganic activator that alters the spatial configuration of an enzyme?
Which one is an example of an inorganic activator that alters the spatial configuration of an enzyme?
What is the ES complex in enzyme kinetics?
What is the ES complex in enzyme kinetics?
Which of the following statements is true about enzymes?
Which of the following statements is true about enzymes?
What is the role of a coenzyme in enzyme kinetics?
What is the role of a coenzyme in enzyme kinetics?
Which of the following enzymes catalyzes the removal of a group from a substrate without hydrolysis?
Which of the following enzymes catalyzes the removal of a group from a substrate without hydrolysis?
What type of enzyme specificity does an enzyme exhibit if it combines with all substrates in a particular chemical group?
What type of enzyme specificity does an enzyme exhibit if it combines with all substrates in a particular chemical group?
Which of the following is NOT a general method used in enzyme reaction studies?
Which of the following is NOT a general method used in enzyme reaction studies?
The 'Induced Fit' theory of enzyme action states that:
The 'Induced Fit' theory of enzyme action states that:
In a zero-order enzyme reaction, the reaction rate is primarily dependent on:
In a zero-order enzyme reaction, the reaction rate is primarily dependent on:
What is the standard unit of enzyme activity known as?
What is the standard unit of enzyme activity known as?
Which of the following is NOT a factor considered when defining an activity unit for enzymes?
Which of the following is NOT a factor considered when defining an activity unit for enzymes?
Which of the following enzymes is an example of a ligase?
Which of the following enzymes is an example of a ligase?
Flashcards
Enzyme
Enzyme
A protein that hastens chemical reactions in organic matter.
Active Site
Active Site
The specific region where substrates bind on an enzyme.
Allosteric Site
Allosteric Site
A site on the enzyme that binds regulator molecules, affecting activity.
ES Complex
ES Complex
The physical binding of a substrate to the enzyme’s active site.
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Competitive Inhibitor
Competitive Inhibitor
A molecule that competes with substrate for the active site on an enzyme.
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Non-competitive Inhibitor
Non-competitive Inhibitor
A substance that binds to an allosteric site, inhibiting enzyme activity without competing.
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Coenzymes
Coenzymes
Organic compounds that assist enzymes by helping substrates to fit.
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Isoenzymes
Isoenzymes
Enzymes with different molecular structures but catalyze the same reaction.
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Temperature Effect on Enzymes
Temperature Effect on Enzymes
Higher temperature increases the activity of chemical reactions and enzymes up to a certain point, after which enzymes can denature.
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Temperature Coefficient (Q10)
Temperature Coefficient (Q10)
For every 10°C increase in temperature, enzyme activity can double.
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Optimal pH for Reactions
Optimal pH for Reactions
Physiological reactions typically occur optimally at pH levels between 7 and 8.
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Effect of Extreme pH
Effect of Extreme pH
Extreme pH levels can denature enzymes, alter ionic states, cause structural changes, and change the charge of amino acids.
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Enzyme Storage Temperature
Enzyme Storage Temperature
Low temperatures (like refrigeration) can keep enzymes reversibly inactive, while too much freezing can cause denaturation.
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Enzyme Nomenclature
Enzyme Nomenclature
Enzymes are named and classified by the Enzyme Commission based on function, substrate catalyzed, and class of reaction.
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Enzyme Classification: Oxidoreductases
Enzyme Classification: Oxidoreductases
Enzymes that catalyze the removal or addition of electrons in oxidation-reduction (redox) reactions.
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Enzyme Example: Alkaline Phosphatase (ALP)
Enzyme Example: Alkaline Phosphatase (ALP)
A specific enzyme classified as a hydrolase that catalyzes the removal of phosphate groups from various compounds.
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Lyases
Lyases
Enzymes that catalyze the removal of groups without hydrolysis.
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Isomerases
Isomerases
Enzymes that catalyze intramolecular rearrangements of substrates.
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Ligase
Ligase
Enzymes that join two substrates while breaking a pyrophosphate bond.
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Lock and Key Theory
Lock and Key Theory
Model suggesting substrate fits enzyme's active site like a key into a lock.
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Induced Fit Theory
Induced Fit Theory
Model where enzyme changes shape to accommodate the substrate upon binding.
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Absolute Specificity
Absolute Specificity
Enzymes that catalyze only one reaction with a specific substrate.
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Enzyme Kinetics
Enzyme Kinetics
Study of how enzyme reactions depend on substrate concentration and energy.
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International Unit (IU)
International Unit (IU)
Measurement indicating 1 micromole of substrate processed per minute.
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Enzymes
- Enzymes hasten chemical reactions in organic matter
- Catalyze specific chemical reactions
- Found in large quantities within cells
- Increase membrane permeability, allowing them to enter the bloodstream
- Measured by activity, not absolute value
- Appear in serum after cell injury, degradation, or storage
- Specific to a substrate, converting it to a defined product
- Used clinically as a sign of organ damage
Enzyme Components
- Active site: Water-free cavity where substrate interacts
- Allosteric site: Cavity other than the active site, binding regulator molecules
ES Complex
- Physical binding of a substrate to the enzyme's active site
Factors Affecting Enzymatic Reactions
- Enzyme Concentration: Higher concentration results in faster reaction rate within the substrate range
- Substrate Concentration: Reaction rate increases with substrate up to saturation. Further increases have no effect
- Cofactors:
- Coenzymes: Organic molecules aiding substrate fit. Increased coenzymes increase reaction velocity. Examples include NAD and NADP
- Activators: Inorganic ions altering enzyme shape for proper binding. Examples include calcium, zinc, chloride, magnesium, and potassium.
- Metalloenzymes: Inorganic ions attached to the enzyme. Examples include catalase and cytochrome oxidase.
Inhibitors
- Competitive Inhibitors: Bind to the active site, competing with the substrate. Reversible if substrate surpasses inhibitor concentration
- Noncompetitive Inhibitors: Do not compete with the substrate (bind to an allosteric site), causing irreversible inhibition.
- Uncompetitive Inhibitors: Bind to the enzyme-substrate complex (ES), increasing inhibition with increased substrate
Isoenzymes
- Enzymes with identical, catalytic reactions yet varying structures and amino acid sequences
Temperature
- Optimal temperature is 25-37 degrees Celsius
- Denaturation occurs above 40 degrees Celsius
- Inactivation above 60-65 degrees Celsius
- Temperature coefficient (Q10): a 10-degree increase in temperature leads to roughly a twofold increase in enzyme activity
pH
- Physiological range is 7-8
- Extreme pH denatures enzymes and alters charge in the amino acid residues within the active site
Storage
- Low temperatures (refrigeration/freezing) result in reversible inactivity.
- Repeated freezing/thawing denatures proteins
- -20 degrees Celsius is best for long-term storage
- 2-8 degrees Celsius is suitable for substrate and coenzyme storage
- Room temperature is good for LD4 and LD5 storage
Hemolysis
- Increased enzyme concentration due to erythrocyte rupture
Lactescence/Milky Specimen
- Increased enzyme concentration
Enzyme Nomenclature
- Standardized by the Enzyme Commission (EC) using a classification system
- Classified by biochemical function, substrate catalyzed, class of reaction.
- Individual identification numbers (AMS EC 3.2.1.1)
Other factors
- Hemolysis and lactescence can cause elevated enzyme concentration
- Enzyme theory includes lock-and-key and induced-fit models
- Enzyme kinetics deals with rate of reactions and affects of factors like substrate and enzyme concentrations, temperature, etc
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Description
Explore the fascinating world of enzymes and their critical role in biological reactions. This quiz delves into enzyme components, the ES complex, and factors influencing enzymatic reactions. Enhance your understanding of how enzymes operate within living cells and their clinical significance.