Enzyme Specificity and Catalysis
36 Questions
1 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What type of enzyme catalyzes oxidation/reduction reactions?

  • Hydrolases
  • Oxidoreductases (correct)
  • Isomerases
  • Transferases
  • What is the primary function of Trypsin?

  • To form two products from a substrate by hydrolysis (correct)
  • To isomerize a single molecule
  • To transfer a functional group from one substance to another
  • To catalyze oxidation/reduction reactions
  • What type of enzyme is Aldolase?

  • Transferase
  • Oxidoreductase
  • Lyase (correct)
  • Hydrolase
  • What is the primary function of tripeptide aminopeptidase?

    <p>To cleave amino terminal amino acid from a polypeptide</p> Signup and view all the answers

    What type of enzyme is Lactate Dehydrogenase?

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

    What type of enzyme is Alanine Amino Transferase?

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

    What is the reason why an ES complex will be in an energetic minimum?

    <p>Because the enzyme is complementary to the transition state</p> Signup and view all the answers

    What is the characteristic of enzymes that act on only a few related molecules?

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

    What determines the specificity of an enzyme?

    <p>The groove or cleft of defined shape on the enzyme</p> Signup and view all the answers

    What is the name of the classification scheme established by the I.U.B. Commission on Enzymes?

    <p>No specific name is mentioned</p> Signup and view all the answers

    What is the purpose of the 4-digit number assigned to each enzyme?

    <p>To identify the enzyme uniquely</p> Signup and view all the answers

    What is the characteristic of enzymes that act on only one substrate?

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

    What is the effect of high temperatures on the structure of enzymes?

    <p>The enzyme becomes denatured and inactive.</p> Signup and view all the answers

    What is the result of changes in ionization state of active site residues in an enzyme?

    <p>The Km of the enzyme changes.</p> Signup and view all the answers

    What is the effect of pH on enzyme-catalysed reactions?

    <p>It can affect the rate of the reaction by changing the ionization state of the substrate.</p> Signup and view all the answers

    What type of bond is formed by the action of ligases?

    <p>C-C, C-N, C-O, or C-S bonds are formed.</p> Signup and view all the answers

    What type of enzyme catalyzes isomerization reactions?

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

    What is the effect of unfolding of an enzyme on its activity?

    <p>The enzyme becomes inactivated.</p> Signup and view all the answers

    What type of enzyme catalyzes the formation of two products from a substrate by hydrolysis?

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

    Which of the following enzymes catalyzes the transfer of functional groups from one substance to another?

    <p>Alanine aminotransferase</p> Signup and view all the answers

    What type of bond is formed by Ligases during the synthesis of two molecules?

    <p>All of the above</p> Signup and view all the answers

    Which enzyme catalyzes the oxidation and reduction of lactate to form pyruvate?

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

    What type of reaction is catalyzed by Lyases?

    <p>Non-hydrolytic addition or removal of groups</p> Signup and view all the answers

    Which enzyme catalyzes the breakdown of a peptide bond?

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

    What is the energy source for the synthesis of two molecules by Ligases?

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

    What is the steady-state condition for the enzyme-substrate complex ES?

    <p>The rate of formation of ES is equal to the rate of breakdown of ES.</p> Signup and view all the answers

    Which enzyme is responsible for the transfer of an amino group from glutamate to form α-ketoglutarate?

    <p>Alanine aminotransferase</p> Signup and view all the answers

    What is the byproduct of the reaction catalyzed by Hydrolases?

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

    What is the Michaelis constant Km equal to?

    <p>(k-1 + k2) / k1</p> Signup and view all the answers

    Which enzyme is responsible for the formation of a new C-C bond?

    <p>DNA ligase</p> Signup and view all the answers

    What is the significance of Vmax in the Michaelis-Menten equation?

    <p>It is the maximal velocity of an enzyme-catalyzed reaction.</p> Signup and view all the answers

    What is the relationship between Km and [S] when V0 = 0.5Vmax?

    <p>Km = [S]</p> Signup and view all the answers

    What is the unit of V0 in the Michaelis-Menten equation?

    <p>M/min</p> Signup and view all the answers

    What is the significance of the steady-state assumption in the Michaelis-Menten equation?

    <p>It allows for the estimation of Km and Vmax.</p> Signup and view all the answers

    What is the effect of increasing the substrate concentration [S] on the initial reaction velocity V0?

    <p>V0 increases and then levels off</p> Signup and view all the answers

    What is the relationship between V0 and Vmax when [S] = Km?

    <p>V0 = 0.5Vmax</p> Signup and view all the answers

    Study Notes

    Enzyme Specificity

    • Enzymes usually catalyze only one type of reaction and act on only a few related molecules.
    • Substrate specificity is determined by the shape and charge of the active site, which allows only the correct substrate to fit.
    • Enzymes can be highly specific, acting on only one substrate or one isomer of a compound.

    Classification of Enzymes

    • Enzymes are classified into six main classes based on the type of reaction they catalyze.
    • Each class is further divided into subgroups according to their substrate or source.
    • Each enzyme is identified by a unique 4-digit number.

    Types of Enzymes

    Oxidoreductases

    • Catalyze oxidation/reduction reactions, transferring H and O atoms or electrons from one substance to another.
    • Example: Lactate Dehydrogenase.

    Transferases

    • Catalyze the transfer of functional groups from one substance to another.
    • Example: Alanine Aminotransferase.

    Hydrolases

    • Catalyze the formation of two products from a substrate by hydrolysis (splitting using water).
    • Example: Trypsin.

    Lyases

    • Catalyze non-hydrolytic addition or removal of groups from substrates, cleaving C-C, C-N, C-O, or C-S bonds.
    • Example: Aldolase.

    Isomerases

    • Catalyze isomerization changes within a single molecule.
    • Example: Phosphoglucose Isomerase (Phosphohexose Isomerase).

    Ligases

    • Join together two molecules by synthesizing new C-O, C-S, C-N, or C-C bonds with simultaneous breakdown of ATP.
    • Example: DNA Ligase.

    Properties of Enzymes

    Effects of Temperature

    • Enzyme structure is stabilized by many weak bonds, which can be easily broken by heat, leading to a disorganized or tangled structure and loss of catalytic activity.

    Effects of pH

    • Changes in pH can have direct effects on the rate of enzyme-catalyzed reactions, affecting substrate binding, active site residues, and enzyme unfolding.
    • pH changes can lead to changes in ionization states, additional acid/base catalysis, and altered substrate binding.

    Enzyme Kinetics

    • The Michaelis-Menten equation describes the kinetics of enzyme-catalyzed reactions.
    • The equation relates the initial reaction velocity (V0) to the substrate concentration ([S]), the maximal velocity (Vmax), and the Michaelis constant (Km).
    • When V0 = 0.5Vmax, the substrate concentration [S] is equal to the Michaelis constant Km.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Description

    Learn about the specificity of enzymes, how they catalyze reactions, and their complementary nature to the transition state.

    More Like This

    Enzyme Catalysis Lesson Quiz
    5 questions

    Enzyme Catalysis Lesson Quiz

    WellEstablishedRhodolite avatar
    WellEstablishedRhodolite
    Medical Biochemistry: Enzymes Chemistry
    10 questions
    Use Quizgecko on...
    Browser
    Browser