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How many (i) transition states, and (ii) intermediates are associated with this mechanism:
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Are the following statements correct descriptions of the steady state assumption used to derive the Michaelis-Menten equation?
- The concentration of enzyme in an assay is much lower than the concentration of substrate.
- The equilibrium between E, S, and ES is rapidly established.
- The concentration of the ES complex does not change during the time frame where enzyme activity is being measured.
- Product formed during the reaction does not react with E to reform ES at a significant rate
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Which of the following statements are true about the catalytic efficiency of an enzyme following the simple kinetic scheme shown here?
- a low Km and high kcat increase catalytic efficiency.
- the theoretic upper limit to catalytic efficiency is diffusion controlled.
- catalytic efficiency is a second order rate constant with a value close to k1 for a “perfect” enzyme.
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The red line on the following reaction coordinate diagram is consistent with which kinetic mechanism?
(C)
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An enzyme that follows Michaelis-Menten kinetics has a Vmax of 200.0 units and a Km of 0.100 mM. What will be the activity for this enzyme when the substrate concentration is 0.500 mM?
167 units
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Algebraically solve the Michaelis-Menten equation for [S] to answer the following question: what concentration of substrate gives an initial rate of 1500 units for an enzyme that exhibits a Vmax of 10,000 units and a Km of 0.25 mM?
0.044 mM
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Kinetic analysis of a homodimeric enzyme of 150,000 molecular weight (that is the Mr of the dimer) catalyzing conversion of substrate S to product P provides the following kinetic constants: Vmax = 1000 units when 1 mg of enzyme is assayed. Assume each subunit contains an active site; i.e. there are two active sites per dimer. Calculate the turnover number for this enzyme. In units of s-1.
1,250 s-1
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What forms of the enzyme do a competitive (C), noncompetitive (NC), and uncompetitive (UC) inhibitor bind to?
- C:E only.
- NC: E and ES.
- UC: ES only.
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Using information from the following graph of 1/v vs. 1[S] for a particular enzyme, determine the values of V max and K m
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For the kinetic scheme shown below, which rate constants are first order?
k2, k-2, k3, k-3 , k4 ,k-1
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Which statement(s) can be made with certainty about the following reaction:
the reaction is exergonic
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The following graph shows a Lineweaver-Burke ( 1/v vs. 1/[S] ) plot (indicated by an arrow) for an enzymatic reaction transforming substrate S to product P. Which line could possibly represent a competitive inhibitor?
(B)
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Which of the following strategies for rate acceleration apply to ALL enzyme-catalyzed reactions?
- binding energy
- entropy trap
- transition state stabilization
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In general, the structure of the active site of an enzyme will be most complementary to:
the structure of the transition state(s)
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