The initial velocities of two different enzyme-catalyzed reactions were measured over a series of substrate concentrations. The following results were obtained: Enyme A: KM = 1.5 mM, Vmax = 10 μµM s-1 Enyme B: KM = 5.0 mM, Vmax = 85 µM s¯1 (a) Which enzyme binds to its substrate more tightly (assume k.₁ >> k₂ in the Michaelis-Menten model)? (b) Calculate the initial velocities of each reaction when the substrate concentration is 2.5 mM. (c) Calculate the Kcat of each enzyme if the total enzyme concentration is 100 nM. (d) Which enzyme is the more efficient catalyst? Explain your answer. The enzyme carbonic anhydrase is strongly inhibited by the drug acetazolamide. A plot of the initial reaction velocity (as a percentage of Vmax) in the absence and presence of the inhibitor is shown below. What type of inhibition is taking place? Explain your reasoning. V (% of Vmax) 100 50 0.2 0.4 No inhibitor Acetazolamide [S] (MM) 0.6 0.8 1
The initial velocities of two different enzyme-catalyzed reactions were measured over a series of substrate concentrations. The following results were obtained: Enyme A: KM = 1.5 mM, Vmax = 10 μµM s-1 Enyme B: KM = 5.0 mM, Vmax = 85 µM s¯1 (a) Which enzyme binds to its substrate more tightly (assume k.₁ >> k₂ in the Michaelis-Menten model)? (b) Calculate the initial velocities of each reaction when the substrate concentration is 2.5 mM. (c) Calculate the Kcat of each enzyme if the total enzyme concentration is 100 nM. (d) Which enzyme is the more efficient catalyst? Explain your answer. The enzyme carbonic anhydrase is strongly inhibited by the drug acetazolamide. A plot of the initial reaction velocity (as a percentage of Vmax) in the absence and presence of the inhibitor is shown below. What type of inhibition is taking place? Explain your reasoning. V (% of Vmax) 100 50 0.2 0.4 No inhibitor Acetazolamide [S] (MM) 0.6 0.8 1
Biochemistry
9th Edition
ISBN:9781319114671
Author:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.
Publisher:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.
Chapter1: Biochemistry: An Evolving Science
Section: Chapter Questions
Problem 1P
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![The initial velocities of two different enzyme-catalyzed reactions were measured over a series of substrate concentrations. The
following results were obtained:
Enyme A: KM = 1.5 mM, Vmax = 10 μM s-1
Enyme B: KM = 5.0 mM, Vmax = 85 µM s-1
(a) Which enzyme binds to its substrate more tightly (assume k.1 >> k₂ in the Michaelis-Menten model)?
(b) Calculate the initial velocities of each reaction when the substrate concentration is 2.5 mM.
(c) Calculate the Kcat of each enzyme if the total enzyme concentration is 100 nM.
(d) Which enzyme is the more efficient catalyst? Explain your answer.
The enzyme carbonic anhydrase is strongly inhibited by the drug acetazolamide. A plot of the initial reaction velocity (as a percentage
of Vmax) in the absence and presence of the inhibitor is shown below. What type of inhibition is taking place? Explain your reasoning.
V (% of Vmax)
100
50
0.2
0.4
No inhibitor
Acetazolamide
[S] (MM)
0.6
0.8
1](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Ff800a840-0309-4834-92a3-4244363b7afa%2Fb5404336-3633-49f1-bb62-d142c313f368%2Fvjn6wzg_processed.jpeg&w=3840&q=75)
Transcribed Image Text:The initial velocities of two different enzyme-catalyzed reactions were measured over a series of substrate concentrations. The
following results were obtained:
Enyme A: KM = 1.5 mM, Vmax = 10 μM s-1
Enyme B: KM = 5.0 mM, Vmax = 85 µM s-1
(a) Which enzyme binds to its substrate more tightly (assume k.1 >> k₂ in the Michaelis-Menten model)?
(b) Calculate the initial velocities of each reaction when the substrate concentration is 2.5 mM.
(c) Calculate the Kcat of each enzyme if the total enzyme concentration is 100 nM.
(d) Which enzyme is the more efficient catalyst? Explain your answer.
The enzyme carbonic anhydrase is strongly inhibited by the drug acetazolamide. A plot of the initial reaction velocity (as a percentage
of Vmax) in the absence and presence of the inhibitor is shown below. What type of inhibition is taking place? Explain your reasoning.
V (% of Vmax)
100
50
0.2
0.4
No inhibitor
Acetazolamide
[S] (MM)
0.6
0.8
1
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