Textbook Question
Answer questions (a)–(e) concerning the following reaction:
c. What is the substrate for the reaction as written?
Ch.19 Enzymes and Vitamins
McMurry8th EditionFundamentals of GOBISBN: 9780134015187
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Table of contents
- Ch.1 Matter and Measurements27
- Ch.2 Atoms and the Periodic Table20
- Ch.3 Ionic Compounds8
- Ch.4 Molecular Compounds23
- Ch.5 Classification & Balancing of Chemical Reactions12
- Ch.6 Chemical Reactions: Mole and Mass Relationships28
- Ch.7 Chemical Reactions: Energy, Rate and Equilibrium64
- Ch.8 Gases, Liquids and Solids24
- Ch.9 Solutions52
- Ch.10 Acids and Bases25
- Ch.11 Nuclear Chemistry22
- Ch.12 Introduction to Organic Chemistry: Alkanes57
- Ch.13 Alkenes, Alkynes, and Aromatic Compounds47
- Ch.14 Some Compounds with Oxygen, Sulfur, or a Halogen50
- Ch.15 Aldehydes and Ketones45
- Ch.16 Amines42
- Ch.17 Carboxylic Acids and Their Derivatives57
- Ch.18 Amino Acids and Proteins82
- Ch.19 Enzymes and Vitamins63
- Ch.20 Carbohydrates44
- Ch.21 The Generation of Biochemical Energy65
- Ch.22 Carbohydrate Metabolism45
- Ch.23 Lipids42
- Ch.24 Lipid Metabolism33
- Ch.25 Protein and Amino Acid Metabolism24
- Ch.26 Nucleic Acids and Protein Synthesis45
Chapter 19, Problem 28b
Explain how the following changes affect the rate of an enzyme-catalyzed reaction in the presence of an uncompetitive inhibitor:
(b) decreasing the inhibitor concentration at a constant substrate concentration.
Verified step by step guidance1
Understand the role of an uncompetitive inhibitor: An uncompetitive inhibitor binds only to the enzyme-substrate complex, preventing the reaction from proceeding to form the product. This type of inhibition decreases both the maximum reaction rate (Vmax) and the Michaelis constant (Km) proportionally, without changing their ratio.
Recognize the effect of inhibitor concentration: Decreasing the concentration of the uncompetitive inhibitor reduces its ability to bind to the enzyme-substrate complex. This means that more enzyme-substrate complexes are free to proceed to product formation.
Analyze the impact on Vmax: Since the uncompetitive inhibitor reduces Vmax, lowering the inhibitor concentration will allow the reaction to approach a higher Vmax, increasing the overall reaction rate.
Consider the substrate concentration: At a constant substrate concentration, the availability of enzyme-substrate complexes is fixed. Reducing the inhibitor concentration will increase the fraction of these complexes that can proceed to product formation, further increasing the reaction rate.
Summarize the overall effect: Decreasing the inhibitor concentration at a constant substrate concentration will increase the rate of the enzyme-catalyzed reaction because fewer enzyme-substrate complexes are inhibited from forming the product.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Enzyme-Catalyzed Reactions
Enzyme-catalyzed reactions are biochemical processes where enzymes accelerate the conversion of substrates into products. The rate of these reactions is influenced by factors such as substrate concentration, enzyme concentration, temperature, and pH. Understanding the basic mechanics of how enzymes function is crucial for analyzing the effects of inhibitors.
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Acid-Catalyzed Ester Hydrolysis Example 1
Uncompetitive Inhibition
Uncompetitive inhibition occurs when an inhibitor binds to the enzyme-substrate complex, preventing the complex from releasing products. This type of inhibition decreases both the maximum reaction rate (Vmax) and the apparent affinity of the enzyme for the substrate (Km). It is essential to recognize how uncompetitive inhibitors alter the kinetics of enzyme reactions to understand their impact on reaction rates.
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Inhibitor Concentration Effects
The concentration of an inhibitor can significantly influence the rate of an enzyme-catalyzed reaction. In the case of uncompetitive inhibition, decreasing the inhibitor concentration while keeping substrate levels constant can lead to an increase in the reaction rate. This is because fewer inhibitor molecules are available to bind to the enzyme-substrate complex, allowing more complexes to convert into products.
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Related Practice
Textbook Question
Answer questions (a)–(e) concerning the following reaction:
d. What is the product for the reaction as written?
Textbook Question
Explain how the following changes affect the rate of an enzyme-catalyzed reaction in the presence of an uncompetitive inhibitor:
(a) increasing the substrate concentration at a constant inhibitor concentration
Textbook Question
Explain how the following mechanisms regulate enzyme activity.
b. Genetic control
Textbook Question
What type of enzyme regulation occurs in the following situations?
a. Buildup of the product of the pathway that converts glucose to pyruvate stops at the first enzyme in the multistep process.
Textbook Question
What type of enzyme regulation occurs in the following situations?
d. Conversion of isocitrate to α-ketoglutarate is inhibited by high levels of ATP. (Hint: ATP is neither a product nor a substrate in this reaction.)