Table of contents

1. Introduction to Biochemistry4h 34m
2. Water3h 23m
3. Amino Acids8h 10m
4. Protein Structure10h 4m
5. Protein Techniques14h 5m
6. Enzymes and Enzyme Kinetics13h 38m
7. Enzyme Inhibition and Regulation 8h 42m
8. Protein Function 9h 41m
9. Carbohydrates7h 49m
10. Lipids5h 49m
11. Biological Membranes and Transport 6h 37m
12. Biosignaling9h 45m
Review 1: Nucleic Acids, Lipids, & Membranes2h 47m
Review 2: Biosignaling, Glycolysis, Gluconeogenesis, & PP-Pathway3h 12m
Review 3: Pyruvate & Fatty Acid Oxidation, Citric Acid Cycle, & Glycogen Metabolism2h 26m
Review 4: Amino Acid Oxidation, Oxidative Phosphorylation, & Photophosphorylation1h 48m

7. Enzyme Inhibition and Regulation

Enzyme Inhibition

Biochemistry

7. Enzyme Inhibition and Regulation

Enzyme Inhibition

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Multiple Choice

How does a noncompetitive inhibitor decrease the rate of an enzyme-catalyzed reaction?

It increases the affinity of the enzyme for its substrate, thereby decreasing the reaction rate.

It competes with the substrate for binding at the active site, increasing the apparent K_m.

It forms a covalent bond with the substrate, preventing product formation.

It binds to an allosteric site, reducing the maximum velocity (V_{max}) without affecting the Michaelis constant (K_m).

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Verified step by step guidance

Step 1: Understand the concept of enzyme inhibition. Enzyme inhibitors are molecules that reduce the activity of enzymes, and they can be classified as competitive, noncompetitive, or uncompetitive inhibitors based on their mechanism of action.

Step 2: Define noncompetitive inhibition. A noncompetitive inhibitor binds to an allosteric site on the enzyme, which is a site other than the active site. This binding changes the enzyme's conformation, reducing its ability to catalyze the reaction effectively.

Step 3: Analyze the effect of noncompetitive inhibition on enzyme kinetics. Noncompetitive inhibitors decrease the maximum velocity (V_{max}) of the reaction because they reduce the number of functional enzyme molecules available for catalysis. However, they do not affect the Michaelis constant (K_m), which represents the substrate concentration at half-maximal velocity.

Step 4: Compare noncompetitive inhibition with other types of inhibition. Unlike competitive inhibitors, which increase the apparent K_m by competing with the substrate for the active site, noncompetitive inhibitors do not interfere with substrate binding directly. Instead, they affect the enzyme's catalytic efficiency.

Step 5: Summarize the mechanism of noncompetitive inhibition. The inhibitor binds to an allosteric site, altering the enzyme's structure and reducing its catalytic activity. This results in a lower V_{max} without changing the K_m, as substrate binding is not directly impacted.