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

6. Enzymes and Enzyme Kinetics

Specificity Constant

Biochemistry

6. Enzymes and Enzyme Kinetics

Specificity Constant

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Multiple Choice

Which of the following options is correct concerning the turnover number (k _cat) and the specificity constant?

k_cat reveals how well an enzyme works & its preference for S.

Specificity constant is defined as (k_cat)(K_m).

A large k_cat indicates a less efficient enzyme.

k_cat = V_max/[ES].

Specificity constant is defined as K_m / k_cat.

A small K_m indicates a more efficient enzyme.

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Verified step by step guidance

Understand the concept of turnover number (k_cat): It is defined as the number of substrate molecules converted into product by an enzyme molecule in a unit time when the enzyme is fully saturated with substrate. Mathematically, it is expressed as k_cat = V_max / [E], where V_max is the maximum rate of the reaction and [E] is the enzyme concentration.

Clarify the specificity constant: The specificity constant is a measure of how efficiently an enzyme converts a substrate into product. It is defined as k_cat / K_m, where K_m is the Michaelis constant. This ratio provides insight into both the catalytic efficiency and the enzyme's affinity for the substrate.

Evaluate the statement 'k_cat reveals how well an enzyme works & its preference for S': This is partially correct. k_cat indicates how well an enzyme works in terms of its catalytic activity, but it does not directly indicate substrate preference. Substrate preference is better assessed by the specificity constant.

Analyze the statement 'A large k_cat indicates a less efficient enzyme': This is incorrect. A large k_cat actually indicates a more efficient enzyme, as it means the enzyme can convert more substrate molecules into product per unit time when saturated.

Consider the statement 'A small K_m indicates a more efficient enzyme': This is generally true. A small K_m suggests that the enzyme has a high affinity for the substrate, meaning it can achieve half-maximal velocity at a lower substrate concentration, which is often associated with higher efficiency.