Question

Which of the following is true regarding the Michaelis-Menten graph?

• A. Km is directly proportional to substrate concentration
• B. Km is directly proportional to enzyme concentration
• C. Km is indirectly proportional to substrate concentration
• D. Km has no relation to substrate concentration

Hint:

The Michaelis constant (Km) is an intrinsic property of an enzyme and is used to measure the affinity of the enzyme for its substrate. A lower Km indicates higher affinity.

Answer 1

The Correct Option is D

Km is directly proportional to substrate concentration: This is false. Km (Michaelis constant) is a property of the enzyme and reflects the substrate concentration at which the reaction rate is half of its maximum value. It does not depend on the concentration of substrate directly.
Km is directly proportional to enzyme concentration: This is false. Km is independent of enzyme concentration. The enzyme concentration affects the overall rate of the reaction but not the Km.
Km is indirectly proportional to substrate concentration: This is false. Km is a constant specific to the enzyme-substrate interaction and does not change with varying substrate concentrations.
Km has no relation to substrate concentration: This is true. Km is a constant for each enzyme and does not change with varying substrate concentrations. It is a measure of the enzyme's affinity for the substrate. Thus, the correct answer is Km has no relation to substrate concentration (4).