Which of the following statements are correct for Km - Michaelis Menten Constant?
(A). Km has unit of concentration.
(B). Km is equal to substrate concentration.
(C). Quantitative relationship between the initial velocity, \(\text{V}_0\) and the maximum velocity, \(\text{V}_{\max}\).
(D). Regulatory enzymes obey Michaelis Menten constant.
Choose the correct answer from the options given below:
Show Hint
A lower \(\text{K}_m\) value indicates a higher affinity of the enzyme for its substrate, meaning less substrate is needed to half-saturate the enzyme's active sites.
Step 1: Understanding the Concept:
The Michaelis constant (\(\text{K}_m\)) is a key parameter in enzyme kinetics that describes the affinity of an enzyme for its substrate. Step 2: Detailed Explanation:
- Statement A is correct: \(\text{K}_m\) is expressed in units of concentration (e.g., millimolar or micromolar).
- Statement B is correct: \(\text{K}_m\) is defined as the substrate concentration at which the reaction rate is exactly half of its maximum velocity (\(\text{V}_0 = \frac{1}{2} \text{V}_{\max}\)).
- Statement C is correct: \(\text{K}_m\) is a key parameter in the Michaelis-Menten equation, which quantitatively relates initial reaction velocity (\(\text{V}_0\)) to maximum velocity (\(\text{V}_{\max}\)) as a function of substrate concentration.
- Statement D is incorrect: Regulatory (allosteric) enzymes do not follow Michaelis-Menten kinetics. They show a sigmoidal (S-shaped) saturation curve rather than the classic hyperbolic curve.
- Therefore, only statements (A), (B), and (C) are correct. Step 3: Final Answer:
The correct combination is (A), (B) and (C) only.
