Question

Which of the following statements are correct for the Kcat?
A. It is also called turnover number
B. Specificity constant of an enzyme can be calculated from its Kcat and Km
C. Kcat is calculated from the Vmax and number of substrate binding site of an enzyme
D. It can also be calculated from initial substrate concentration and enzyme concentration only
Choose the correct answer from the options given below:

• A. A only
• B. A, B and C only
• C. B, C and D only
• D. A, C and D only

Hint:

Kcat: turnover number.
Specificity constant: Kcat/Km.
Kcat = Vmax [E]\(_t\).

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Kcat is the turnover number of an enzyme.
It describes the catalytic efficiency.

Step 2: Key Formula or Approach:
Kcat = Vmax [E]\(_t\), where [E]\(_t\) is total enzyme concentration.
Specificity constant = Kcat Km.

Step 3: Detailed Explanation:
A. Kcat is called turnover number - correct.
B. Specificity constant = Kcat/Km - correct.
C. Kcat = Vmax [E]\(_t\) (total enzyme concentration) - correct.
D. Kcat cannot be calculated from initial substrate concentration and enzyme concentration only.
Thus, A, B, and C are correct.

Step 4: Final Answer:
The correct statements are A, B, and C.
Hence, the correct option is (B).