Question

Suppose that an arginine residue in the active site of an enzyme was mutated to alanine. As expected, the alanine mutant was inactive, suggesting that the arginine residue was critical to the catalytic mechanism. Which mutation is most likely to restore wild‑type level of activity to the alanine mutant?
a. A to M
b. A to S
c. A to K
d. A to Y
e. A to E

Answer 1

Answer:

c. A to K

Explanation:

If the alanine mutation is restored to K or lysine residue, most likely the wild type level of activity can be restored. This is because, arginine and lysine have -NH2 as the functional group. So, functional similarity of arginine can be expected from lysine as well.

Hence the correct option is c that is A to K.