Experiments on the bacterial serine protease subtilisin show that even when all three residues of the catalytic triad are mutated,the catalytic rate of the enzyme is still 3000 times the uncatalyzed reaction rate.Which mode of catalysis is likely responsible for this remaining catalytic activity?
A)Acid-base catalysis.
B)Covalent catalysis.
C)Transition-state stabilization.
D)Hydrophobic effects.

Question

Quizplus · Accepted Answer

Transition-state stabilization is the mode of catalysis that involves stabilizing the transition state of a reaction, therefore lowering the activation energy required for the reaction to occur. This can enhance the reaction rate by several orders of magnitude, as seen in the case of subtilisin where even when all three residues of the catalytic triad are mutated, there is still a catalytic rate that is 3000 times the uncatalyzed reaction rate. Acid-base catalysis involves transferring protons to or from a substrate to facilitate the reaction, while covalent catalysis involves the formation of a covalent bond between the enzyme and the substrate. Hydrophobic effects do not typically serve as a mode of catalysis.

Experiments on the Bacterial Serine Protease Subtilisin Show That Even