Which of the following elements is involved in the mechanism of chymotrypsin?
A)deprotonation of an active site Asp residue by His to start the reaction
B)formation of an acyl-enzyme intermediate that must be hydrolyzed to complete the reaction
C)stabilization of the positively charged His by a Gln residue
D)direct deprotonation of water by His to generate a hydroxide ion for initiation of the reaction

Question

Quizplus · Accepted Answer

Chymotrypsin involves the formation of an acyl-enzyme intermediate, where the substrate is covalently bound to the enzyme, that must be hydrolyzed to complete the reaction. This mechanism is characteristic of serine protease enzymes like chymotrypsin. Option A is partially correct but not complete as it describes a step in the mechanism but not specifically related to chymotrypsin. Option C is not correct as chymotrypsin does not have a Gln residue involved in its active site. Option D is incorrect as the hydroxide ion is generated by a water molecule, not directly by His.

Which of the Following Elements Is Involved in the Mechanism