Zymogens are not enzymatically active because
A)the active site amino acids have been mutated.
B)they have not yet bound the proper cofactor.
C)their environment has the wrong pH.
D)they are not yet shaped such that essential proximity and orientation catalysis can occur.
E)None of the above is correct.

Question

Quizplus · Accepted Answer

Zymogens are synthesized and secreted in an inactive form. The reason behind their inactivity is that they are not shaped in such a way that essential proximity and orientation catalysis can occur. The zymogens require the cleavage of one or more peptide bonds to become active, and this cleavage contributes to the formation of the active site. The cleavage changes the enzyme's shape, allowing it to interact with substrates and cofactors, making it enzymatically active. Therefore, option D is correct, and the other options are incorrect.

Zymogens Are Not Enzymatically Active Because