In the pathway A + B $\rightarrow$C + D, enzyme X facilitates the reaction.If compound D is further metabolized through a series of steps to form compound Z, and compound Z inhibits enzyme X, one could conclude that

Question

Quizplus · Accepted Answer

Enzyme X is inhibited by compound Z, which is formed from the metabolism of D. This suggests that there is feedback inhibition occurring, as the product of the pathway is inhibiting the enzyme that catalyzes an earlier step. Therefore, choice D is the best answer. Choice A is incorrect because there is no evidence to suggest that enzyme X is subject to feedback stimulation. Choice B is incorrect because D is not an allosteric activator, but rather a substrate in the pathway. Choice C is incorrect because compound Z is an inhibitor of the first reaction, not a competitive inhibitor. Choice E is incorrect because coenzymes typically act as helpers or carriers of chemical groups, and do not serve as substrates in the reaction like compound D.

In the Pathway a + B →\rightarrow→ C + D, Enzyme X Facilitates the Reaction

In the Pathway a + B $\rightarrow$ C + D, Enzyme X Facilitates the Reaction