Question

Which of the following types of enzymes are usually subjected to direct feedback inhibition by an intracellular metabolite?

A. Enzymes catalyzing the last step in a catabolic pathway
B. Enzymes catalyzing the last step in a biosynthetic pathway
C. Enzymes catalyzing the first step in a biosynthetic pathway
D. Enzymes localized in the extracellular matrix
E. Enzymes localized in lysosomes.

Answer 1

Option (C), Enzymes catalyzing the first step in a biosynthetic pathway are typically subject to direct feedback inhibition by end products of that pathway to regulate production and maintain homeostasis.

Step-by-step explanation:

The types of enzymes that are usually subjected to direct feedback inhibition by an intracellular metabolite are those catalyzing the first step in a biosynthetic pathway. Feedback inhibition serves as a regulatory mechanism where the end product of a metabolic pathway inhibits an earlier enzyme, often the first committed enzyme in the pathway, to regulate its own further production.

This elegant cellular strategy ensures efficient resource use and prevents the overaccumulation of pathway products. Inhibiting the first enzyme in the pathway can slow down the entire sequence of reactions, thus conserving resources and energy that would otherwise be spent on producing an abundance of the end product.