What describes the functional relationship between an enzyme and a substrate during feedback inhibition?

The functional relationship between an enzyme and a substrate during feedback inhibition is primarily described by allosteric inhibition. In this process, an end product of a metabolic pathway can bind to an allosteric site on an enzyme that catalyzes an earlier step in the pathway. This binding changes the shape or activity of the enzyme, inhibiting its function.

Allosteric inhibition serves as a regulatory mechanism to prevent the overproduction of the end product. This ensures that the cell maintains homeostasis and uses energy efficiently by stopping the pathway when there is sufficient product.

Although competitive and non-competitive inhibition are relevant forms of enzyme regulation, they do not specifically describe the feedback inhibition mechanism where the end product itself plays a direct role in regulating the enzyme's activity. Substrate saturation refers to the scenario where all active sites on the enzyme are occupied by substrates, leading to a maximum reaction rate, but it does not involve the feedback mechanism described in the question. Therefore, allosteric inhibition accurately captures the essence of feedback inhibition involving the functional relationship between an enzyme and a substrate.