Consider the biochemical pathway used to synthesize the amino acid proline. An increase in the concentration of proline will most likely lead to___________.a. a decrease in proline production. b. increased breakdown of proline. c. a further increase in proline production. d. no change in the rate of proline production.

This occurs as a result of the feedback inhibition which is a cellular control mechanism where enzyme activity is inhibited by the enzyme’s end product thus allowing cells to regulate how much of an enzyme’s end product is produced. Typically, feedback inhibition acts on the first enzyme unique to a given pathway. For example, in the case of amino acid production, an amino acid may act as an inhibitor for the first enzyme in the pathway whose purpose is making more of that amino acid.

Feedback inhibition is usually achieved through an “allosteric site” – a site on an enzyme that changes the shape of the enzyme, and subsequently the behavior of the active site, therefore, in feedback inhibition, binding of the end product to this site slows down or stops the enzyme’s activity so that little or no new end product is produced causing a product drop