Question

A series of enzymes catalyze the reaction X Y Z A. Product A binds to the enzyme that converts X to Y at a position remote from its active site. This binding decreases the activity of the enzyme.With respect to the enzyme that converts X to Y, substance A functions asa. a coenzyme.b. an allosteric inhibitor.c. the substrate.d. an intermediate.e. a competitive inhibitor.

Answer 1

Answer:

Option B, an allosteric inhibitor.

Explanation:

As the enzyme activity decreases, it is not possible for A to be a coenzyme (most likely would increase the enzyme activity), a substrate (increases activity of enzyme by Le Chatler's principle) or an intermediate (no effect). A is unlikely to be a competitive inhibitor as this would not decrease the activity of the enzyme, only  reduce the rate of conversion of substrate to product. A is most likely an allosteric inhibitor which binds to another site on the enzyme (other than the active site), resulting in a change in conformation of the enzyme which reduces the enzymatic activity.