Which of the following statements correctly indicate (s) the role of ATP or ADP as an allosteric regulator? Assume that the supply of energy for cellular processes is adjusted to meet cellular demand for energy.

A) ATP is an allosteric inhibitor of catabolic pathways.

B) ADP is an allosteric activator of catabolic pathways.

C) ATP is an allosteric activator of anabolic pathways.

D) A and B only

E) A, B, and C

E. A, B and C

Explanation:

Catabolic pathways breakdown the complex compounds into simpler substances. These pathways are mostly exergonic and the released energy is stored in the form of ATP. Therefore, the increased cellular concentration of ADP serves as an allosteric activator of enzymes of catabolic pathways. On the other hand, the increased cellular concentration of ATP inhibits the enzymes of catabolic pathways as the cell's energy needs are already met.

Anabolic pathways form complex compounds from simpler substances. These pathways are mostly endergonic in nature. ATP hydrolysis provides energy for anabolic reactions. Therefore, ATP serves as an allosteric activator for the enzymes of anabolic pathways.