BIOCHEM Questions

Question

which enzyme is regulated by a feedforward mechanism by its own substrate

PK

Hexokinase

PFK

PDH

Isocitrate dehydrogenase

Answer 1

PK, or pyruvate kinase, can be regulated by a feed-forward mechanism. PK catalyzes the conversion of phosphoenolpyruvate to pyruvate and ATP. PK is the last step in glycolysis, in which pyruvate, ATP, and electron carriers are generated from glucose. Fructose 1,6 bisphosphate (F1,6BP) is molecule that creates the feed-forward mechanism on PK. F1,6BP is produced in one of the earlier steps in glycolysis, and it is an allosteric activator of PK. This mechanism is known as “feed forward” because a product from an earlier step in the process activates a later step.