Which of the following intermediates is an allosteric activator of pyruvate kinase?

a. glucose-6-phosphate

b. fructose-1,6-bisphosphate

c. pyruvate

d. glyceraldehyde-3-phosphate

b. fructose-1,6-bisphosphate

Explanation:

Pyruvate kinase is involved in last step of the process of glycolysis. The enzyme catalyzes transfer of the phosphate group from the phosphoenolpyruvate PEP to ADP and thus forming one molecule of the pyruvate and also, one molecule of ATP.

Glycolysis pathway is highly regulated at the three steps which are:

Phosphorylation of the glucose by the enzyme, hexokinase. Phosphorylation of the fructose-6-phosphate by the enzyme, phosphofructokinase. Transfer of phosphate from phosphoenolpyruvate to ADP by the enzyme, pyruvate kinase.

All three of the reactions are irreversible in nature iunder wild-type conditions and thus have large negative free energy which are responsible for regulation of glycolysis pathway.

The activity of the enzyme, pyruvate kinase is mostly regulated by the allosteric effectors, by the covalent modifiers and also by the hormonal control.

The most significant regulator for pyruvate kinase is fructose-1,6-bisphosphate that serves as allosteric effector for enzyme.