Question

Which of the following best describes the role of fructose-2,6-bisphosphate (FBP) in liver cells? a. FBP is a potent allosteric activator of fructose bisphosphatase and an inhibitor of phosphofructokinase b. It is an intermediate in gluconeogenesis c. It is an intermediate in both glycolysis and gluconeogenesis d. FBP is a potent allosteric activator of phosphofructokinase and an inhibitor of fructose bisphosphatase e. It is an intermediate in glycolysis

Answer 1

Answer:

The correct answer is d FBP is a potent allosteric activator of phosphofructokinase and inhibitor of fructose bisphosphatase

Explanation:

Fructose-2,6 bisphosphate is formed from fructose-6-phosphate by the catalytic activity of phosphofructokinase 2 .The so formed fructose-2,6- bisphosphate activates the enzyme phosphofructokinase 1 resulting in conversion of fructose-2,6-bisphosphate to fructose -1,-bisphosphate.This is an important example of feed forward activation.

   On the other hand FBP act as an inhibitor of fructose bisphosphatase thus slowing down the rate of gluconeogenesis.