試題詳解

38. Fructose 2,6-bisphosphate (F26BP) is a potent regulator of glycolysis and gluconeogenesis. Which of the following descriptions is       correct      ?
(A) The cellular concentration of F26BP is determined by the relative rates of its synthesis by fructose 2,6-biphosphatase (FBPase-2) and breakdown by phosphofructokinase-2 (PFK-2).
(B) F26BP is an allosteric activator for the enzyme fructose 1,6-biphosphatase (FBPase-1). It activates FBPase-1 and stimulates glycosis in liver.
(C) Insulin increases the cellular concentration of F26BP by activating a cAMP-dependent kinase that phosphorylates PFK-2.
(D) Phosphorylation of the bifunctional enzyme PFK-2 and FBPase-2 inhibits PFK-2 activity and stimulates FBPase-2 activity, leading to breakdown of F26BP.
(E) An elevated level of glucagon or epinephrine increases the cellular concentration of F26BP.