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Biochemistry

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Glycolysis: Regulation of Phosphofructokinase

BIOCHM-WCDZKI

The glycolytic, regulatory enzyme Phosphofructokinase-1 (PFK-1) catalyzes the phosphorylation of Fructose-6-P (F6P) to Fructose-1,6-bisphosphate (FBP) using ATP. It is the first committed step of glycolysis.

The corresponding enzyme in gluconeogenesis, Fructose-1,6-Bisphosphatase-1 (FBPase-1), catalyzes the reverse reaction. Both PFK-1 and FBPase-1 are reciprocally regulated by several allosteric inhibitors and activators.

Taking into consideration the regulation of glycolysis and gluconeogenesis relative to other metabolic pathways, identify which ONE of the following correctly identifies an allosteric effector of PFK-1 or FBPase-1 as an inhibitor or activator.

A

Low concentrations of ATP allosterically inhibit PFK-1 and activate FBPase-1.

B

AMP allosterically inhibits PFK-1.

C

High concentrations of ATP allosterically inhibit PFK-1.

D

ADP allosterically activates FBPase-1.

E

High concentrations of citrate allosterically activate PFK-1.