Question

BIOCHEM

Compare and contrast how fructose‐1,6‐bisphosphatase and phosphofructokinase are regulated

in response to energy charge. What specific allosteric effectors are involved? What is meant by

reciprocal regulation.

Pyruvate kinase is also regulated allosterically by fructose‐1,6‐bisphosphate. Explain the

rationale for this regulation. Do these compounds stimulate or inhibit pyruvate kinase?

Answer 1

AMP excites phosphofructokinase, while ATP and citrate hinder it. However, fructose 1,6-bisphosphatase is hampered by AMP and activated by citrate. A towering level of AMP signifies that the energy charge is small and signals the requirement for ATP production. Conversely, elevated levels of ATP and citrate indicate that the energy charge is high and that biosynthetic intermediates are plentiful.

RECIPROCAL REGULATION

Pyruvate kinase has been allosterically activated by Fructose 1,6 bisphosphate and allosterically inactivated by ATP and alanine.