Question

Explain briefly why the carbonyl group at C2 of fructose-­1,6-­bisphosphate is necessary for carbon-­carbon bond cleavage in step 4 of glycolysis.

Answer 1

This is a Committed step. The two C3 species generated in the next step are energetically equivalent! Both halves of the fructose are phosphorylated at this point (C1 and C6). This is driven by enzyme aldolase. In the next step the purpose of Isomerization of triose phosphate is

1. To convert the dihydroxyacetone phosphate (ketone) to a Glyceraldehyde 3-phosphate (aldose)
2. It allows the formation of a second pair of ATP molecules.

Hence in conclusion carbonyl group at C2 of fructose-­1,6-­bisphosphate is necessary for carbon-­carbon bond cleavage in step 4 of glycolysis because of Triose phosphate isomerase decreases ΔG for the step in glycolysis catalyzed by aldolase through rapid removal of dihydroxyacetone phosphate.

Thank You So Much! Please Rate this answer as you wish.