Identify one molecule that could potentially act as a feedba

Identify one molecule that could potentially act as a feedback inhibitor of citrate synthase, the enzyme that carries out the first step of the citric acid cycle. Explain why this molecule was picked.

Solution

The enzyme is inhibited by high ratios of

ATP:ADP,

acetyl-CoA:CoA,

and NADH:NAD,

as high concentrations of ATP, acetyl-CoA, and NADH.

They show that the energy supply is high for the cell.

It is additionally repressed by succinyl-CoA, which looks like Acetyl-coA and goes about as an uncompetitive inhibitor.

Citrate synthase has three key amino acids in its dynamic site (known as the synergist set of three) which catalyze the change of

a) acetyl-CoA [H3CC(=O)SCoA]

and

b) oxaloacetate into citrate

and

c) HSCoA in an aldol condensation reaction.