The Allosteric Effect of Fructose Bisphosphate on Muscle Pyruvate Kinase Studied by Infrared Spectroscopy

What is it about?

The conformational change of phosphenolpyruvate (PEP) binding to pyruvate kinase was about twice as large in the presence of the allosteric effector fructose bisphosphate (FBP) as in its absence, which is ascribed to a higher occupancy of the closed state of the enzyme ligand complex. No such effect is observed when the catalytic Mg2+ is replaced by Mn2+. Instead, PEP binding induces the larger conformational change already in the absence of FBP.

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Why is it important?

Allostery is an important control mechanism to modulate the activity of enzymes. In the case studied here, the allosteric effect depended on the divalent ion present in the sample.