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Abstract

Glycation, the nonenzymic interaction of sugars with proteins is known to play a key role in complications of many pathophysiological processes. Glycation by sugars is directed against the positively charged residues in the protein, namely arginine and lysine. It is an undesirable phenomenon and result in progressive loss of function of biological system. Glycated proteins are tolerated in the body compartment, as breakdown and replacing them amounts to spending extra energy. So the glycated protein to exist in body compartment should resort to compensatory mechanisms that resist the effects of glycation. The charge regulation is such a process, which resist the change in net charge due to glycation. Thus the increase in the net charge of the protein, results in increased negative potential on the surface of the protein which increases the local concentration of H+ ions around the histidine residues in proteins there by affecting their ionization. Since glycation is inevitable process, I hypothesise yet another possible evolutionary role of histidine in proteins to resist change in net charge arising due to deleterious modification.