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The effects of carnosine and related compounds (CRCs) including anserine, homocarnosine, histidine, and β?alanine on monosaccharide autoxidation and H2O2 formation were investigated. The incubation of CRCs with D-glucose, D-glucosamine, and D, L-glyceraldehyde at 37?C increased the absorption maxima at 285 nm, 273 nm, and 290∼330 nm, respectively. D, L-glyceraldehyde was the most reactive sugar with CRCs. The presence of copper strongly stimulated the reaction of carnosine and anserine with D-glucose or D-glucosamine. Carnosine and anserine stimulated H2O2 formation from D-glucose autoxidation in a dose-dependent manner in the presence of 10 μM Cu (II). The presence of human serum albumin (HSA) decreased their effect on H2O2 formation. Carnosine and anserine has a biphasic effect on α?ketoaldehyde formation from glucose autoxidation. CRCs inhibited glycation of HSA as determined by hydroxymethyl furfural, lysine residue with free ε?amino group, and fructosamine assay. These results suggest that CRCs may be protective against diabetic complications by reacting with sugars and protecting glycation of protein.
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