Studies on the Amadori rearrangement in a model system: chromatographic isolation of intermediates and product.

The pH profile of the reaction of glyceraldehyde with either valylhistidine or alanylhistidine exhibits an optimum near pH 6.5. One of the intermediates in the reaction, the Schiff base (aldimine), can be readily detected on an amino acid analyzer. The product of the reaction, the ketoamine formed after Amadori rearrangement of the aldimine, has been isolated by chromatography on Dowex 50. Its structure has been established by elemental analysis, amino acid analysis, and the relative amounts of carbonyl and histidine moieties. These chromatographic systems should facilitate studies on the mechanism of this reaction as it relates to peptides and proteins.