Influence of pH and phosphate ions on the kinetics of enolisation and degradation of fructosamines. Studies with the model fructosamine, N epsilon-1-deoxy-D-fructos-1-yl-hippuryl-lysine.

: Investigation of the rate of enolisation and degradation of the model peptide fructosamine N epsilon-1-deoxy-D-fructos-1-yl-hippuryl-lysine and related monosaccharides revealed the fructosamine to be activated towards enolisation but little of the enolic intermediates proceeded to form advanced glycation endproducts. For the oxidative degradation of monosaccharides, enolisation was rate-limiting. Enolisation of the fructosamine was promoted by hydroxide, phosphate and pyrophosphate buffer ions but not directly influenced by the protonation state of the fructosyl amino group. The formation of advanced glycation end-products may be greatly enhanced in the presence of suitable catalysts (trace metal ions) of the degradation of fructosamine-derived enolic intermediates.