Sites of glycation of beta B2-crystallin by glucose and fructose.

We determined the sites of glycation of bovine beta B2-crystallin by glucose and fructose. After incubation with glucose or fructose, glycated tryptic peptides were purified by affinity chromatography/reverse-phase HPLC and identified by electrospray ionization mass spectrometry (ESIMS). The results gave evidence of glycation at lysine 10, 75, 100, 107, 120, 139, 167 and 171 by both glucose and fructose, while glycated lysine 119 and 47 or 67 were detected only after fructosylation. We conclude that glucose and fructose have similar glycation specificity.