THE PRESENCE OF A GLUCOSE-DERIVED MAILLARD REACTION-PRODUCT IN THE HUMAN LENS

Pyrraline is an advanced Maillard reaction product formed by the non-e nzymatic reaction initiated by glucose with lysine residues on protein s. This reaction involves an intermediate, 3-deoxyglucosone, concentra tion of which is shown to be elevated in plasma and lenses during diab etes. Bovine lens alpha crystallins incubated with 3-deoxyglucosone sh owed that pyrraline formation was a major modification and its quantif ication by two different methods revealed time-dependent accumulation. Pyrraline was quantified in normal, senile cataractous and diabetic l enses. Although a wide variation was observed, the mean value in catar actous lenses (mean +/- S.E.: 48.4 +/- 12.67 pmol/mg protein) was high er than in age-matched normal lenses (30.9 +/- 10.26 pmol). Surprising ly, in diabetic lenses, the mean value was loser than normal lenses (2 8.4 +/- 15.3 pmol). These results suggest that glucose-specific advanc ed Maillard products occur in the human lens and such modifications ma y play a role in lens aging and cataract formation.