title: The presence of a glucose-derived Maillard reaction product in the human lens.
abstract: Pyrraline is an advanced Maillard reaction product formed by the non-enzymatic reaction initiated by glucose with lysine residues on proteins. This reaction involves an intermediate, 3-deoxyglucosone, concentration of which is shown to be elevated in plasma and lenses during diabetes. Bovine lens alpha crystallins incubated with 3-deoxyglucosone showed that pyrraline formation was a major modification and its quantification by two different methods revealed time-dependent accumulation. Pyrraline was quantified in normal, senile cataractous and diabetic lenses. Although a wide variation was observed, the mean value in cataractous lenses (mean +/- S.E.: 48.4 +/- 12.67 pmol/mg protein) was higher than in age-matched normal lenses (30.9 +/- 10.26 pmol). Surprisingly, in diabetic lenses, the mean value was lower than normal lenses (28.4 +/- 15.3 pmol). These results suggest that glucose-specific advanced Maillard products occur in the human lens and such modifications may play a role in lens aging and cataract formation.
authors.affiliation: Center for Vision Research, Department of Ophthalmology, Case Western Reserve University, Cleveland, OH 44106, USA.
authors.forename: R H
authors.initials: RH
authors.lastname: Nagaraj
authors.forename: C
authors.initials: C
authors.lastname: Sady
mesh_terms: D000818:Animals; D002386:Cataract / Q000378:metabolism; D002417:Cattle; D003459:Crystallins / Q000737:chemistry / Q000378:metabolism; D003847:Deoxyglucose / Q000031:analogs & derivatives* / Q000378:metabolism; D003920:Diabetes Mellitus / Q000378:metabolism; D006801:Humans; D007908:Lens, Crystalline / Q000737:chemistry / Q000378:metabolism*; D015416:Maillard Reaction; D009646:Norleucine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D011487:Protein Conformation; D011758:Pyrroles / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D003459:Crystallins; D011758:Pyrroles; C059571:2-formyl-5-(hydroxymethyl)pyrrole-1-norleucine; D009646:Norleucine; D003847:Deoxyglucose; C016350:3-deoxyglucosone