MODEL STUDIES ON THE PHOTOCHEMICAL PRODUCTION OF LENTICULAR FLUOROPHORES

摘要: With aging, human lens proteins accumulate fluorophores having blue and green emissions. Model studies were undertaken to determine the role of 3-hydroxykynurenine (3-HK) its glucoside (3-HKG) in photochemical production those fluorophores. Experiments carried out using 10−3M 3-HK solutions presence or absence glycine (1M), which was used mimic environment lens. The photolyzed (transmission above 295 nm) for various periods time while loss starting material formation fluorescent photoproducts (blue emission at 470 nm, 520 monitored fluorescence UV-visible spectroscopy thin-layer high-pressure liquid chromatography analysis. Several parameters varied such as oxygen tension addition free radical scavenger, penicillamine. photolytic occurred approximately 5-10 times faster than presence. Conversely, formed irradiated containing but not with photolysis alone. fluorophore first appeared then be photochemically converted one, rate latter increasing an increase UV dosage oxidizing conditions. penicillamine drastically reduced both fluorophores. Both appear result from induced covalent attachment glycine. In lens, these reactions can explain age-related 3-HKG concomitant covalently attached proteins, probably via amino group lysine.