[Comparison of free non-tryptophan fluorescent substances in water-soluble fraction of brunescent and non-brunescent human cataract].
We compared the concentrations of protein-unbound non-tryptophan fluorescent substances in the water-soluble fraction between non-brunescent (NBr) and brunescent (Br) human cataractous lens nuclei. Lens nuclei (NBr, 22 eyes: Br, 9 eyes) from non-diabetic patients, obtained by extracapsular cataract extraction, were individually homogenized and centrifuged. The supernatants were subsequently ultra-dialyzed and assessed by high pressure liquid chromatography. 3-Hydroxykynurenine-O-beta-glucoside (3-HKG) as well as an unidentified fluorescent substance was detected. While the concentrations of the former substance did not significantly differ between the NBr and the Br nuclei (NBr, 0.55 +/- 0.49 mumol/g wet weight: Br, 0.90 +/- 0.64 mumol/g wet weight; p > 0.1), the concentration of the latter substance was significantly greater in the Br nuclei than in the NBr nuclei (NBr, 2.2 x 10(3) +/- 5.4 x 10(3) AU/g wet weight: Br, 1.4 x 10(5) +/- 1.1 x 10(5) AU/g wet weight; AU: area unit, p < 0.01). An incubation of the dialysate with beta-glucosidase eliminated the peak corresponding to the latter substance. These results suggest that an unidentified protein-unbound fluorescent substance, which is presumably a beta-glucoside, in the lens nuclei is related to the coloration of human lens nuclei.
Iwase
T
T
Department of Ophthalmology, Kanazawa University School of Medicine, Japan.
Shirao
E
E
Shirao
Y
Y
Matsukawa
S
S
Fukuda
R
R
D002386:Cataract / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D005453:Fluorescence; D005960:Glucosides / Q000378:metabolism*; D006801:Humans; D007737:Kynurenine / Q000031:analogs & derivatives* / Q000378:metabolism; D007908:Lens, Crystalline / Q000378:metabolism*; D012995:Solubility; D014364:Tryptophan
D005960:Glucosides; C029366:hydroxykynurenine glucoside; D007737:Kynurenine; D014364:Tryptophan