Potassium iodide and acrylamide fluorescence quenching studies on gamma-crystallins of human lenses in development and aging.
gamma 1-, gamma 2- and gamma 3-crystallin (corresponding to gamma s-, gamma C- and gamma D-crystallin respectively) of human fetal, 2 year and 20+ year old lenses are separated by Sephadex gel chromatography. Iodide and acrylamide are used to quench the tryptophane fluorescence of sub-gamma-crystalline fractions and Ksv and fa values are calculated. The results show that iodide has no clear quenching effects on all gamma-crystallins, the quenching effects of acrylamide on the tryptophan fluorescences of gamma 1-, gamma 2- and gamma 3-crystallin from lenses of the same age have little differences, and the quenching rates of tryptophane fluorescences of gamma 1-crystallin decreases and that of gamma 2- and gamma 3-crystallin increase with age. These results indicate that all tryptophan residues in these three gamma-crystallins lie in hydrophobic environments of molecule and their exposure degree is in the order gamma 2 < gamma 3 < gamma 1. The tryptophan exposure of gamma 2 and gamma 3 increase (gamma 2 > gamma 3) and of gamma 1 decrease with age. The age related change of gamma 1 may be related to the changing of structure or containing of new constituents. Although the tryptophan exposure in gamma 3 is higher than that in gamma 2, the change of structure with age in gamma 2 is more prominent than in gamma 3.
Li
S
S
National Ophthalmological Laboratories, Ministry of Public Health, China.
Wu
K
K
Liang
S
S
Pan
S
S
D000178:Acrylamides; D000328:Adult; D000367:Age Factors; D002675:Child, Preschool; D003459:Crystallins / Q000737:chemistry*; D005333:Fetus; D006801:Humans; D007908:Lens, Crystalline / Q000737:chemistry* / Q000196:embryology; D011193:Potassium Iodide; D013050:Spectrometry, Fluorescence
D000178:Acrylamides; D003459:Crystallins; D011193:Potassium Iodide