Direct approach to identification, at the molecular level, of modified proteins in human nuclear cataractous lenses: beta-crystallin is a component of the urea-insoluble protein fraction.
In an effort to elucidate the molecular changes which take place in the human lens with the onset of nuclear cataract, the urea-insoluble protein fraction, solubilized with dithiothreitol, was digested with trypsin. Tryptic peptides separated by HPLC, were examined by both mass spectrometry and Edman degradation. A pentapeptide Gly-Glu-Tyr-Pro-Arg which is contained within the beta-crystallin sequence was isolated. This finding provides direct evidence that beta-crystallin is present in the urea-insoluble protein fraction which is known to be characteristic of human nuclear cataract lenses.
O'Hair
R A
RA
Australian Cataract Research Foundation, University of Wollongong, N.S.W.
Sheil
M M
MM
Truscott
R J
RJ
D000595:Amino Acid Sequence; D002386:Cataract / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D003459:Crystallins / Q000302:isolation & purification / Q000378:metabolism*; D006801:Humans; D007907:Lens Nucleus, Crystalline / Q000378:metabolism*; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000302:isolation & purification / Q000378:metabolism; D012995:Solubility; D014508:Urea
D003459:Crystallins; D009842:Oligopeptides; D014508:Urea