Change of water-soluble-protein, urea-soluble-protein and membrane intrinsic protein in human senile cataract.
OBJECTIVE
To analyze the change of water-soluble-protein (WSP), urea-soluble-protein (USP) and membrane intrinsic protein (MIP) in human senile cataract.


METHODS
The water-soluble-fractions (WSF) were prepared basically according to the method of Kibbelear, et al. But in this study, 5 mmol/L B-mercaptoethanol was added to the buffer solution. The urea-soluble-fractions (USF) were prepared basically according to the method of Kibbelear, et al. Lens fiber cell membranes were purified basically according to the method of Russell, et al. SDS-PAGE were performed according to the procedure of Laemmili, et al. using resolving gel 13% and 3% stacking gel.


RESULTS
The WSP was fractionated into HM+ alpha-, beta(1-3)- and gamma-crystallin components. In nuclear cataractous lenses HM+ alpha- and B-crystallin increase, while r-crystallin decrease. The USP from clear lenses contains mainly alpha beta chains of 22KD, whereas in cataractous lenses, especially in nuclear cataractous lenses, the relative amount of the 28- and 23KD polypeptide (the components of beta-crystallin) increased markedly. Lens fiber cell MIP, clear lens and cataract lens contained the main polypeptide of 27KD (MIP) and 23KD (MP23).


CONCLUSIONS
The water-insoluble protein, whether in quantity or in quality, plays an important role in cataract formation.
Zhao
H
H
Department of Biochemistry, Xuzhou Medical College, China.
Hu
S
S
Ren
X
X
Yang
J
J
Sun
L
L
D000368:Aged; D020346:Aquaporins; D002386:Cataract / Q000378:metabolism*; D003459:Crystallins / Q000378:metabolism*; D005136:Eye Proteins / Q000378:metabolism*; D006801:Humans; D007908:Lens, Crystalline / Q000737:chemistry / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000378:metabolism*
D020346:Aquaporins; D003459:Crystallins; D005136:Eye Proteins; D008562:Membrane Glycoproteins; C030328:aquaporin 0