Calcium-induced opacification and proteolysis in the intact rat lens.

摘要: When intact rat lenses were incubated in artificial aqueous humor the presence of 1 mM calcium and a sulfhydryl reagent p-chloromercuriphenyl sulfonate (pCMPS) visible annular opacity developed within 4 hours. Combined photographic ion-sensitive microelectrode investigations demonstrated that subsequent linear increase opacification was accompanied by an internal free calcium. Opacities not observed absence either pCMPS or Gel electrophoresis soluble urea-soluble fractions from exposed to for periods up 14 hours showed no evidence crystallin degradation only minor proteolysis cytoskeletal proteins. under identical conditions, but with 5 calcium, degree increased approximately 8 then remained constant. A progressive loss proteins which correlated further such incubation, when approached mM, most spectrin vimentin present cortex lens had disappeared. An unidentified 110-kilodalton protein also disappeared These results indicate calcium-dependent enzymes as calpain may play significant role regulation metabolism lens. cytoskeleton/membrane/crystallin interaction calcium-induced is discussed.