Calpain II in human lens.

摘要: The purposes of the current study were to: determine if human lenses contain calpain II (EC.34.22.17) activity, measure effect aging and anatomical location on lens endogenous inhibitor calpastatin. Both enzymatic immunologic assays indicated that contained activity. Calpain activity was highest in cortex from young donors, lowest nucleus aged lenses, where it sometimes nondetectable. In some cases, persisted donors greater than 70 years age. Human also (calpastatin) excess over Calpastatin did not decrease during aging. Although approximately 3% found rat may still be a major endopeptidase lenses. Demonstration suggested could involved both maturation cataract formation. Invest Ophthalmol Vis Sci 30:269-275,1989 Calpains are nonlysosomal proteases containing cysteine residue active site, having neutral pH optima, an absolute dependence calcium for catalytic 1 Two types exist most tissues, one requiring fimolar activation (calpain I), mmolar II). 2 precise biological function these ubiquitous different tissues is clear. However, they cause limited proteolysis resulting protein kinase C platelets neutrophils, degradation membrane cytoskeletal proteins erythrocytes, processing neurofilament microtubule neuropeptides brain, metabolic turnover myonbrils muscle. 3