Protein-Thiol Mixed Disulfides and Thioltransferase in the Lens

摘要: Oxidative stress is considered an important factor in human senile cataract formation, fact many consider it as the primary mechanism that responsible for cataracts. damage can affect intracellular proteins well lens membranes. We have studied oxidative to involve sulfhydryl groups are most sensitive stress. In cataracts characterized by increase protein disulfides (PS SP). Our studies suggest synthesis of PSSP preceded formation protein-thiol mixed disulfide between and oxidized glutathione (PSSG) or cysteine (PSSC). A normal contains nanomole quantities PSSG PSSC, at level 2-5% free (GSH). However, these compounds be elevated extensively cataractous lenses stress-induced animal lenses. The latter include induced hyperbaric oxygen, naphthalene, ultraviolet light, diquat hydrogen peroxide. Even Emory mouse cataract, a genetic occurring aging mice, significant amount disulfides. If oxidant removed from environment, disulfides, particular PSSG, spontaneously return level. This recovery process age-dependent but not rat lens. speculate this may mediated thioltransferase, redox regulating enzyme known other tissues dethiolate recently found ocular tissues. Therefore, we propose play role while thioltransferase repair system