Thioredoxin peroxidase system in adrenocortical mitochondria

We identified SP-22 that had been found as a substrate protein for mitochondrial ATP-dependent protease to be a thioreoxin peroxidase in adrenocortical mitochondria. It catalyzes thioredoxin dependent reduction of peroxides including hydrogen peroxide. Adrenocortical mitochondria also contain thioredoxin and its reductase different from the cytosolic counterparts. We purified these three mitochondrial proteins and determined nucleotide sequences of their cDNA. These three proteins constructed a new electron transport system in mitochondria to reduce peroxides, protecting mitochondrial components such as enzymes and nucleic acids from damage by reactive oxygen species. Adrenocortical mitochondria contain several hydroxylases for steroids and an electron-donating system for them (adrnodoxin and adrenodoxin reductase). These oxidoredutases along with the mitochondrial respilatory chain vigorously generate reactive oxygen species and the adrenal cortex is known to be active in lipid peroxidation. Therefore, the thioredoxin peroxidase system may play a crucial role in maintaining mitochondrial function.

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本文データは山口大学医学会の許諾に基づきCiNiiから複製したものである