ATP-dependent protease in human placenta

We have found that human placental mitochondria contain ATP-dependent protease in a soluble form. The molecular weight of the protease have been up to 108,000, which is the same as ATP-dependent protease in bovine adrenal cortex. Since this protease has been distributed among steroid hormone-producing tissues such as testis and adrenal cortex and ATP-dependent protease can degrade cytochrome P-450scc, a key enzyme in steroid hormone biosynthesis, we suggest that the protease may have an important role in the regulation of steroid hormone metabolism.