Domain structure of adrenocortical cytochrome P-450scc: localization of functionally important sites in the polypeptide chain.

Cytochrome P-450scc consists of two domains linked with a short loop of the polypeptide chain; under its hydrolysis with trypsin the domains retain their associated state due to rigid noncovalent interactions. The structural characteristics of the individual domains have been investigated. It is established that domain I containing the haem and the adrenodoxin-binding site is the N-terminal, and domain II the C-terminal moiety of the polypeptide chain of cytochrome P-450scc.