[Separation of cholesterol-specific cytochrome P-450 regions and their localization in the polypeptide chain]

The separation of the two domains, disclosed by limited trypsinolysis in the cholesterol side chain cleavage cytochrome P-450, by covalent chromatography on thiopropyl-Sepharose 6B is described. The domains F1 (MW 27 000) and F2 (MW 22 000) are shown to belong to the N-terminal and C-terminal regions of the polypeptide chain respectively.