[Localization of tetranitromethane-modified tyrosine residues in domains of cholesterol-hydroxylating cytochrome P-450].

As a continuation of earlier structure-function studies on cholesterol-hydroxylating cytochrome P-450 from the adrenal cortex mitochondria, the present study is concerned with the distribution of tetranitromethane-modified tyrosine residues in the hemo-protein domains. With the aid of thiol-disulfide exchange chromatography and SDS polyacrylamide gel electrophoresis the F1 and F2 fragments of the modified cytochrome P-450 were isolated. Nitrated tyrosine residues were found in the F1 fragment, a heme-containing catalytic domain of the molecule.