Functional Reconstitution of Cytochrome P-450scc with Hemin Activated with Woodward's Reagent K

was used to obtain the apoprotein. Functional reconstitution of the hemin derivative with apocytochrome P-450,, was achieved. The reconstituted hemeprotein was purified, and the resulting preparation contained no P-420 form and had the same cholesterol-hydroxylating activity as a control preparation. 30% of the reconstituted hemin was covalently bound to protein. Heme-linked peptide (Gly7-Phe'e4) was isolated. Its possible role in the active site formation of cytochrome P-450,, is dis- cussed.