Purification and comparative characterization of cytochrome P-450scc (CYP XIA1) from sheep adrenocortical mitochondria.
Cytochrome P-450scc (CYP XI A1) was purified from sheep adrenocortical mitochondria. The purified cytochrome was found to be homogeneous on SDS-polyacrylamide gel electrophoresis and to have a heme content of 20.8 nmol/mg of protein. Its amino acid composition and NH2-terminal amino acid sequence were determined, and compared with those of other known mammalian and fish cytochromes P-450scc. EPR spectra of the cytochrome P-450scc were measured for oxidized and NO-reduced forms in the presence or absence of cholesterol and/or adreno-ferredoxin. Spectral properties of these various forms were very similar to those of the bovine enzyme. Circular dichroism spectra of the purified sheep cytochrome P-450scc in the oxidized and dithionite-reduced forms, and of their complexed forms with cholesterol or adreno-ferredoxin were analyzed in the region from 200 to 700 nm. The difference CD spectrum of the oxidized cytochrome P-450scc complexed with adreno-ferredoxin minus the oxidized form suggests an increase in the high-spin form upon the addition of adreno-ferredoxin. This may suggest a direct influence of the adreno-ferredoxin binding to the heme moiety of the oxidized cytochrome P-450scc.
Miyatake
A
A
Research Equipment Center, Kagawa Medical School, Japan.
Tsubaki
M
M
Hori
H
H
Ichikawa
Y
Y
D000302:Adrenal Cortex / Q000201:enzymology*; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000737:chemistry / Q000302:isolation & purification*; D002942:Circular Dichroism; D004578:Electron Spin Resonance Spectroscopy; D008928:Mitochondria / Q000201:enzymology; D008969:Molecular Sequence Data; D012756:Sheep
D000596:Amino Acids; D002786:Cholesterol Side-Chain Cleavage Enzyme