Comparative study of cytochrome P-450 in liver microsomes. A form of monkey cytochrome P-450, P-450-MK1, immunochemically cross-reactive with antibodies to rat P-450-male.
Cytochrome P-450, designated as P-450-MK1, which is cross-reactive with antibodies to rat P-450-male, was purified to an electrophoretical homogeneity from liver microsomes of the untreated male crab-eating monkey. The molecular weight of P-450-MK1 was estimated to be 50,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The oxidized form of P-450-MK1 showed a peak at 418 nm, indicating that this cytochrome is in a low spin state. The carbon monoxide-bound reduced form showed a peak at 451 nm. The first 22 amino acid residues of the NH2-terminal sequence of P-450-MK1 was fairly homologous to those of P-450-male (75% identity, not including unidentified amino acid residues). Unlike the P-450-male, P-450-MK1 did not exhibit catalytic activities for testosterone 2 alpha- and 16 alpha-hydroxylations and catalyzed testosterone 6 beta-hydroxylation. It is, therefore, suggested that although the spectral and immunochemical properties and the N-terminal amino acid sequence of P-450-MK1 were similar to those of P-450-male, the physiological functions of P-450-MK1 may be somewhat different from those of P-450-male. Comparison of the physico-chemical properties of P-450-MK1 with those of P-450-D1 and P-450-HM2, which are cross-reactive with anti-P-450-male antibodies, purified from liver microsomes of dogs and humans, respectively, are also discussed.
Ohi
H
H
Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan.
Toratani
S
S
Komori
M
M
Miura
T
T
Kitada
M
M
Kamataki
T
T
D000595:Amino Acid Sequence; D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases; D003429:Cross Reactions; D003577:Cytochrome P-450 Enzyme System / Q000276:immunology* / Q000302:isolation & purification; D004591:Electrophoresis, Polyacrylamide Gel; D000882:Haplorhini; D008252:Macaca fascicularis; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology*; D008969:Molecular Sequence Data; D011374:Progesterone / Q000378:metabolism; D051381:Rats; D013250:Steroid Hydroxylases / Q000378:metabolism
D011374:Progesterone; D003577:Cytochrome P-450 Enzyme System; D013250:Steroid Hydroxylases; D001189:Aryl Hydrocarbon Hydroxylases; C022724:testosterone 7-alpha-hydroxylase, hamster