The relation between two molecular species of P-450 in adult testis and 17 alpha-hydroxylase and 17,20-lyase activities.
Two P-450s from adult pig testis were purified to specific contents of 11.2 and 12.0 nmol P-450/mg protein and shown to have minimum molecular weights of 45,000 and 46,000, respectively. The absorption spectra were typical of P-450s. The P-450s were separated from the two fractions by CM-C50 Sephadex column chromatography. One P-450 (M(r) = 45000) exhibited 17,20-lyase activity of 6.78 nmol of androstenedione/min/nmol P-450, on incubation with 17 alpha-hydroxyprogesterone as a substrate. The other P-450 (M(r) = 46,000) exhibited no 17,20-lyase activity. Both P-450s exhibited 17 alpha-hydroxylase activity that amounted to 10 nmol of steroid products. Accordingly, the two molecular species of P-450 are thus markedly different in 17,20-lyase activity toward 17 alpha-hydroxyprogesterone.
Kuwada
M
M
Department of Biochemistry, School of Medicine, Kitasato University, Kanagawa, Japan.
Takizawa
N
N
Sone
Y
Y
D000446:Aldehyde-Lyases / Q000302:isolation & purification / Q000378:metabolism*; D000735:Androstenedione / Q000378:metabolism; D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000302:isolation & purification / Q000378:metabolism*; D008297:Male; D008861:Microsomes / Q000201:enzymology; D011374:Progesterone / Q000378:metabolism; D013254:Steroid 17-alpha-Hydroxylase / Q000302:isolation & purification / Q000378:metabolism*; D013379:Substrate Specificity; D013552:Swine; D013737:Testis / Q000201:enzymology*
D000735:Androstenedione; D011374:Progesterone; D003577:Cytochrome P-450 Enzyme System; D013254:Steroid 17-alpha-Hydroxylase; C022445:progesterone 17-alpha-hydroxylase; D000446:Aldehyde-Lyases