TY - JOUR
T1 - Effects of adrenal steroid activator protein on the conversion of various 20- and 22-hydroxycholesterols to pregnenolone by adrenal mitochondrial enzymes
AU - Teicher, Beverly A.
AU - Shikita, Mikio
AU - Talalay, Paul
N1 - Funding Information:
These studies were supported by Grant AM-07422 from the National Institutes of Health and by a grant from the Ministry of Education of Japan. We wish to express our appreciation to our colleague Dr. Masato Koreeda for his valuable advice and gift the compounds studied.
PY - 1978/8/29
Y1 - 1978/8/29
N2 - A heat-stable protein activator from bovine adrenal cortex mitochondria stimulates the conversion of cholesterol to pregnenolone in crude extracts of adrenal mitochondria, and resembles in some of its properties, the sterol carrier protein of liver (Kan et al. Biochem. Biophys. Res. Commun. 48, 423-429, 1972). We have shown that activator preparations also stimulate highly purified adrenal enzyme preparations comprising four components: cytochrome P-450 specific for side chain cleavage, adrenodoxin, adrenodoxin reductase, and an NADPH-generating system. Furthermore, this activator stimulates the conversion not only of cholesterol, but also of (20S)-20-hydroxycholesterol, (22R)-22-hydroxycholesterol, and (20R, 22R)-20,22-dihydroxycholesterol to pregnenolone. Our findings provide additional evidence that the steroid-activator complexes are the substrates for the side chain cleavage enzyme and that the monohydroxy and dihydroxycholesterols are true intermediates in the conversion of cholesterol to pregnenolone by bovine adrenal cortex mitochondria.
AB - A heat-stable protein activator from bovine adrenal cortex mitochondria stimulates the conversion of cholesterol to pregnenolone in crude extracts of adrenal mitochondria, and resembles in some of its properties, the sterol carrier protein of liver (Kan et al. Biochem. Biophys. Res. Commun. 48, 423-429, 1972). We have shown that activator preparations also stimulate highly purified adrenal enzyme preparations comprising four components: cytochrome P-450 specific for side chain cleavage, adrenodoxin, adrenodoxin reductase, and an NADPH-generating system. Furthermore, this activator stimulates the conversion not only of cholesterol, but also of (20S)-20-hydroxycholesterol, (22R)-22-hydroxycholesterol, and (20R, 22R)-20,22-dihydroxycholesterol to pregnenolone. Our findings provide additional evidence that the steroid-activator complexes are the substrates for the side chain cleavage enzyme and that the monohydroxy and dihydroxycholesterols are true intermediates in the conversion of cholesterol to pregnenolone by bovine adrenal cortex mitochondria.
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U2 - 10.1016/0006-291X(78)91381-5
DO - 10.1016/0006-291X(78)91381-5
M3 - Article
C2 - 697872
AN - SCOPUS:0018142932
SN - 0006-291X
VL - 83
SP - 1436
EP - 1441
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
IS - 4
ER -