Abstract
For some time it has been known that the side chain of cholesterol sulfate is cleaved by the cleavage enzyme system present in bovine adrenal mitochondria without prior hydrolysis of the sulfate moiety. In this work, other inorganic esters as well as some organic esters of cholesterol were tested as substrates for this enzyme system. The results revealed that cholesterol nitrate, cholesterol phosphate, and a series of acyl esters of cholesterol can also be cleaved by the enzyme system to their respective pregnenolone derivatives without first being hydrolyzed to cholesterol. The rate of oxidation of the carboxylic acid esters decreased as the size of the acyl groups increased. Cholesterol stearate and cholesterol phosphate were demonstrated to be inhibitors of the side chain cleavage of cholesterol. While digitonin, as might be expected, inhibits the cleavage of cholesterol, it accelerates the oxidation of both cholesterol sulfate and cholesterol nitrate. The results reported in this paper add support to the previously proposed hypothesis that more than one cholesterol side chain cleavage enzyme system exists in adrenal mitochondria.
Highlights
From the Departments Human Reproduction, Adele Wolfson, Richard Hochberg,g and Seymour Lieberman of Biochemistry and of Obstetrics and Gynecology, and The International
The results reported in this paper add support to the previously proposed hypothesis that more than one cholesterol side chain cleavage enzyme system exists in adrenal mitochondria
Each of the two solutions was divided in half, and each half was incubated with 0.1 ml (800 pg of protein) or 0.15 ml (1200 pg of protein) of bovine adrenal mitochondrial acetone powder suspension, 130,000 cpm of “Hz0, 0.2 ml of NADPH-generating system, and 0.1 M phosphate buffer
Summary
From the Departments Human Reproduction, Adele Wolfson, Richard Hochberg,g and Seymour Lieberman of Biochemistry and of Obstetrics and Gynecology, and The International. The results reported in this paper add support to the previously proposed hypothesis that more than one cholesterol side chain cleavage enzyme system exists in adrenal mitochondria. The enzyme system responsible for the formation of the CZ1intermediate, pregnenolone, by the oxidative cleavage of cholesterol, is the cholesterol side chain cleavage enzyme, a complex multienzyme system thought to be the site of stimulation by ACTH (l-3). It has been previously demonstrated [4,5,6], that a naturally. The costs of publication of this article were defrayed in part by the payment of page charges
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