Farese R V, Prudente W J
Biochim Biophys Acta. 1977 Feb 28;496(2):567-70. doi: 10.1016/0304-4165(77)90339-7.
Following simple homogenization, significant amounts of mitochondrial-derived, cholesterol side chain cleaving enzyme (desmolase) activity are recovered in rat adrenal 105 000 X g-supernatant fraction. Corticotropin administration enhances soluble desmolase activity, and cycloheximide potentiates this effect. The lipid droplet fraction which has no desmolase activity markedly enhances pregnenolone synthesis in the soluble desmolase preparations, presumably by supplying free cholesterol substrate. Corticotropin particularly with cycloheximide pretreatment, enhances lipid fraction activity. Thus increased cholesterol availability may largely explain the corticotropin effect on the soluble desmolase system. Since protein synthesis is required for corticotropin activity in intact mitochondria, but not in calcium-swollen mitochondria or the soluble enzyme system, the labile protein apparently required during corticotropin action may function to overcome a "barrier" which exists only in the intact mitochondria and restrains cholesterol side chain cleavage.
经过简单的匀浆处理后，在大鼠肾上腺105 000×g上清液组分中可回收大量线粒体来源的胆固醇侧链裂解酶（脱氨酶）活性。促肾上腺皮质激素的施用可增强可溶性脱氨酶活性，而环己酰亚胺可增强这种作用。没有脱氨酶活性的脂滴组分在可溶性脱氨酶制剂中显著增强孕烯醇酮的合成，大概是通过提供游离胆固醇底物来实现的。促肾上腺皮质激素，特别是经过环己酰亚胺预处理后，可增强脂滴组分的活性。因此，胆固醇可用性的增加可能在很大程度上解释了促肾上腺皮质激素对可溶性脱氨酶系统的作用。由于完整线粒体中促肾上腺皮质激素的活性需要蛋白质合成，但在钙肿胀的线粒体或可溶性酶系统中则不需要，因此促肾上腺皮质激素作用期间显然需要的不稳定蛋白质可能起到克服仅存在于完整线粒体中并抑制胆固醇侧链裂解的“屏障”的作用。
