Kreit Joseph
FEMS Microbiol Lett. 2017 Feb 1;364(3). doi: 10.1093/femsle/fnx007.
An overview on the microbial sterol catabolism is described with a focus on the catabolic step of the 3β-hydroxy-5-en structure. Cholesterol oxidase transforms this structure into the corresponding 3-keto-4-en feature, and thus initiates the sterol molecule catabolism. The oxidase has been found in a large number of microorganisms, especially in Actinobacteria as species of Rhodococcus and Streptomyces. Other Actinobacteria as species of Mycobacterium and Nocardia possess NAD(P)-dependent dehydrogenase for this catabolic step. In Rhodococcus jostii, oxidation of the C26 of the sterol side chain is the initiating step. The resulting stenone or sterol-C26-oic acid is then catabolized according to two subpathways: cleavage of the sterol side chain and degradation of the steroid nucleus. Divergent items concerned with the enzymes that transform the sterol 3β-hydroxy-5-en are discussed.
本文对微生物甾醇分解代谢进行了概述，重点关注3β-羟基-5-烯结构的分解代谢步骤。胆固醇氧化酶将该结构转化为相应的3-酮-4-烯特征，从而启动甾醇分子的分解代谢。已在大量微生物中发现这种氧化酶，尤其是在红球菌属和链霉菌属等放线菌中。其他放线菌，如分枝杆菌属和诺卡氏菌属的物种，在这一分解代谢步骤中具有NAD(P)依赖性脱氢酶。在约氏红球菌中，甾醇侧链C26的氧化是起始步骤。生成的甾烯酮或甾醇-C26-油酸随后根据两条子途径进行分解代谢：甾醇侧链的裂解和甾体核的降解。文中讨论了与转化甾醇3β-羟基-5-烯的酶相关的不同事项。
