DEHYDROXYLATION OF CHOLIC-ACID AT C-12 AND EPIMERIZATION AT C-5 AND C-7 BY BACTEROIDES SPECIES
DEHYDROXYLATION OF CHOLIC-ACID AT C-12 AND EPIMERIZATION AT C-5 AND C-7 BY BACTEROIDES SPECIES
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DOI：
10.1016/0022-4731(84)90304-2
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发表时间：
1984-01-01
影响因子：
4.1
通讯作者：
EDENHARDER, R
中科院分区：
文献类型：
--
作者：
EDENHARDER, R
对2060株新鲜分离的人肠道优势植物群细菌培养物（其中包括1029株糖分解类杆菌）进行胆酸转化试验。八个拟杆菌菌株减少胆酸盐鹅脱氧胆酸盐，而73株脱羟基在C7，产生脱氧胆酸盐。在许多菌株中观察到羟基（主要在C7）的同时氧化。没有菌株能够同时在C7和C12处同时脱羟基。1株分离株，鉴定为B的混合培养物。fragilis和B. iniformis，在C5差向异构化胆酸，同时在C7差向异构化、氧化和脱羟基化。鉴定了以下转化产物：3 α，7. α，12. alpha.-三羟基-5 α-胆烷酸，3 α，7 β，12. alpha.-三羟基-5 β-胆烷酸（熊胆酸），3 α，12. alpha.-二羟基-7-酮-5 β-胆烷酸，3 α，12. alpha.-二羟基-5 α-胆烷酸和3 α，12. alpha.-二羟基-5 α-胆烯酸当新鲜分离物首先进行胆酸盐转化测试时，检测到脱羟基和差向异构化能力。经过几次连续的转移，他们已经认不出来了。混合粪便培养物不能证明胆酸盐在C12的脱羟基作用。然而，可能的中间体3 α，7.阿尔法。二羟基-5 β- chol-11-enoate被粪便悬浮液大量氢化。
Freshly isolated cultures (2060) of human intestinal bacteria of the predominant flora, among them 1029 strains of saccharolytic Bacteroides species, were tested for cholic acid transformation. Eight Bacteroides strains reduced cholate to chenodeoxycholate, while 73 strains dehydroxylated at C7, producing deoxycholate. Concurrent oxidation of hydroxyl groups, mainly at C7, was seen with many strains. No strain was able to dehydroxylate simultaneously simultaneously at C7 and C12. One isolate, identified as a mixed culture of B. fragilis and B. iniformis, epimerized cholic acid at C5 and simultaneously epimerized, oxidized and dehydroxylated at C7. The following transformation products were identified; 3.alpha.,7.alpha.,12.alpha.-trihydroxy-5.alpha.-cholanoic acid, 3.alpha.,7.beta.,12.alpha.-trihydroxy-5.beta.-cholanoic acid (ursocholic acid), 3.alpha., 12.alpha.-dihydroxy-7-keto-5.beta.-cholanoic acid, 3.alpha.,12.alpha.-dihydroxy-5.alpha.-cholanoic acid and a 3.alpha.,12.alpha.-dihydroxy-5.alpha.-cholenoic acid. Dehydroxylating and epimerizing abilities were detected when fresh isolates were tested first for cholate transformation. They were no longer recognizable after some serial transfers. Dehydroxylation at C12 of cholate could not be demonstrated with mixed fecal cultures. The possible intermediate, however, 3.alpha.,7.alpha.-dihydroxy-5.beta.-chol-11-enoate, was abundantly hydrogenated by stool suspensions.