Acetyl-CoA-dependent elongation of fatty acids in Mycobacterium smegmatis.
Acetyl-CoA-dependent elongation of fatty acids in Mycobacterium smegmatis.
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耻垢分枝杆菌中乙酰辅酶A依赖性脂肪酸延伸。
DOI：
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发表时间：
1977
期刊：
影响因子：
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通讯作者：
T. Kusaka
中科院分区：
文献类型：
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作者：
T. Shimakata;Y. Fujita;T. Kusaka
通过硫酸铵分级分离，从从头脂肪酸合成酶中获得了一个耻垢分枝杆菌催化乙酰辅酶A延长中链脂肪酸的酶系统。通过凝胶过滤和DEAE-纤维素色谱将系统分解成三个部分，所有这些部分都是重建延伸活性所需的。这三个级分是高度纯化的烯酰辅酶A水合酶、高度纯化的3-羟酰辅酶A脱氢酶和含有烯酰辅酶A还原酶和硫解酶的级分。重组系统是亲和素不敏感的，需要NADH作为唯一的氢供体，并对pCMB敏感，但不对N-乙基马来酰亚胺或单碘乙酸。癸酰辅酶A和辛酰辅酶A是延伸体系的最佳引物。当癸酰-CoA用作引物时，发现主要产物是月桂酰衍生物（可能是月桂酰-CoA）。获得的证据表明，酰基辅酶A脱氢酶，催化β-氧化的第一步，在延伸系统中没有功能。
An enzyme system of Mycobacterium smegmatis catalyzing the elongation of medium-chain fatty acids with acetyl-CoA was obtained free from de novo fatty acid synthetase by ammonium sulfate fractionation. The system was resolved by gel filtration and DEAE-cellulose chromatography into three fractions, all of which were required for reconstitution of the elongation activity. The three fractions were highly purified enoyl-CoA hydratase, highly purified 3-hydroxyacyl-CoA dehydrogenase, and a fraction containing both enoyl-CoA reductase and thiolase. The reconstituted system was avidin-insenstive, required NADH as a sole hydrogen donor, and was sensitive to pCMB, but not to N-ethylmaleimide or monoiodoacetate. Decanoyl-CoA and octanoyl-CoA were the best primers for the elongation system. When decanoyl-CoA was used as the primer, the major product was found to be a lauroyl derivative (probably lauroyl-CoA). Evidence was obtained suggesting that acyl-CoA dehydrogenase, catalyzing the first step of beta-oxidation, was not functional in the elongation system.