Dommes P, Dommes V, Kunau W H
J Biol Chem. 1983 Sep 25;258(18):10846-52.
Evidence is presented that Candida tropicalis grown on oleic acid as sole carbon and energy source possesses the ability to degrade saturated as well as unsaturated fatty acids. Inducible activities of the four enzymes required for beta-oxidation of saturated fatty acids are demonstrated in this organism. Furthermore, it is shown that 2,3-enoyl-CoA isomerase and 2,4-dienoyl-CoA reductase are induced simultaneously with the other beta-oxidation enzymes. A partial purification of 2,4-dienoyl-CoA reductase is described. This reductase has a specific requirement for NADPH, is unable to utilize NADH, and catalyzes the conversion of 2-trans, 4-cis-decadienoyl-CoA to 3-trans-decenoyl-CoA. It also reduces 2-trans, 4-trans-dienoyl-CoA esters. In vitro studies with extracts from oleate-grown cells of C. tropicalis containing the beta-oxidation enzymes showed that 4-cis-decenoyl-CoA, a metabolite of linoleic acid, was only degraded when the 2,4-dienoyl-CoA reductase step was not blocked by lack of NADPH. Based on the properties of the partially purified 2,4-dienoyl-CoA reductase and the results of the in vitro degradation studies, we conclude that in C. tropicalis the reductase together with the 2,3-dienoyl-CoA isomerase is necessary to link the degradation of unsaturated fatty acids to the beta-oxidation cycle. The implication of this conclusion for degradation of unsaturated fatty acids in general is discussed.
有证据表明，热带假丝酵母在以油酸作为唯一碳源和能源生长时，具有降解饱和脂肪酸以及不饱和脂肪酸的能力。在这种微生物中证明了饱和脂肪酸β-氧化所需的四种酶的可诱导活性。此外，还表明2,3-烯酰辅酶A异构酶和2,4-二烯酰辅酶A还原酶与其他β-氧化酶同时被诱导。描述了2,4-二烯酰辅酶A还原酶的部分纯化。这种还原酶对NADPH有特定需求，不能利用NADH，并催化2-反式，4-顺式-癸二烯酰辅酶A转化为3-反式-癸烯酰辅酶A。它还能还原2-反式，4-反式-二烯酰辅酶A酯。对含有β-氧化酶的热带假丝酵母油酸生长细胞提取物进行的体外研究表明，亚油酸的代谢产物4-顺式-癸烯酰辅酶A只有在2,4-二烯酰辅酶A还原酶步骤不被NADPH缺乏所阻断时才会被降解。基于部分纯化的2,4-二烯酰辅酶A还原酶的特性和体外降解研究的结果，我们得出结论，在热带假丝酵母中，该还原酶与2,3-二烯酰辅酶A异构酶一起是将不饱和脂肪酸降解与β-氧化循环联系起来所必需的。讨论了这一结论对一般不饱和脂肪酸降解的意义。
