NADPH-dependent beta-oxidation of unsaturated fatty acids with double bonds extending from odd-numbered carbon atoms.
NADPH-dependent beta-oxidation of unsaturated fatty acids with double bonds extending from odd-numbered carbon atoms.
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DOI：
10.1073/pnas.89.15.6673
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发表时间：
1992-08
影响因子：
11.1
通讯作者：
T. E. Smeland;M. Nada;D. Cuebas;H. Schulz
中科院分区：
文献类型：
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作者：
T. E. Smeland;M. Nada;D. Cuebas;H. Schulz
用线粒体提取物和纯化的β-氧化酶研究了5-烯酰辅酶A的线粒体代谢，5-烯酰辅酶A是在具有从奇数碳原子延伸的双键的不饱和脂肪酸的β-氧化过程中形成的。代谢物通过化学计量法和高效液相色谱法鉴定。5-顺式-辛烯酰-CoA（亚麻酸的推定代谢物）被中链酰基-CoA脱氢酶（EC 1.3.99.3）有效地脱氢为2-反式-5-顺式-辛二烯酰-CoA，其被线粒体δ 3，δ 2-烯酰-CoA异构酶（EC www.example.com）或过氧化物酶体三功能酶异构化为3，5-辛二烯酰-CoA。5.3.3.8在大鼠肝脏或大鼠心脏线粒体的可溶性提取物存在下，观察到3，5-辛二烯酰-CoA进一步异构化为2-反式-4-反式-辛二烯酰-CoA，并归因于Δ 3，5，Δ 2，4-二烯酰-CoA异构酶。用通过5-反式-辛烯酰基-CoA脱氢形成的2-反式-5-反式-辛二烯酰基-CoA获得了定性相似的结果。2-反式-4-反式-辛二烯酰基-CoA是NADPH依赖性2，4-二烯酰基-CoA还原酶的底物（EC 1.3.1.34）。大鼠肝线粒体的可溶性提取物催化2-反式-5-顺式-辛二烯酰基-CoA异构化为2-反式-4-反式-辛二烯酰基-CoA，其在添加NADPH、NAD+和CoA后被链缩短为己酰基-CoA、丁酰基-CoA和乙酰基-CoA。因此，我们得出结论，奇数双键，如偶数双键，可以在多不饱和脂肪酸的β-氧化过程中被还原除去。
The mitochondrial metabolism of 5-enoyl-CoAs, which are formed during the beta-oxidation of unsaturated fatty acids with double bonds extending from odd-numbered carbon atoms, was studied with mitochondrial extracts and purified enzymes of beta-oxidation. Metabolites were identified spectrophotometrically and by high performance liquid chromatography. 5-cis-Octenoyl-CoA, a putative metabolite of linolenic acid, was efficiently dehydrogenated by medium-chain acyl-CoA dehydrogenase (EC 1.3.99.3) to 2-trans-5-cis-octadienoyl-CoA, which was isomerized to 3,5-octadienoyl-CoA either by mitochondrial delta 3,delta 2-enoyl-CoA isomerase (EC 5.3.3.8) or by peroxisomal trifunctional enzyme. Further isomerization of 3,5-octadienoyl-CoA to 2-trans-4-trans-octadienoyl-CoA in the presence of soluble extracts of either rat liver or rat heart mitochondria was observed and attributed to a delta 3,5,delta 2,4-dienoyl-CoA isomerase. Qualitatively similar results were obtained with 2-trans-5-trans-octadienoyl-CoA formed by dehydrogenation of 5-trans-octenoyl-CoA. 2-trans-4-trans-Octadienoyl-CoA was a substrate for NADPH-dependent 2,4-dienoyl-CoA reductase (EC 1.3.1.34). A soluble extract of rat liver mitochondria catalyzed the isomerization of 2-trans-5-cis-octadienoyl-CoA to 2-trans-4-trans-octadienoyl-CoA, which upon addition of NADPH, NAD+, and CoA was chain-shortened to hexanoyl-CoA, butyryl-CoA, and acetyl-CoA. Thus we conclude that odd-numbered double bonds, like even-numbered double bonds, can be reductively removed during the beta-oxidation of polyunsaturated fatty acids.