ENZYMATIC SYNTHESIS OF MONOUNSATURATED FATTY ACIDS
ENZYMATIC SYNTHESIS OF MONOUNSATURATED FATTY ACIDS
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DOI：
10.1021/ar50019a001
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发表时间：
1969-01-01
影响因子：
18.3
通讯作者：
BLOCH, K
中科院分区：
文献类型：
--
作者：
BLOCH, K
现代生物化学研究的一个引人注目的发现是代谢过程，特别是生物合成过程的统一。我们的意思是，绝大多数途径在化学上是独一无二的，而且它们对所有形式的UFE都是通用的。然而，在少数情况下，已知相同的分子具有双重来源。对于氨基酸赖氨酸、烟酸和长链单不饱和脂肪酸的生物合成，已经描述了两条完全不同的化学途径。多种或交替的生物合成途径可能是进化的结果，可以如此合理化。例如，单不饱和脂肪酸生物合成的两条途径的存在被认为意味着其中一条比另一条更原始。当UFe是原始的，UFe过程完全是厌氧的时候，不饱和脂肪酸只能通过厌氧反应形成。随着大气氧气和有氧代谢的出现，新的生物合成反应应运而生。因此，好氧脱饱和度取代了厌氧烯烃的形成过程。正如这一解释所表明的，单烯脂肪酸的氧依赖和氧非依赖的生物合成是截然不同的、完全不相关的化学过程。
One of the striking disclosures of modern biochemical research is the unity of metabolic and especially biosynthetic processes. By this we mean that the vast majority of pathways are chemically unique and, moreover, that they are universal for all forms of Ufe. However, in a few instances identical molecules are known to be of dual origin. Two pathways, totally different chemically, have been described for the bio-synthesis of the amino acid lysine, for nicotinic acid, and for long-chain monounsaturated fatty acids. Multiple or alternate biosynthetic pathways are prob-ably a consequence of evolution and can be so rational-ized. For example, the existence of dual pathways for thebiosynthesis of monounsaturated fatty acids is taken to mean that one is more primitive than the other. When Ufe was primitive and the Ufe processes were entirely anaerobic, unsaturated fatty acids could only be formed by anaerobic reactions. With the advent of atmospheric oxygen and aerobic metabolism, novel biosynthetic reactions evolved. 1 Thus, aerobic desaturation superseded the process of anaerobic olefin formation. As this Account wiU show, the oxy-gen-dependent and the oxygen-independent biosyn-theses of monoolefinic fatty acids are distinct and totally unrelated chemical processes.