Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford OX3 7LE, UK.
Prog Lipid Res. 2013 Jan;52(1):15-42. doi: 10.1016/j.plipres.2012.08.002. Epub 2012 Sep 21.
Different lipid fractions in humans have characteristic fatty acid profiles and these are maintained partly through diet and to a lesser extent through endogenous synthesis. The enzyme stearoyl-CoA desaturase (SCD; EC 1.14.99.5) is the rate-limiting enzyme in the synthesis of monounsaturated fatty acids such as palmitoleic acid (16:1 n-7) and oleic acid (18:1 n-9). These are the two most abundant monounsaturated fatty acids in human plasma lipids, membranes and adipose tissue. Although in quantitative terms, the endogenous synthesis of fatty acids in humans is not great in most circumstances, it is becoming increasingly evident that SCD plays important structural and metabolic roles. In addition, 16:1 n-7 has been purported to act as a beneficial 'lipokine' in an animal model. Research in humans has relied on indirect measurements of SCD1 activity and therefore, much of our understanding has come from work on animal models. However, results have been somewhat counterintuitive and confusing, so the purpose of this review is to try to summarise our current understanding of this fascinating enzyme.
人体内不同的脂质成分具有特定的脂肪酸谱，这些脂肪酸谱部分通过饮食维持，而在较小程度上则通过内源性合成来维持。硬脂酰辅酶 A 去饱和酶（SCD；EC 1.14.99.5）是合成单不饱和脂肪酸如棕榈油酸（16:1 n-7）和油酸（18:1 n-9）的限速酶。这两种单不饱和脂肪酸是人体血浆脂质、膜和脂肪组织中最丰富的两种。尽管从定量的角度来看，在大多数情况下，人类自身的脂肪酸内源性合成量并不多，但越来越明显的是，SCD 发挥着重要的结构和代谢作用。此外，16:1 n-7 据称在动物模型中作为有益的“脂联素”发挥作用。人类的研究依赖于 SCD1 活性的间接测量，因此，我们的大部分认识都来自于对动物模型的研究。然而，结果有些违背直觉且令人困惑，因此，本篇综述的目的是试图总结我们目前对这种迷人酶的理解。
