Murphy D J, Mukherjee K D, Woodrow I E
Eur J Biochem. 1984 Mar 1;139(2):373-9. doi: 10.1111/j.1432-1033.1984.tb08016.x.
The biosynthesis of linoleic acid has been investigated, using oleoyl-CoA as a substrate, in microsomal preparations from young leaves of Pisum sativum. Oleoyl moieties from oleoyl-CoA were preferentially acylated to lysophosphatidylcholine by an acyltransferase to produce an oleoylglycerophosphocholine. Kinetic data are presented which argue for a direct desaturation of the oleoyl moieties of this oleoyl glycerophosphocholine to linoleoyl moieties. There was no evidence of a subsequent acyltransfer of linoleoyl moieties either to form thioesters or oxygen esters in other complex lipids. The kinetics were also consistent with a functional coupling of the lysophosphatidylcholine acyltransferase with the oleate desaturase. There was little exchange of the oleoyl glycerophosphocholine from the bulk membrane lipid with that newly synthesised by the lysophosphatidylcholine acyltransferase. Rather, the newly synthesised oleoylglycerophosphocholine seemed to be directly channelled to the vicinity of the desaturase. The results are discussed in the context of 'metabolite channelling'. The consequences for desaturase activity and its regulation are also examined.
利用油酰辅酶A作为底物，对豌豆幼叶微粒体制剂中油酸的生物合成进行了研究。油酰辅酶A中的油酰部分被酰基转移酶优先酰化到溶血磷脂酰胆碱上，生成油酰甘油磷酸胆碱。给出的动力学数据表明，该油酰甘油磷酸胆碱的油酰部分直接去饱和生成亚油酰部分。没有证据表明亚油酰部分随后会酰基转移形成硫酯或在其他复合脂质中形成氧酯。动力学也与溶血磷脂酰胆碱酰基转移酶与油酸去饱和酶的功能偶联一致。由溶血磷脂酰胆碱酰基转移酶新合成的油酰甘油磷酸胆碱与大量膜脂中的油酰甘油磷酸胆碱几乎没有交换。相反，新合成的油酰甘油磷酸胆碱似乎直接被引导到去饱和酶附近。在“代谢物通道化”的背景下对结果进行了讨论。还研究了对去饱和酶活性及其调节的影响。
