Tang W, Sun G Y
Neurochem Res. 1985 Oct;10(10):1343-53. doi: 10.1007/BF00964977.
Evidence is presented to indicate a metabolic relationship between arachidonic acid activation and its transfer to lysophospholipids by brain microsomes. Thus, in the presence of 1-acylglycerophosphocholines or 1-acyl-glycerophosphoinositols, the activation of labeled arachidonate to its acyl-CoA was enhanced, and the acyl-CoA formed was, in turn, transferred to the lysophospholipids to form the respective diacyl-glycerophospholipids. The "coupling effect" seems to pertain mainly to the lysophospholipids which are good substrates of the acyltransferase. Other lyso-compounds were either not effective or inhibitory to the arachidonate activation process. The activation-transfer activity mediated by the fatty acid ligase and acyltransferase could be dissociated by Triton X-100, which apparently stimulated the acyl-CoA ligase activity but inhibited the acyltransferase. These results suggest that fatty acid ligase and acyltransferase are located in close proximity within the membrane domain. The existence of a close metabolic relationship between these two enzymic reactions is important for maintaining a dynamic equilibrium between the free fatty acids and the membrane phospholipids. The mechanism is also useful in regulating the cellular acyl-CoA and lysophospholipid metabolism, because both compounds have membrane perturbing properties when present in excessive quantity.
有证据表明花生四烯酸的激活与其被脑微粒体转移至溶血磷脂之间存在代谢关系。因此，在1-酰基甘油磷酸胆碱或1-酰基甘油磷酸肌醇存在的情况下，标记的花生四烯酸向其酰基辅酶A的激活增强，并且形成的酰基辅酶A继而被转移至溶血磷脂以形成相应的二酰基甘油磷脂。“偶联效应”似乎主要与作为酰基转移酶良好底物的溶血磷脂有关。其他溶血化合物对花生四烯酸激活过程要么无效，要么具有抑制作用。由脂肪酸连接酶和酰基转移酶介导的激活-转移活性可被 Triton X-100 解离，Triton X-100 显然刺激了酰基辅酶A连接酶活性，但抑制了酰基转移酶。这些结果表明脂肪酸连接酶和酰基转移酶在膜结构域内紧密相邻。这两种酶促反应之间紧密的代谢关系的存在对于维持游离脂肪酸和膜磷脂之间的动态平衡很重要。该机制在调节细胞酰基辅酶A和溶血磷脂代谢方面也很有用，因为这两种化合物在过量存在时都具有膜扰动特性。
