GDE4 and GDE7 are membrane-bound enzymes that exhibit lysophospholipase D activities. We found that GDE7 produced not only lysophosphatidic acid (LPA) but also cyclic phosphatidic acid (cPA) from lysophospholipids by a transphosphatidylation reaction. In contrast, GDE4 produced only LPA. The analysis of substrate specificity showed that 1-alkyl-lysophosphospholipids were preferred substrates for both enzymes rather than 1-alkyl-lysophospholipids and 1-alkenyl-lysophospholipids. Among the various lysophospholipids with different polar head groups that were tested, lysophosphatidylglycerol and lysophosphatidylserine were preferred substrates for GDE4 and GDE7, respectively. The detailed analysis of the dependency of the enzyme activities of GDE4 and GDE7 on divalent cations suggested multiple divalent cations were bound in the active sites of both enzymes. Taken together, these results suggest the possibility that GDE7 functions as a cPA-producing enzyme in the body.

中文翻译：

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重组鼠 GDE4 和 GDE7 的表征，产生溶血磷脂酸和/或环状磷脂酸的酶

GDE4 和 GDE7 是表现出溶血磷脂酶 D 活性的膜结合酶。我们发现 GDE7 不仅通过转磷脂酰化反应从溶血磷脂中产生溶血磷脂酸 (LPA)，而且还产生环状磷脂酸 (cPA)。相比之下，GDE4 只产生 LPA。底物特异性分析表明，1-烷基溶血磷脂是两种酶的首选底物，而不是 1-烷基溶血磷脂和 1-烯基溶血磷脂。在测试的具有不同极性头基的各种溶血磷脂中，溶血磷脂酰甘油和溶血磷脂酰丝氨酸分别是 GDE4 和 GDE7 的优选底物。对 GDE4 和 GDE7 的酶活性对二价阳离子的依赖性的详细分析表明，多种二价阳离子结合在两种酶的活性位点上。总之，这些结果表明 GDE7 可能在体内作为一种产生 cPA 的酶发挥作用。