ARACHIDONOYL DIACYLGLYCEROL KINASE

我们以前纯化和表征的花生四烯酸 二酰基甘油激酶，并表明它存在于睾丸中， 大脑和视网膜。 这种酶是至少十种 存在于哺乳动物组织中的二酰基甘油激酶。 我们有 现已部分纯化并表征了另外的二酰基甘油， 激酶，其与花生四烯酸二酰基甘油共表达 激酶。 二酰基甘油激酶是可溶的，但可以结合到 单层脂质囊泡。 两种类型的结合位点似乎 参与其中，一个与囊泡相关的酸性 脂质和一个与囊泡相关的甘油二酯相互作用。 这两种类型的结合位点必须被接合以实现有效的结合。 酶-囊泡相互作用 在这些条件下，当Mg 2 + 和ATP存在于介质中，酶-囊泡相互作用是 最佳的和相关的催化。 即便如此，线性反应速率 是一种复杂的功能，其他人称之为酶的“滑行“， 和“跳跃”现象。 这种酶显然与表面结合 催化一些反应，然后从反应中分离出来 表面，结合到一个新的囊泡，并开始新一轮的催化。 资助NIH拨款RR 00166和霍华德休斯医学研究所。 [This该项目也在神经科学核心部分报道。

We previously purified and characterized an arachidonoyl diacylglycerol kinase and showed that it is present in the testis, brain, and retina of baboons. The enzyme is one of at least ten diacylglycerol kinases that are present in mammalian tissues. We have now partially purified and characterized an additional diacylglycerol kinase, which is coexpressed with the arachidonoyl diacylglycerol kinase. The diacylglycerol kinase is soluble, but can bind to unilamellar lipid vesicles in vitro. Two types of binding sites seem to be involved, one that interacts with vesicle-associated acidic lipids and one that interacts with vesicle-associated diacylglycerol. Both types of binding sites must be engaged for effective enzyme-vesicle interaction. Under these conditions and when both Mg2+ and ATP are present in the medium, enzyme-vesicle interaction is optimal and correlates with catalysis. Even so, linear reaction rates are a complex function of what others have termed enzyme "scooting " and "hopping" phenomena. The enzyme apparently binds to the surface of a vesicle, catalyzes a few reactions, then dissociates from that surface, binds to a new vesicle, and begins a new round of catalysis. FUNDING NIH grant RR00166 and the Howard Hughes Medical Institute. [This project was also reported in the Neuroscience Core section.]