ARACHIDONOYL DIACYLGLYCEROL KINASE

我们之前提纯并鉴定了一种花生四烯酰基 发现它存在于睾丸中， 脑部和视网膜的变化。这种酶是至少十种酶中的一种 存在于哺乳动物组织中的二酰基甘油激动酶。我们有 现在部分提纯并表征了另一种二酰甘油 与花生四烯酸二酯甘油共表达的激酶 激活剂。甘油二酯激酶是可溶的，但可以结合到 体外培养的单层脂泡。两种类型的结合位点似乎 参与其中，与囊泡相关的酸性物质相互作用 脂类和与囊泡相关的二酰甘油相互作用的一种。 两种类型的结合位点都必须参与才能有效 酶-囊泡相互作用。在这些条件下，当两个镁离子 和ATP存在于介质中，酶-囊泡相互作用是 最佳，并与催化相关。即便如此，线性反应率 是其他人所说的酶的一种复杂的功能 和“跳跃”现象。这种酶显然与表面结合在一起。 小泡，催化几个反应，然后与之解离 表面，结合到一个新的囊泡，并开始新一轮的催化。 资助美国国立卫生研究院拨款RR00166和霍华德·休斯医学研究所。 [《神经科学核心》栏目也报道了这个项目。]

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.]