Diacylglycerol lipase and kinase activities in rabbit aorta and coronary microvessels.
Diacylglycerol lipase and kinase activities in rabbit aorta and coronary microvessels.
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兔主动脉和冠状微血管中的二酰基甘油脂肪酶和激酶活性。
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发表时间：
1986
期刊：
影响因子：
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通讯作者：
M. Hee
中科院分区：
文献类型：
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作者：
D. Severson;M. Hee
测量兔主动脉（内膜中层）和冠状微血管的颗粒和可溶性部分中的二酰基甘油脂肪酶和激酶活性。对于兔主动脉，1-棕榈酰-2-油酰-sn-甘油在sn-1位置的水解的最适pH值为5-6，并且大于在sn-2位置的水解（最适pH为6.5）。在 pH 5 和 6.5 的孵育过程中仅积累 2-单酰基甘油。这些结果与有序的两步反应顺序一致，其中 sn-1 位的脂肪酸首先被释放，然后通过具有中性 pH 最佳值的单酰基甘油脂肪酶从 2-单酰基甘油中水解脂肪酸。 pH 6.5 下的脂肪酶活性（sn-2 水解）在所有底物浓度下均大于激酶活性。二酰基甘油的 sn-2 位置上花生四烯酸的存在增加了激酶活性，但对脂肪酶活性几乎没有影响。激酶活性主要是颗粒状的，而二酰基甘油脂肪酶的50-60%和单酰基甘油脂肪酶的50%活性是可溶性的。二酰基甘油脂肪酶和激酶也存在于冠状微血管制剂中。将酶制剂与 cAMP 依赖性蛋白激酶预孵育不会增强冠状微血管中的二酰基甘油脂肪酶（sn-2 水解）活性。
Diacylglycerol lipase and kinase activities were measured in particulate and soluble fractions from rabbit aorta (intima-media) and coronary microvessels. With rabbit aorta, the hydrolysis at the sn-1 position of 1-palmitoyl-2-oleoyl-sn-glycerol had a pH optimum of 5-6 and was greater than hydrolysis at the sn-2 position (pH optimum of 6.5). Only the 2-monoacylglycerol accumulated during incubations at pH 5 and 6.5. These results are consistent with an ordered two-step reaction sequence where the fatty acid at the sn-1 position is released first, followed by the hydrolysis of the fatty acid from the 2-monoacylglycerol by a monoacylglycerol lipase with a neutral pH optimum. Lipase activity (sn-2 hydrolysis) at pH 6.5 was greater than kinase activity at all substrate concentrations. The presence of arachidonate at the sn-2 position of the diacylglycerol increased kinase activity but had little effect on lipase activity. Kinase activity was mainly particulate, whereas 50-60% of diacylglycerol lipase and 50% of monoacylglycerol lipase activity were soluble. Diacylglycerol lipase and kinase were also present in coronary microvessel preparations. Diacylglycerol lipase (sn-2 hydrolysis) activity in coronary microvessels was not enhanced by preincubation of the enzyme preparation with cAMP-dependent protein kinase.