Fugman D A, Shirai K, Jackson R L, Johnson J D
Biochim Biophys Acta. 1984 Sep 12;795(2):191-5. doi: 10.1016/0005-2760(84)90065-1.
The self-quenching dye, 6-carboxyfluorescein, has been encapsulated into sonicated vesicles of egg phosphatidylcholine. Porcine pancreatic phospholipase A2 and bovine milk lipoprotein lipase catalyze the hydrolysis of the phosphatidylcholine resulting in the release of the encapsulated dye and a large increase in 6-carboxyfluorescein fluorescence. The fluorescence increase occurs in parallel with the formation of lysophosphatidylcholine and is strongly dependent on Ca2+ for phospholipase A2 catalysis and on apolipoprotein C-II for hydrolysis by lipoprotein lipase. Other apolipoproteins, including apolipoproteins C-III, C-I, and A-I, do not enhance lipoprotein lipase activity towards this substrate. We conclude that the enhancement of lipoprotein lipase activity by apolipoprotein C-II is a specific property of the activator protein due to its interaction with lipoprotein lipase or an enzyme/lipid interface and not a characteristic of lipid-binding proteins in general.
自猝灭染料6-羧基荧光素已被包裹在经超声处理的卵磷脂囊泡中。猪胰磷脂酶A2和牛乳脂蛋白脂肪酶催化卵磷脂的水解，导致包裹的染料释放，6-羧基荧光素荧光大幅增加。荧光增加与溶血卵磷脂的形成同时发生，并且强烈依赖于Ca2+进行磷脂酶A2催化，以及依赖于载脂蛋白C-II进行脂蛋白脂肪酶的水解。其他载脂蛋白，包括载脂蛋白C-III、C-I和A-I，不会增强脂蛋白脂肪酶对该底物的活性。我们得出结论，载脂蛋白C-II对脂蛋白脂肪酶活性的增强是激活蛋白的一种特异性特性，这是由于它与脂蛋白脂肪酶或酶/脂质界面相互作用，而不是一般脂质结合蛋白的特征。
