Pichard A L, Cheung W Y
J Biol Chem. 1977 Jul 25;252(14):4872-5.
Brain cytoplasmic cyclic 3':5'-nucleotide phosphodiesterase (EC 3.1.4.17) requires an endogenous Ca2+-binding protein for ful activity. We now show that lysophosphatidylcholine also effectively enhances activator-deficient phosphodiesterase activity. Stimulation by both ligands was immediate and reversible; both rendered the enzyme more thermally labile, decreased the energy of activation, and increased the Vmax of phosphodiesterase without affecting its apparent Km for adenosine 3'5'-monophosphate. However, the cofactor requirements of the two ligands were different. Although the protein activator gave a greater stimulation than lysophosphatidylcholine, the simultaneous presence of the two gave a stimulation comparable to lysophosphatidylcholine, suggesting that the effect of the latter was predominant. Phosphodiesterase was also stimulated by oleic acid, cardiolipin, and phosphatidylinositol, albeit to a less extent.
脑细胞质环3',5'-核苷酸磷酸二酯酶（EC 3.1.4.17）的充分活性需要一种内源性钙结合蛋白。我们现在表明，溶血磷脂酰胆碱也能有效地增强缺乏激活剂的磷酸二酯酶活性。两种配体的刺激都是即时且可逆的；两者都使该酶对热更不稳定，降低了激活能，并增加了磷酸二酯酶的Vmax，而不影响其对3',5'-环磷酸腺苷的表观Km。然而，两种配体的辅因子需求不同。尽管蛋白质激活剂比溶血磷脂酰胆碱产生更大的刺激，但两者同时存在时产生的刺激与溶血磷脂酰胆碱相当，这表明后者的作用占主导。磷酸二酯酶也受到油酸、心磷脂和磷脂酰肌醇的刺激，尽管程度较小。
