磷脂酶A2对纯化胃小泡的作用。

Effect of phospholipase A2 on purified gastric vesicles.

作者信息

Saccomani G, Chang H H, Spisni A, Helander H F, Spitzer H L, Sachs G

出版信息

J Supramol Struct. 1979;11(4):429-44. doi: 10.1002/jss.400110402.

Abstract

The phospholipid and fatty acid composition and role of phospholipids in enzyme and transport function of gastric (H+ + K+)-ATPase vesicles was studied using phospholipase A2 (bee venom). The composition (%) was phosphatidyl-choline (PC) 33%; sphingomyelin (sph) 25%; phosphatidylethanolamine (PE) 22%; phosphatidylserine (PS) 11%; and phosphatidylinositol (PI) 8%. The fatty acid composition showed a high degree of unsaturation. In both fresh and lyophilized preparations, even with prolonged incubation, only 50% of phospholipids were hydrolyzed, but the amount of PE and PS disappearing was increased following lyophilization. There was a marked decrease in K+-ATPase activity (75%) but essentially no loss of the associated K+ p-nitrophenyl phosphatase was found. ATPase activity could be largely restored by various phospholipids (PE greater than PC greater than PS). There was also an increase in Mg2+-ATPase activity, partially reversed in fresh preparations by the addition of phospholipids (PE greater than PS greater than PC). Proton transport activity of the preparation was rapidly inhibited, initially due to a large increase in the HCl permeability of the preparation. Associated with these enzymatic and functional changes, the ATP-induced conformational changes, as indicated by circular dichroism spectra were inhibited.

摘要

利用磷脂酶A2（蜂毒）研究了胃（H⁺+K⁺）-ATP酶囊泡的磷脂和脂肪酸组成以及磷脂在酶和转运功能中的作用。其组成（%）为：磷脂酰胆碱（PC）33%；鞘磷脂（sph）25%；磷脂酰乙醇胺（PE）22%；磷脂酰丝氨酸（PS）11%；磷脂酰肌醇（PI）8%。脂肪酸组成显示出高度不饱和。在新鲜制剂和冻干制剂中，即使长时间孵育，也只有50%的磷脂被水解，但冻干后PE和PS消失的量增加。K⁺-ATP酶活性显著降低（75%），但未发现相关的K⁺对硝基苯磷酸酶有实质性损失。各种磷脂（PE＞PC＞PS）可在很大程度上恢复ATP酶活性。Mg²⁺-ATP酶活性也有所增加，在新鲜制剂中通过添加磷脂（PE＞PS＞PC）可部分逆转。制剂的质子转运活性迅速受到抑制，最初是由于制剂的HCl通透性大幅增加。与这些酶促和功能变化相关，圆二色光谱显示的ATP诱导的构象变化受到抑制。