Inhibition of (Na,K)ATPase by the extract from Artemia salina

对卤虫（Artemia salinahas）胚胎发育过程中（Na，K）ATPase亚基含量的测定表明，在卤虫胚胎发育的早期，α和β亚基均存在。然而，在这些阶段的卤虫没有显示出任何可检测的（Na，K）ATP酶活性，表明（Na，K）ATP酶抑制剂的存在下，在发展卤虫。本研究从卤虫中分离得到了内源性抑制剂，并对其进行了如下表征：1.用胰蛋白酶或木瓜蛋白酶消化抑制剂对其抑制活性没有任何显着影响。热处理对抑制活性没有影响.用有机溶剂提取的抑制剂在TLC板上产生两个活性点，均含有长链脂肪酸。这些结果表明，在卤虫中发现的抑制活性是由于非酯化的长链脂肪酸及其酯。为了研究脂肪酸对卤虫（Na，K）ATPase的影响，从卤虫中纯化了该酶，并用CHAPS去污剂脱脂.脱脂后，尽管酶上仍留下10-25个磷脂，但活性为。随着外源磷脂的加入，活性恢复。在KCl存在下脱脂的酶比在NaCl存在下脱脂的酶更牢固地使磷脂再结合，脱脂的酶将是研究脂肪酸对（Na，K）ATP酶作用的良好工具

Measurement of levels of (Na,K) ATPase subunit in developing Artemia salinahas indicated that both alpha and beta subunit are present in the embryos of this organism in the early stage of development. Nevertheless, Artemia in these stages does not show any detectable (Na,K)ATPase activity, suggesting that the presence of inhibitors for (Na,K)ATPase in developing Artemia. In this study, the endogenous inhibitors were isolated from Artemia and characterized as follows;1. Digestion of the inhibitors with trypsin or papain did not have any significant effect of their inhibitory activity. Furthermore heat treatment did not affect the inhibitory activity.2. The inhibitors extracted with organic solvent yielded two active spots on TLC plates, both containing longchain fatty acids. These results suggested that the inhibitory activity found in Artemia were due to non-esterified long chain fatty acids and their esters. In order to examine the effect of fatty acids on (Na,K)ATPase, the enzyme was purified from Artemia and delipidated with a detergent, CHAPS.3. Upon delipidation, the activity was although 10-25 phospholipids were still left on an enzyme.4. With the addition of exogeneous phospholipids, the activity was restored. The enzyme delipidated in the presence of KCl reassociated phospholipids more firmly than the enzyme delipidated in the presence of NaCl.The delipidated enzyme would be a good tool for studying the action of fatty acids on (Na,K)ATPase