Knowles A F, Eytan E, Racker E
J Biol Chem. 1976 Sep 10;251(17):5161-65.
Ca2+-adenosine triphosphatase from sarcoplasmic reticulum has been delipidated by gel filtration through a Sephadex G-200 column equilibrated with buffer containing cholate. The delipidated Ca2+-adenosine triphosphatase had negligible adenosine triphosphatase activity, but up to 50% of the ATPase activity was restored when the delipidated enzyme was recombined with phosphilipids. It was shown with the delipidated preparation that the phosphorylation of the enzyme by either ATP or Pi was entirely dependent on phospholipids. Among the purified phospholipids, phosphatidylcholine reactivated the adenosine triphosphatase activity better than phosphatidylethanolamine. Vesicles capable of translocating Ca2+ were reconstituted from delipidated Ca2+-adenosine triphosphatase and phosphatidylethanolamine, but not with phosphatidylcholine alone. We conclude that the firmly bound phospholipids which are purified together with the adenosine triphosphatase protein are not essential for the pump since they can be substituted by phosphatidylethanolamine isolated from soybeans.
肌质网的Ca2+ - 三磷酸腺苷酶通过在含有胆酸盐的缓冲液平衡的葡聚糖凝胶G - 200柱上进行凝胶过滤而脱脂。脱脂的Ca2+ - 三磷酸腺苷酶的三磷酸腺苷酶活性可忽略不计，但当脱脂酶与磷脂重新组合时，高达50%的ATP酶活性得以恢复。脱脂制剂表明，该酶被ATP或Pi磷酸化完全依赖于磷脂。在纯化的磷脂中，磷脂酰胆碱比磷脂酰乙醇胺更能有效恢复三磷酸腺苷酶活性。能够转运Ca2+的囊泡由脱脂的Ca2+ - 三磷酸腺苷酶和磷脂酰乙醇胺重构而成，但单独用磷脂酰胆碱则不能。我们得出结论，与三磷酸腺苷酶蛋白一起纯化的紧密结合的磷脂对于泵不是必需的，因为它们可以被从大豆中分离的磷脂酰乙醇胺替代。
