Sodium-potassium-activated adenosine triphosphatase. IX. The role of phospholipids.
Sodium-potassium-activated adenosine triphosphatase. IX. The role of phospholipids.
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钠钾激活的三磷酸腺苷酶。
DOI：
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发表时间：
1973
影响因子：
4.8
通讯作者：
R. Albers
中科院分区：
文献类型：
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作者：
S. Goldman;R. Albers
摘要Electrophorus electroplax的(Na+ + K+)- atp酶需要磷脂。用Naja Naja毒液的磷脂酶A处理该酶，除去了几乎所有的磷脂，同时丧失了酶活性和形成磷酸化酶的能力。另一方面，产气荚膜梭菌的磷脂酶C消化几乎去除了所有的卵磷脂，三分之二的磷脂酰乙醇胺，而没有磷脂酰丝氨酸。磷脂酶C部分抑制atp酶活性，而磷酸化酶的稳态水平和Na+依赖性核苷酸转磷酸化速率未受到损害。在一定的Mg++水平下，磷脂酶C处理产生E2构象的比例增加；高Mg++对atp酶和对硝基苯磷酸酶的抑制作用在磷脂酶c处理的酶中更为明显。磷脂酶c处理的atp酶的周转减少可能是由于同样的作用。综上所述，磷脂酰丝氨酸是磷酸化酶形成及其去磷酸化的必需物质，而磷脂酰乙醇胺是影响酶对Mg++亲和力的调节剂。
Abstract The (Na+ + K+)-ATPase from Electrophorus electroplax was shown to require phospholipids. Treatment of the enzyme with phospholipase A from Naja naja venom removed almost all phosphatides with concomitant loss of enzymatic activity and of the ability to form phosphoryl enzyme. On the other hand digestion with phospholipase C from Clostridium perfringens removed nearly all of the lecithin, two-thirds of the phosphatidylethanolamine, and none of the phosphatidylserine. ATPase activity was partly inhibited by phospholipase C whereas the steady state level of the phosphoryl enzyme and the rate of the Na+-dependent nucleotide transphosphorylation were not impaired. Phospholipase C treatment produced an increased proportion of the E2 conformation at a given level of Mg++; inhibition of the ATPase and p-nitrophenylphosphatase by high Mg++ were more pronounced with the phospholipase C-treated enzyme. The reduced turnover of the phospholipase C-treated ATPase probably arises from this same effect. It was concluded that phosphatidylserine is a requirement for the formation of phosphoryl enzyme as well as its dephosphorylation, and phosphatidylethanolamine acts as a modifier which influences the affinity of the enzyme for Mg++.