Morrot G, Zachowski A, Devaux P F
Institut de Biologie Physico-Chimique, Paris, France.
FEBS Lett. 1990 Jun 18;266(1-2):29-32. doi: 10.1016/0014-5793(90)81498-d.
A Mg2(+)-ATPase-enriched fraction was obtained from solubilized human erythrocyte membranes by ammonium sulphate precipitation and anion-exchange chromatography. The solubilized enzyme, of apparent molecular weight 120 kDa, requires phosphatidylserine to be fully active. Phosphatidylethanolamine but not other anionic phospholipids can only partially restore the activity. The Mg-ATPase has a low affinity for Mg2(+)-ATP and is inhibited by fluoride, vanadate, vanadyl and calcium ions. From these characteristics, we infer that this Mg2(+)-ATPase is the same protein as the aminophospholipid translocase which regulates the membrane phospholipid transverse distribution in human erythrocytes by actively transporting aminophospholipids from the outer to the inner monolayer.
通过硫酸铵沉淀和阴离子交换色谱法，从溶解的人红细胞膜中获得了富含Mg2(+)-ATP酶的组分。溶解的酶表观分子量为120 kDa，需要磷脂酰丝氨酸才能完全激活。磷脂酰乙醇胺而非其他阴离子磷脂只能部分恢复活性。Mg-ATP酶对Mg2(+)-ATP的亲和力较低，并受到氟化物、钒酸盐、钒酰离子和钙离子的抑制。从这些特性来看，我们推断这种Mg2(+)-ATP酶与氨基磷脂转位酶是同一种蛋白质，后者通过将氨基磷脂从外单层主动运输到内单层来调节人红细胞膜磷脂的横向分布。
