Partial purification and characterization of the human erythrocyte Mg2(+)-ATPase. A candidate aminophospholipid translocase.
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.
Morrot
G
G
Institut de Biologie Physico-Chimique, Paris, France.
Zachowski
A
A
Devaux
P F
PF
D001693:Biological Transport, Active; D017301:Ca(2+) Mg(2+)-ATPase / Q000037:antagonists & inhibitors / Q000097:blood*; D002352:Carrier Proteins / Q000097:blood*; D004910:Erythrocyte Membrane / Q000201:enzymology* / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008563:Membrane Lipids / Q000378:metabolism; D008565:Membrane Proteins / Q000097:blood*; D008970:Molecular Weight; D010714:Phosphatidylethanolamines / Q000097:blood*; D010718:Phosphatidylserines / Q000097:blood*; D049294:Phospholipid Transfer Proteins; D013379:Substrate Specificity
D002352:Carrier Proteins; D008563:Membrane Lipids; D008565:Membrane Proteins; D010714:Phosphatidylethanolamines; D010718:Phosphatidylserines; D049294:Phospholipid Transfer Proteins; D017301:Ca(2+) Mg(2+)-ATPase