Effects of Organic Solvents on the Adenosine Triphosphatase Activity of Erythrocyte Ghosts

Abstract

THE involvement of phospholipids in the adenosine triphosphatase activity of human erythrocytes was demonstrated by Schatzmann¹, who found that treatment with phospholipase C reduced the activity of both the Mg²⁺ and the Na⁺–plus–K⁺–stimulated ATPase. Tatibana² and Ohniishi³ reported a specific inactivation of the Na⁺–plus–K⁺ stimulated ATPase after treatment of ghosts with phospholipase A. The lipids present in freeze-dried red cell ghosts can be distinguished as so-called loosely and strongly bound fractions^4,5. The loosely bound fraction, extracted by ether treatment, contains all the sterols and about 23 per cent of the phospholipids from the human erythrocytes, while the strongly bound lipids, obtained after treatment with ethanol–ether (3 : 1 v/v) consist of phospholipids only⁵. We have investigated the involvement of lipid fractions in the ATPase activities.