Effects of ethylenediaminetetra-acetate and deoxycholate on kinetic constants of the calcium ion-dependent adenosine triphosphatase of human erythrocyte membranes.

severe problem: when they are able to degrade a membrane structure, the structure of a membranebound enzyme may be altered simultaneously. This may result not simply in an inactivation of an enzyme (e.g. Mg2+-ATPase; Schoner et al., 1967; J0rgensen & Skou, 1969) but rather in an alteration of some, e.g. kinetic, properties. The present paper describes some results on the side effects ofEDTA and deoxycholate on the kinetic properties of Ca2+-ATPase (EC 3.6.1.3), from human erythrocyte membranes, produced when these compounds were used in the purification of this enzyme. The studies were performed to test the suitability of EDTA and deoxycholate as an aid in the purification procedure for Ca2+-ATPase of human erythrocyte membranes in comparison with a method published previously (Wolf, 1970, 1972).