Some properties of an adenosine triphosphatase obtained from beef corneal epithelium

Abstract

A partially purified ATPase preparation obtained from beef corneal epithelium was studied. The dialyzed enzyme had an absolute requirement for Mg++, and a Mg: ATP ratio of 1:1 appears to be necessary for optimum reaction. The enzyme was stimulated by the addition of low concentrations of KCl, NaCl, and choline chloride. Higher concentrations of the salts, however, decreased the activity observed in the presence of MgCl2 alone. NaCl increased the inhibition caused by KCl and vice versa. Ouabain had no effect, but N-ethylmaleimide, EDTA, and CaSO4 decreased the activity of the enzyme.