On the ouabain-sensitive potassium activated p-nitrophenyl phosphatase activity of vascular muscle plasma membranes.

Sodium-pump ATPase is known to be a cell membrane enzyme being responsible for vectorial transport of Na+ against electrochemical gradient across the plasma membranes of most cell types. In smooth muscles, this Na+-pump ATPase activity is notoriously low and its measurement is complicated by remarkably high level of the basal ATPase activities. In this communication, the properties of ouabain-sensitive, potassium-activated p-nitrophenyl …