The high-affinity Ca(2+)-ATPase from rat parotid plasma membranes is an ectoenzyme: solubilization and characterization of the Ca(2+)-ATPase activity.

A high-affinity Ca(2+)-ATPase was solubilized from rat parotid plasma membranes and purified by concanavalin A and DEAE-cellulose chromatography. The properties of the purified high-affinity Ca(2+)-ATPase are very different from those of the parotid plasma membrane ATP-dependent Ca2+ pump but appear to be similar to those of a rat liver cell adhesion protein which exhibits high-affinity ecto-Ca(2+)-ATPase activity.