The antibody reacts specifically with human erythrocyte Ca²⁺ pump (Ca²⁺-ATPase, 138 kDa). It may also recognize additional bands at ~215, 160-180, 125, 95-107, 72, and 27 kDa representing products of aggregation or proteolysis of the pump. The antibody does not significantly affect the Ca²⁺ pump activity. The reactivity of the antibody has been mapped to an epitope within amino acid residues 724-783, the region proposed to be the hinge domain of the Ca²⁺-ATPase molecule. It cross-reacts with the Ca²⁺ pump of basolateral membrane of distal convoluted tubules of kidney, hepatocyte plasma membrane, intestine, placenta, endometrium, choroid plexus, Purkinje cells, and hen oviductal tissue using immunohistochemistry and immunoblotting. In human kidney, specific staining is found only along the basolateral membrane of the distal convoluted tubules, while glomeruli and other segments of the nephron do not stain. An additional application with this antibody is immunoaffinity purification of the Ca²⁺ pump.

human erythrocyte Ca²⁺-ATPase.

Calcium ATPase is a transport protein that removes calcium from the cell after muscle contraction. There are two known types, PMCA which is found in the plasma membrane, and the sarcoplasmic reticulum specific protein SERCA.