Separation of Ca2(+)-ATPase from Mg2(+)-ATPase in plasma membrane-rich fraction of bovine parotid gland.
Ca2(+)-ATPase, which does not require Mg2+ for its activation, was separated from Mg2(+)-ATPase by papain treatment of a membrane-rich fraction of bovine parotid gland. The enzyme was partially purified 48-fold by subsequent chromatography on DEAE-cellulose, gel filtration on HPLC, and ion-exchange HPLC. The enzyme showed a molecular weight of 100,000, as estimated by gel filtration on HPLC. The Ca2(+)-ATPase was activated by Ca2+ but not by Mg2+, and this enzyme did not require Mg2+ for its activation by Ca2+. In fact, Mg2+ was inhibitory. p-Nitrophenyl phosphate was not hydrolyzed in the presence of Ca2+ or Mg2+, and this enzyme had no activities of other phosphatases tested. These results suggest that the Ca2(+)-ATPase is a separate enzyme from Mg2(+)-ATPase, Ca2(+)-stimulated Mg2(+)-dependent ATPase, and alkaline phosphatase, all of which are well known to be present in other tissues.
Matsukawa
R
R
Department of Biochemitsry, Nihon University School of Dentistry at Matsudo, Chiba, Japan.
D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000302:isolation & purification*; D000252:Calcium-Transporting ATPases / Q000302:isolation & purification* / Q000378:metabolism; D002417:Cattle; D002462:Cell Membrane / Q000201:enzymology; D010306:Parotid Gland / Q000201:enzymology*; D013379:Substrate Specificity
D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases