A new method of preparation of Ca<SUP>2+</SUP> -ATPase from sarcoplasmic reticulum: extraction with octylglucoside

A fast method for preparing Ca<SUP>2+</SUP>-ATPase from rabbit muscle sarcoplasmic reticulum was devised. The method involves extracting extrinsic membrane proteins with the non-ionic detergent octylglucoside at high salt concentration. A Ca<SUP>2+</SUP> ATPase of consistently high specific activity (about 25 &#956;moles/mg.min) is found in the insoluble residue. The method was optimized with respect to the concentrations of detergent and salt, pH, and other extraction conditions. By the criteria of the protein pattern in SDS-polyacrylamide gel electrophoresis, dependence of the hydrolytic activity on the presence of Ca<SUP>2+</SUP>, and the phosphoprotein formation, the preparation is identical with the Ca<SUP>2+</SUP>-ATPase isolated previously by MacLennan [10] and other authors. The main advantages of the new method are its rapidity, its reliability, and the high specific activity of the purified enzyme