Reconstitution of a Calcium Pump with Phospholipids and a Purified Ca++Adenosine Triphosphatase from Sarcoplasmic Reticulum

Vesicles formed from the soluble Ca++-dependent ATPase of sarcoplasmic reticulum and soybean phospholipids catalyzed a rapid uptake of Ca++. This uptake was very sensitive to ionophores for divalent cations, but resistant to ionophores for monovalent cations or to uncouplers of oxidative phosphorylation. Ca++ uptake was also inhibited by chlorpromazine. The reconstituted vesicles, as well as the soluble Ca++-ATPase, catalyzed a Ca++-dependent Pi-ATP exchange, which was sensitive to chlorpromazine.