Regulation of the gastric microsomal (H+ + K+)-transporting ATPase system by the endogenous activator. Effect of phospholipase A2 treatment.
Pig gastric microsomal (H+ + K+)-stimulated ATPase activity was nearly abolished within 10 min of digestion with phospholipase A2 at room temperature. The enzyme activity could be largely restored by a cytosolic activator protein partially purified from the gastric cells. The K+ sensitivity and turnover of 32P-labelled intermediates produced by the control and the activator-reconstituted microsomal (H+ + K+)-stimulated ATPase were closely similar but were widely different to those from treated membranes without activator reconstitution. The data suggest an essential requirement for the endogenous activator for gastric (H+ + K+)-stimulated ATPase function.
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D004789:Enzyme Activation / Q000187:drug effects; D005753:Gastric Mucosa / Q000187:drug effects / Q000201:enzymology*; D017506:H(+)-K(+)-Exchanging ATPase; D008861:Microsomes / Q000187:drug effects / Q000201:enzymology*; D010740:Phospholipases / Q000494:pharmacology*; D010741:Phospholipases A / Q000494:pharmacology*; D054467:Phospholipases A2; D013552:Swine
D010740:Phospholipases; D010741:Phospholipases A; D054467:Phospholipases A2; D000251:Adenosine Triphosphatases; D017506:H(+)-K(+)-Exchanging ATPase