Phosphorylation of H2O2-treated lens Na+,K+-ATPase

It has been previously shown that H2O2 inhibits lens 86Rb influx and results in modification of Na+,K+-ATPase with respect to ATP hydrolysis. The effect of H2O2 on ATP hydrolysis was further investigated using [gamma-32P]-ATP to examine the Na+,K+-ATPase phosphorylated intermediate. A Na+-dependent phosphorylated polypeptide with an apparent molecular weight of approximately 100 000 was detected in all lens preparations, irrespective of H2O2 treatment. Similar results were observed for partially purified Na+,K+-ATPase from bovine kidney, porcine brain and canine kidney.