[Interaction of p-nitrophenylphosphate with Na+,K+-ATPase].
The vector characteristics of the interacting Na+, K+-ATPase and ouabaine were studied in experiments on the restored ghosts of erythrocytes. It is shown that the effect of K+ on the enzyme activity is the same as in cases of using ATP and p-nitrophenylphosphate (p-NPP) as phosphorylating agents. ADP removes the p-NPP induced inhibition with ouabain. This effect is explained rather by addition of ADP to the enzyme substrate centre than by a decrease in the concentration of E1 approximately P phosphoform. Incorporation of labelled orthophosphate into p-nitrophenol (NP) in the presence of Na+, K+-ATPase preparations was not detected. It is shown that antibodies against the fraction of the brain microsomes inhibit K+-NPPases to a much less extent than Na+, K+-ATPase. The digitonin treatment does not remove (Na++ATP)-dependent increase in the K+-NPPase activity. A conclusion is drawn that the mechanisms of p-NPP hydrolysis differs from the mechanism of ATP hydrolysis.
D000818:Animals; D004910:Erythrocyte Membrane / Q000201:enzymology; D007700:Kinetics; D009596:Nitrophenols / Q000494:pharmacology; D009943:Organophosphorus Compounds / Q000494:pharmacology; D010042:Ouabain / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D000254:Sodium-Potassium-Exchanging ATPase / Q000097:blood*
D009596:Nitrophenols; D009943:Organophosphorus Compounds; C008644:nitrophenylphosphate; D010042:Ouabain; D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium
Izuchenie vzaimodeistviia n-nitrofenilfosfata s Na+,K+-ATP-azoĭ.