Na,K-dependent adenosine triphosphate phosphohydrolase: activation of the phosphatase reaction by ATP analogs.
The effect of N1-substituted analogs of ATP on the hydrolysis of umbelliferone phosphate by Na,K-ATPase has demonstrated: analogs having a negatively charged substituent (N1-oxy- or N1-carbo-methoxy-ATP) and capable of accepting H+ induce an activation similar to that of ATP; N1-methoxy-ATP, containing an uncharged substituent, does not affect the phosphatase reaction at low concentration and inhibits it at higher concentration. It has been assumed that ATP binding to Na,K-ATPase induces formation of a hydrogen bond between the nitrogen atom at the first position of the purine base and appropriate amino acid of active centre, with a subsequent attachment of H+ to ATP, thus facilitating the transition of Na,K-ATPase from the K+- to the Na+-form.
D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D004372:Ducks; D004789:Enzyme Activation; D007700:Kinetics; D012491:Salt Gland / Q000201:enzymology; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
D000255:Adenosine Triphosphate; D000254:Sodium-Potassium-Exchanging ATPase