SCH 28080 is a more selective inhibitor than SCH 32651 at the K+ site of gastric K+/H+-ATPase.
The anti-secretory agents SCH 32651 and SCH 28080 were compared for their potency to interact with the K+ site of guinea-pig parietal cell K+/H+-ATPase and dog kidney Na+/K+-ATPase. SCH 32651 and SCH 28080 had an inhibition constant of 9.0 and 0.02 mumol/l, respectively, for the K+/H+-ATPase. The Ki values for the Na+/K+-ATPase were 140 and 220 mumol/l. The data show that both drugs have a higher affinity to the K+ site of the K+/H+-ATPase than to that of the Na+/K+-ATPase and that the affinity ratio of SCH 28080 in favour of K+/H+-ATPase is much greater (11,000) than that of SCH 32651 (15).
Beil
W
W
Abteilung Allgemeine Pharmakologie, Medizinische Hochschule Hannover, F.R.G.
Staar
U
U
Sewing
K F
KF
D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors*; D000818:Animals; D000897:Anti-Ulcer Agents / Q000494:pharmacology*; D004285:Dogs; D005753:Gastric Mucosa / Q000201:enzymology*; D006168:Guinea Pigs; D017506:H(+)-K(+)-Exchanging ATPase; D007093:Imidazoles / Q000494:pharmacology*; D066298:In Vitro Techniques; D007668:Kidney / Q000201:enzymology; D007700:Kinetics; D011188:Potassium / Q000494:pharmacology*; D011719:Pyrazines / Q000494:pharmacology*; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors
D000897:Anti-Ulcer Agents; D007093:Imidazoles; D011719:Pyrazines; C035235:Sch 28080; C042837:3-amino-2-methyl-8-phenylmethoxyimidazo(1,2-a)pyrazine; D000251:Adenosine Triphosphatases; D017506:H(+)-K(+)-Exchanging ATPase; D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium