SCH 28080 is a more selective inhibitor than SCH 32651 at the K+ site of gastric K+/H+-ATPase

Eur J Pharmacol. 1987 Jul 23;139(3):349-52. doi: 10.1016/0014-2999(87)90593-0.

Abstract

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).

MeSH terms

  • Adenosine Triphosphatases / antagonists & inhibitors*
  • Animals
  • Anti-Ulcer Agents / pharmacology*
  • Dogs
  • Gastric Mucosa / enzymology*
  • Guinea Pigs
  • H(+)-K(+)-Exchanging ATPase
  • Imidazoles / pharmacology*
  • In Vitro Techniques
  • Kidney / enzymology
  • Kinetics
  • Potassium / pharmacology*
  • Pyrazines / pharmacology*
  • Sodium-Potassium-Exchanging ATPase / antagonists & inhibitors

Substances

  • Anti-Ulcer Agents
  • Imidazoles
  • Pyrazines
  • Sch 28080
  • 3-amino-2-methyl-8-phenylmethoxyimidazo(1,2-a)pyrazine
  • Adenosine Triphosphatases
  • H(+)-K(+)-Exchanging ATPase
  • Sodium-Potassium-Exchanging ATPase
  • Potassium