TY - JOUR T1 - On the Inhibition of (Na<sup>+</sup> + K<sup>+</sup>)-Activated Adenosine Triphosphatase by Diisopropyl Fluorophosphate JF - Molecular Pharmacology JO - Mol Pharmacol SP - 46 LP - 51 VL - 7 IS - 1 AU - ASIT K. LAHIRI AU - IRWIN B. WILSON Y1 - 1971/01/01 UR - http://molpharm.aspetjournals.org/content/7/1/46.abstract N2 - The (Na+ + K+)-activated transport ATPase from guinea pig kidney cortex is inhibited in the presence of high concentrations of diisopropyl fluorophosphate (DFP) if Mg++ is present, although the inhibition is caused not by DFP but by the fluoride released in its hydrolysis. Fluoride at 1 mM inhibits transport ATPase in a few minutes. The second-order rate constant for inhibition is 2.7 x 102 M-1 min-1. Mg++ is necessary for the inhibition and K+ markedly increases the rate of inhibition, but Na+ is without effect. ATP prevents inhibition by fluoride, and fluoride inhibition can be reversed slowly. 14C-DFP even without Mg++ rapidly labels one or more proteins in the ATPase preparation, but there is no evidence that these proteins are involved in the ATPase activity. ER -