Effect of Salts on the Activity and Inhibition of E. coli Membrane ATPase by Ethacrynic Acid and Inhibitors
Open Access
- 1 February 1974
- journal article
- research article
- Published by Walter de Gruyter GmbH in Zeitschrift für Naturforschung C
- Vol. 29 (1-2) , 54-59
- https://doi.org/10.1515/znc-1974-1-213
Abstract
The [Mg, Ca]-ATPase activity of E. coli depends on the anion present and follows the chaotropic sequence: Acetate- > HCO3 - > Cl- > I- > NO3 - > SCN-. There are only small differences between the different alkali chlorides. The [Mg, Ca]-ATPase was inhibited by all these salts when the ratio of Mg or Ca to ATP was 1: 5 at pH 9.1. At pH 9.1 or 7.5 and a Mg to ATP ratio of 1 some salts activate and others inhibit the enzyme according to their position in the chaotropic sequence. With Ca the ATPase was activated under these conditions only by acetate. The contradictory activation or inhibition by NaCl or KCl reported by various authors are due to differences in the Mg: ATP ratios used. The inhibition of ATPase by ethacrynic acid, NEM, pCMB. DCCD and azide is much greater at pH 9.1 than at pH 7.5 and is drastically affected by NaCl or KCl.Keywords
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