Open AccessA Na + K + ‐Activated Mg 2+ ‐Dependent ATPase Released from Proteus L‐Form Membrane
Author(s) -
Monteil Henri,
Schoun Josiane,
Guinard Marie
Publication year - 1974
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1974.tb03293.x
Subject(s) - atpase , divalent , bacillus megaterium , chemistry , tris , escherichia coli , enzyme , proteus vulgaris , membrane , biochemistry , adenosine triphosphate , bacteria , biology , organic chemistry , gene , genetics
The membrane‐associated, Na + K + ‐activated, Mg 2+ ‐dependent adenosine 5′‐triphosphatase activities of Proteus P 18 L‐forms were further characterized. The enzyme was solubilized from membrane ghosts by repeated washings in a Mg 2+ ‐free 33 mM Tris‐HCl buffer pH 7.5. Solubilized Mg 2+ ‐dependent ATPase exhibits an initial increase in activity, followed by a fairly rapid inactivation at 0 °C. Proteus L‐form ATPase exhibits allotopic properties as seen in Micrococcus lysodeikticus, Streptococcus faecalis, Bacillus megaterium and Escherichia coli. The two monovalent cations (K + and Na + ) taken alone or together and the one divalent cation (Ca 2+ ) were activators. The ATPase is highly specific for ATP as a substrate. ADP is a competitive inhibitor. N,N '‐Dicyclohexylcarbodiimide, a known inhibitor of mitochondrial ATPase, of mitochondrial oxidative phosphorylation and of the membrane‐bound ATPase of Streptococcus faecalis , was found to inhibit both the membrane‐bound and the solubilized form of Proteus L‐form ATPase.