Open AccessThe ATPase of Bacillus alcalophilus
Author(s) -
HOFFMANN Artur,
DIMROTH Peter
Publication year - 1990
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1990.tb15635.x
Subject(s) - cooperativity , atpase , protein subunit , enzyme , membrane , gel electrophoresis , chemistry , biochemistry , chromatography , methanol , escherichia coli , antiserum , biology , antigen , organic chemistry , genetics , gene
The ATPase of Bacillus alcalophilus was extracted from the bacterial membranes with Triton X‐100 and purified by hydroxyapatite column chromatography. SDS gel electrophoresis of the purified protein indicated the typical subunit pattern of an F 1 F 0 structure with five F 1 subunits (α,β,γ,δ,ɛ) and three F 0 subunits (a,b,c). The α and β subunits were antigens for an antiserum against the corresponding subunits of the ATPase of Escherichia coli. Subunit c was extracted from the bacterial membranes with chloroform/methanol. Its amino acid composition was in the range of subunits c from other ATPases. Maximal ATPase activity was observed in the presence of 2–5 mM MgCl 2 , an ATP/Mg 2+ ratio of 2:1 and 25% methanol. In the absence of methanol, only about 1% of the maximal activity was observed. The enzyme was also activated by Ca 2+ (in the absence of methanol), reaching about 30% of the maximal activity. The dependence of initial velocity versus ATP of the Ca 2+ ‐activated but not of the Mg 2+ /methanol‐activated enzyme indicated cooperativity with three strongly cooperative binding sites.