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Purification and characterization of the F/sub 1/-ATPase form Clostridium thermoaceticum

Journal Article · · J. Bacteriol.; (United States)
OSTI ID:5811395
The F/sub 1/ portion of the H/sup +/ -ATPase from Clostridium thermoaceticum was purified to homogeneity by solubilization at low ionic strength, ion-exchange chromatography, and gel filtration. The last indicated the M/sub r/ to be 370,000. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the pure enzyme revealed four bands with M/sub r/ corresponding to 60,000, 55,000, 37,000, and 17,000 in an apparent molar ratio of 3:3:1:1. The purified enzyme would bind to stripped membranes to reconstitute dicyclohexylcarbodiimide-sensitive ATPase activity. Phosphohydrolase activity, measured at 58/sup 0/C, was optimal at pH 8.5. In the presence of a 1 mM excess of Mg/sup 2 +/ over the concentration of ATP, the K/sub m/ for ATP was 0.4 mM, and the V/sub max/ was 6.7 ..mu..mol min /sup -1/ mg/sup -1/. Unlike the membrane-bound F/sub 1/F/sub 0/ complex, the F/sub 1/-ATPase was relatively insensitive to the inhibitors dicyclohexylcarbodiimide and tributyltin chloride. Both the complex and the F/sub 1/-ATPase were inhibited by quercetin, azide, 7-chloro-4-nitro-benz-2-oxa-1,3-diazole, and free magnesium, and both were stimulated by primary alcohols and sulfite. In whole cells, the F/sub 1/F/sub 0/-ATPase catalyzed the synthesis of ATP in response to a pH gradient.
Research Organization:
Univ. of Georgia, Athens
DOE Contract Number:
AS09-79ER10499
OSTI ID:
5811395
Journal Information:
J. Bacteriol.; (United States), Journal Name: J. Bacteriol.; (United States) Vol. 165:1; ISSN JOBAA
Country of Publication:
United States
Language:
English