title: The soluble adenosine triphosphatase of Thiobacillus ferrooxidans.
abstract: Adenosine triphosphatase (ATPase) from Thiobacillus ferrooxidans was purified 55-fold. Polyacrylamide gel electrophoresis of the most purified fraction showed only one major band; histochemical analysis showed that the ATPase activity was associated with this band. The pH optimum is 9-10. The enzyme hydrolyzed ATP stoichiometrically to ADP and inorganic phosphate, the Km for this substrate being 7.75 times 10-3 M. GTP and ITP are alternate substrates, the Km values for these being 6.71 times 10-3 M and 3.12 times 10-3 M, respectively. ADP is slightly hydrolyzed. Magnesium, manganese, and calcium can serve as cofactors; Km values for these are 2.0 times 10-3 M, 9.4 times 10-4 M, and 8.0 times 10-4 M, respectively. The enzyme activity was not activated by either sodium or potassium, but a combination of the two ions were inhibitory. Azide and p-hydroxymercuribenzoate strongly inhibited the enzyme activity, whereas cyanide, dinitrophenol, and N,N'-dicyclohexylcarbodiimide (DCCD) were without effect. The enzyme was cold labile at 0 degrees-C, but was more stable at 18-24 degrees-C.
mesh_terms: D000244:Adenosine Diphosphate / Q000096:biosynthesis; D000249:Adenosine Monophosphate / Q000096:biosynthesis; D000251:Adenosine Triphosphatases / Q000302:isolation & purification / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D001386:Azides / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D002458:Cell Fractionation; D002848:Chromatography, DEAE-Cellulose; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D006863:Hydrogen-Ion Concentration; D006902:Hydroxymercuribenzoates / Q000494:pharmacology; D008274:Magnesium / Q000494:pharmacology; D008345:Manganese / Q000494:pharmacology; D008970:Molecular Weight; D010710:Phosphates / Q000096:biosynthesis; D012995:Solubility; D013855:Thiobacillus / Q000201:enzymology*
chemical_list: D001386:Azides; D006902:Hydroxymercuribenzoates; D010710:Phosphates; D000249:Adenosine Monophosphate; D008345:Manganese; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D008274:Magnesium; D002118:Calcium