title: A minimum catalytic unit of F1-ATPase shows non-cooperative ATPase activity inherent in a single catalytic site with a Km 70 microM.
abstract: F1-ATPase has three interacting catalytic sites and shows complicated kinetics. Here, we report reconstitution of a complex, most likely composed of one alpha subunit and one beta subunit, with a single catalytic site from thermophilic Bacillus PS3 F1-ATPase on the solid surface. The complex has an ATPase activity which obeys a simple non-cooperative kinetics with a Km(ATP) of 70 microM and a Vmax of 0.1 unit/mg. Different from F1-ATPase, the complex is not inactivated by 7-chrolo-4-nitrobenzofrazan. Thus, the inherent activity attributable to a single catalytic site unaffected by other catalytic sites of F1-ATPase is characterized.
authors.affiliation: Research Laboratory of Resources Utilization, Tokyo Institute of Technology, Yokohama, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Saika
authors.forename: M
authors.initials: M
authors.lastname: Yoshida
mesh_terms: D009327:4-Chloro-7-nitrobenzofurazan; D000255:Adenosine Triphosphate / Q000378:metabolism; D001407:Bacillus / Q000201:enzymology; D001665:Binding Sites; D002384:Catalysis; D007700:Kinetics; D011487:Protein Conformation; D006180:Proton-Translocating ATPases / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000255:Adenosine Triphosphate; D006180:Proton-Translocating ATPases; D009327:4-Chloro-7-nitrobenzofurazan