Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9882187 | Archives of Biochemistry and Biophysics | 2005 | 9 Pages |
Abstract
The effect of guanidinium hydrochloride (GdnHCl) on multisite and unisite ATPase activity by F0F1 of submitochondrial particles from bovine hearts was studied. In particles without control by the inhibitor protein, 50Â mM GdnHCl inhibited multisite hydrolysis by about 85%; full inhibition required around 500Â mM. In the range of 500-650Â mM, GdnHCl enhanced the rate of unisite catalysis by promoting product release; it also increased the rate of hydrolysis of ATP bound to the catalytic site without GdnHCl. GdnHCl diminished the affinity of the enzyme for aurovertin. The effects of GdnHCl were irreversible. The results suggest that disruption of intersubunit contacts in F0F1 abolishes multisite hydrolysis and stimulates of unisite hydrolysis. Particles under control by the inhibitor protein were insensitive to concentrations of GdnHCl that induce the aforementioned alterations of F0F1 free of inhibitor protein, indicating that the protein stabilizes the global structure of particulate F1.
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Authors
Marietta Tuena de Gómez-Puyou, Lenin DomÃnguez-RamÃrez, Gerardo Pérez-Hernández, Armando Gómez-Puyou,