title: Modified Michaelis law in a two-state ratchet model for a molecular motor as a function of diffusion constant.
abstract: We study transport properties and energetics of ratchets, which are driven by a chemical reaction between two states with different diffusion constants. We find that velocity curves show very sensitive dependence on the ratio of diffusion constants, whereas the rate of Adenosinetriphosphate (ATP) consumption curves depends smoothly on it. Modified Michaelis-Menten law shows us that identical values of Michaelis-Menten constant K(M) can be obtained independently from both curves. We obtain force-velocity curves for different values of a ratio of diffusion constants. We find that the Michaelis-Menten constant increases with the increasing external load for the "active site" model where the ATP assisted transition occurs at the localized region near the minimum of the ratchet potential, whereas it decreases with the increasing load for the "delocalized model."
authors.affiliation: Department of Physics, Myongji University, Yongin 449-728, Korea.
authors.forename: Hye Young
authors.initials: HY
authors.lastname: Moon
authors.forename: Youngah
authors.initials: Y
authors.lastname: Park
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry*; D001665:Binding Sites; D055592:Biophysical Phenomena; D001703:Biophysics; D004058:Diffusion; D006868:Hydrolysis; D007700:Kinetics; D011487:Protein Conformation
chemical_list: D000255:Adenosine Triphosphate