Dynamic disorder in single-molecule Michaelis-Menten kinetics: the reaction-diffusion formalism in the Wilemski-Fixman approximation.
Single-molecule equations for the Michaelis-Menten [Biochem. Z. 49, 333 (1913)] mechanism of enzyme action are analyzed within the Wilemski-Fixman [J. Chem. Phys. 58, 4009 (1973); 60, 866 (1974)] approximation after the effects of dynamic disorder--modeled by the anomalous diffusion of a particle in a harmonic well--are incorporated into the catalytic step of the reaction. The solution of the Michaelis-Menten equations is used to calculate the distribution of waiting times between successive catalytic turnovers in the enzyme beta-galactosidase. The calculated distribution is found to agree qualitatively with experimental results on this enzyme obtained at four different substrate concentrations. The calculations are also consistent with measurements of correlations in the fluctuations of the fluorescent light emitted during the course of catalysis, and with measurements of the concentration dependence of the randomness parameter.
Chaudhury
Srabanti
S
Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India.
Cherayil
Binny J
BJ
D000465:Algorithms; D002384:Catalysis; D003198:Computer Simulation; D004058:Diffusion; D004798:Enzymes / Q000737:chemistry* / Q000378:metabolism; D007700:Kinetics; D008027:Light; D008954:Models, Biological; D008968:Molecular Conformation; D013379:Substrate Specificity; D001616:beta-Galactosidase / Q000737:chemistry / Q000378:metabolism
D004798:Enzymes; D001616:beta-Galactosidase