title: Examinations of the Chemical Step in Enzyme Catalysis.
abstract: Advances in computational and experimental methods in enzymology have aided comprehension of enzyme-catalyzed chemical reactions. The main difficulty in comparing computational findings to rate measurements is that the first examines a single energy barrier, while the second frequently reflects a combination of many microscopic barriers. We present here intrinsic kinetic isotope effects and their temperature dependence as a useful experimental probe of a single chemical step in a complex kinetic cascade. Computational predictions are tested by this method for two model enzymes: dihydrofolate reductase and thymidylate synthase. The description highlights the significance of collaboration between experimentalists and theoreticians to develop a better understanding of enzyme-catalyzed chemical conversions.
authors: University of Iowa, Iowa City, IA, United States.
authors: P
authors: P
authors: Singh
authors: University of Iowa, Iowa City, IA, United States.
authors: Z
authors: Z
authors: Islam
authors: University of Iowa, Iowa City, IA, United States. Electronic address: amnon-kohen@uiowa.edu.
authors: A
authors: A
authors: Kohen
mesh_terms: D055162:Biocatalysis; D003198:Computer Simulation; D004926:Escherichia coli / Q000201:enzymology; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008956:Models, Chemical; D013696:Temperature; D013762:Tetrahydrofolate Dehydrogenase / Q000737:chemistry / Q000378:metabolism*; D013940:Thymidylate Synthase / Q000737:chemistry / Q000378:metabolism*
chemical_list: D029968:Escherichia coli Proteins; D013762:Tetrahydrofolate Dehydrogenase; D013940:Thymidylate Synthase
keywords: Commitment to catalysis; Dihydrofolate reductase; Enzyme catalysis; Kinetic complexity; Kinetic isotope effect; Simulations; Thymidylate synthase