title: Tunneling and coupled motion in the Escherichia coli dihydrofolate reductase catalysis.
abstract: H-transfer was studied in the complex kinetic cascade of dihydrofolate reductase. Intrinsic kinetic isotope effects, their temperature dependence, and other temperature-dependent parameters indicated H-tunneling, but no 1 degrees to 2 degrees coupled motion. The data also suggested environmentally coupled tunneling and commitment to catalysis on pre-steady-state isotope effects.
authors.affiliation: Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, USA.
authors.forename: R Steven
authors.initials: RS
authors.lastname: Sikorski
authors.forename: Lin
authors.initials: L
authors.lastname: Wang
authors.forename: Kelli A
authors.initials: KA
authors.lastname: Markham
authors.forename: P T Ravi
authors.initials: PT
authors.lastname: Rajagopalan
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Benkovic
authors.forename: Amnon
authors.initials: A
authors.lastname: Kohen
mesh_terms: D002384:Catalysis; D004926:Escherichia coli / Q000201:enzymology* / Q000378:metabolism; D007700:Kinetics; D013762:Tetrahydrofolate Dehydrogenase / Q000378:metabolism*
chemical_list: D013762:Tetrahydrofolate Dehydrogenase