title: Thermodynamics of the reduction of NADP with 2-propanol catalyzed by an NADP-dependent alcohol dehydrogenase.
abstract: The apparent equilibrium constant of the biochemical reaction, 2-propanol+NADP(ox) = acetone+NADP(red), was determined at I = 0.25 M over a wide range of pH (5.63 to 8.02) and temperature (5 to 40 degrees C). The reaction was catalyzed by an NADP-dependent alcohol dehydrogenase. The results were used to calculate thermodynamic quantities for the chemical (ionic) reference reaction: 2-propanol+NADP(ox)(3-) = acetone+NADP(red)(4-)+H(+). The thermodynamic quantities for this reference reaction are as follows: equilibrium constant K = (5.98+/-0.46) x 10(-10); standard molar Gibbs energy change Delta(r)G(0) = (52.65+/-0.19) kJmol(-1); standard molar enthalpy change Delta(r)H(0) = (38.9+/-0.6) kJmol(-1); and standard molar entropy change Delta(r)S(0) = -(46.1+/-2.2)J K(-1)mol(-1). All of these results pertain to 25 degrees C (298.15 K) and I = 0. The results also lead, in conjunction with tabulated thermodynamic quantities, to the standard electromotive force E(0) = -0.140 V for the reduction of NADP(ox)(3-) to NADP(red)(4-).
authors.affiliation: Unit of Metabolic Control, Laboratory of Metabolism and Molecular Biology, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, 12501 Washington Avenue, Rockville, MD 20852, USA. tking@niaaa.nih.gov
authors.forename: M Todd
authors.initials: MT
authors.lastname: King
mesh_terms: D019840:2-Propanol / Q000494:pharmacology*; D000426:Alcohol Dehydrogenase / Q000737:chemistry* / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008956:Models, Chemical; D009249:NADP / Q000378:metabolism*; D013696:Temperature; D013816:Thermodynamics
chemical_list: D009249:NADP; D000426:Alcohol Dehydrogenase; D019840:2-Propanol