title: Log P effect of organic solvents on a thermophilic alcohol dehydrogenase.
abstract: An alcohol dehydrogenase from the hyperthermophilic archaeon Aeropyrum pernix was activated by water-miscible organic solvents. This activation was influenced by the kind and the concentration of the added organic solvents. The k(cat) was increased by a factor of over ten when the mole fraction of acetonitrile was 0.1. This effect was large when organic solvents with large log P values were added. In fact, the k(cat) showed a strong positive correlation with the log P value of the mixed solvent at a constant mole fraction of water, while it was not affected by the kind of organic solvents added. Both the activation enthalpy and the entropy decreased with an increase in log P. The contribution of the activation enthalpy to the free energy of activation was larger than that of the activation entropy, and the free energy of activation decreased with an increase in log P.
authors.affiliation: Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Hidehiko
authors.initials: H
authors.lastname: Hirakawa
authors.forename: Noriho
authors.initials: N
authors.lastname: Kamiya
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Kawarabayashi
authors.forename: Teruyuki
authors.initials: T
authors.lastname: Nagamune
mesh_terms: D041522:Aeropyrum / Q000201:enzymology*; D000426:Alcohol Dehydrogenase / Q000737:chemistry*; D019843:Archaeal Proteins / Q000737:chemistry*; D006358:Hot Temperature; D009243:NAD / Q000737:chemistry; D009930:Organic Chemicals / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry*; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
chemical_list: D019843:Archaeal Proteins; D009930:Organic Chemicals; D012997:Solvents; D014867:Water; D009243:NAD; D000426:Alcohol Dehydrogenase