title: Partial uncompetitive inhibition of horseradish peroxidase by a water-miscible ionic liquid [BMIM][MeSO4].
abstract: The ionic liquid, 1-butyl-3-methylimidazolium methylsulfate ([BMIM][MeSO(4)]), was used to investigate the catalytic mechanism of horseradish peroxidase (HRP). The ionic liquid decreased both K(m) and k(cat) values for the HRP-catalyzed oxidation of guaiacol (2-methoxyphenol) by H(2)O(2). These studies imply that [BMIM][MeSO(4)] inhibits the enzyme in an uncompetitive manner. The incorporation of substrate stabilization effects measured by a thermodynamic method into the partial uncompetitive inhibition scheme successfully describes HRP-catalysis in the presence of [BMIM][MeSO(4)], which participates as the inhibitor. The inhibition constant of the ionic liquid was 0.051 M. The turn-over number of the native HRP was almost 14-times higher than that of the HRP-ionic liquid complex indicating that [BMIM][MeSO(4)] does not form a dead-end complex with HRP.
authors.affiliation: School of Chemical Engineering and Bioengineering, College of Engineering, University of Ulsan, Ulsan, Korea.
authors.forename: Jung Hee
authors.initials: JH
authors.lastname: Park
authors.forename: Ik Keun
authors.initials: IK
authors.lastname: Yoo
authors.forename: O Yul
authors.initials: OY
authors.lastname: Kwon
authors.forename: Keungarp
authors.initials: K
authors.lastname: Ryu
mesh_terms: D006139:Guaiacol / Q000378:metabolism; D006735:Horseradish Peroxidase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D006861:Hydrogen Peroxide; D007093:Imidazoles / Q000737:chemistry / Q000494:pharmacology*; D052578:Ionic Liquids / Q000737:chemistry / Q000494:pharmacology*; D007700:Kinetics; D016014:Linear Models; D013463:Sulfuric Acid Esters / Q000737:chemistry / Q000494:pharmacology*
chemical_list: C525963:1-butyl-3-methylimidazolium; D007093:Imidazoles; D052578:Ionic Liquids; D013463:Sulfuric Acid Esters; D006139:Guaiacol; D006861:Hydrogen Peroxide; D006735:Horseradish Peroxidase; C033522:methyl sulfate