title: Biocatalytic oxidation of phenolic compounds by bovine methemoglobin in the presence of H2O2: quantitative structure-activity relationships.
abstract: In the present work, 13 p-substituted phenols with different functional groups have been systematically evaluated as metHb substrates by means of HPLC analysis. Non-hyperbolic kinetics were observed and Hill coefficients in the 0.37-1.00 range were obtained. The catalytic constants and the Hill coefficients were found to be quantitatively correlated with two independent variables: the energy level of the highest-occupied molecular orbital (E(HOMO)), which describes the intrinsic redox activity of the substrates and the pK(a)-values, which are related to substrate ionization. Oxygen evolution in the presence of each phenol derivative was also measured, and good correlation between peroxidase-like and catalase-like activities of the protein was observed. It is also shown that bovine metHb, although less active than other peroxidases, may represent a good alternative from an economical point of view for phenol removal processes. The equations here obtained may serve as a basis to further explore the potential use of metHb-mediated reactions in the treatment of phenols in wastewaters and to predict which phenol will be removed most efficiently under this treatment with satisfactory reliability.
authors.affiliation: Department of Physical Chemistry, University of Castilla-La Mancha, Campus Universitario, E-02071 Albacete, Spain. MariaTeresa.Perez@uclm.es
authors.forename: M Teresa
authors.initials: MT
authors.lastname: Pérez-Prior
authors.forename: Rafael
authors.initials: R
authors.lastname: Gómez-Bombarelli
authors.forename: M Isabel
authors.initials: MI
authors.lastname: González-Sánchez
authors.forename: Edelmira
authors.initials: E
authors.lastname: Valero
mesh_terms: D000818:Animals; D055162:Biocatalysis; D002417:Cattle; D006861:Hydrogen Peroxide / Q000737:chemistry*; D007700:Kinetics; D008706:Methemoglobin / Q000737:chemistry*; D010084:Oxidation-Reduction; D010636:Phenols / Q000737:chemistry / Q000302:isolation & purification*; D021281:Quantitative Structure-Activity Relationship; D062065:Wastewater / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*
chemical_list: D006861:Hydrogen Peroxide; D008706:Methemoglobin; D010636:Phenols; D062065:Wastewater; D014874:Water Pollutants, Chemical