title: Quantification and evaluation of kinetic bio-catalytic pathway of horseradish peroxidase in an electron mediated reaction system and its applications in plant extracts.
abstract: The intermolecular coupling of 2,5-dimethoxyaniline (DMA) as mediated electron transfer reaction in presence of H(2)O(2) and peroxidase in acetate buffer of pH 4.2 resulting green colored product having maximum absorption at λ(max)=740 nm was investigated by spectrophotometer. Under optimum conditions, linearity range for the quantification of H(2)O(2) was 2.0-288.0 μM and for peroxidase were 0.59-9.46 and 0.443-9.46 nM by kinetic and fixed-time method, respectively. The catalytic efficiency and catalytic power were K(eff)(D)=2.354 × 10(5)M(-1)min(-1) and K(pow)(D)=4.59 × 10(-4)min(-1), respectively. From the plot of d(1/D(o)) vs d(1/V(o)) and d(1/H(o)) vs d(1/V(o)), Michaelis-Menten constants for DMA and H(2)O(2)were found that K(m)(D)=1,458 μM and [Formula: see text] =301 μM. Applicability of the method was tested for peroxidase activity in some plant extracts and compared with guaiacol/peroxidase system. Regarding superiority of the method, it is suggested that DMA/peroxidase system can be a better hydrogen donor for HRP assay than guaiacol system as evident from kinetic data.
authors.affiliation: Department of Studies in Chemistry, University of Mysore, Manasagangotri, Mysore 570 006, Karnataka, India.
authors.forename: Honnur
authors.initials: H
authors.lastname: Krishna
authors.forename: Padmarajaiah
authors.initials: P
authors.lastname: Nagaraja
authors.forename: Anantharaman
authors.initials: A
authors.lastname: Shivakumar
authors.forename: Nelligere A
authors.initials: NA
authors.lastname: Chamaraja
authors.forename: Narayan
authors.initials: N
authors.lastname: Aradhana
mesh_terms: D000814:Aniline Compounds / Q000378:metabolism*; D031215:Armoracia / Q000201:enzymology*; D004583:Electrons; D057075:Enzyme Assays / Q000379:methods; D006735:Horseradish Peroxidase / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000032:analysis / Q000378:metabolism*; D007700:Kinetics; D008954:Models, Biological; D009195:Peroxidase / Q000378:metabolism; D010936:Plant Extracts / Q000378:metabolism*; D010946:Plants, Medicinal / Q000201:enzymology* / Q000378:metabolism; D013053:Spectrophotometry / Q000379:methods
chemical_list: D000814:Aniline Compounds; D010936:Plant Extracts; D006861:Hydrogen Peroxide; D006735:Horseradish Peroxidase; C121048:guaiacol peroxidase; D009195:Peroxidase