title: Peroxidase activity of cationic metalloporphyrin-antibody complexes.
abstract: Peroxidase activity of a complex of water-soluble cationic metalloporphyrin with anti-cationic porphyrin antibody is reported. Antibody 12E11G, which was prepared by immunization with a conjugate of 5-(4-carboxyphenyl)-10,15,20-tris(4-methylpyridyl)porphine iodide (3MPy1C), bound to tetramethylpyridylporphyrin iron complex (FeIII-TMPyP) with the dissociation constant of 2.6 x 10(-7) M. The complex of antibody 12E11G with FeIII-TMPyP catalyzed oxidation of pyrogallol, catechol, and guaiacol. A Lineweaver-Burk plot for the oxidation of pyrogallol catalyzed by the FeIII-TMPyP-antibody complex showed Km=8.6 mM and kcat=680 min(-1). Under the same conditions, Km and kcat for horseradish peroxidase (HRP) were 0.8 mM and 1750 min(-1), respectively. Although the binding interaction of the antibody to the substrates was one order lower than that of native HRP, the peroxidase activity of this system was in the same order of magnitude as that of HRP.
authors.affiliation: Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Yamaguchi
authors.forename: Kaori
authors.initials: K
authors.lastname: Tsubouchi
authors.forename: Kazuhide
authors.initials: K
authors.lastname: Kawaguchi
authors.forename: Eri
authors.initials: E
authors.lastname: Horita
authors.forename: Akira
authors.initials: A
authors.lastname: Harada
mesh_terms: D000911:Antibodies, Monoclonal / Q000737:chemistry* / Q000378:metabolism; D000918:Antibody Specificity; D000936:Antigen-Antibody Complex / Q000737:chemistry* / Q000378:metabolism; D002384:Catalysis; D002412:Cations; D007700:Kinetics; D008665:Metalloporphyrins / Q000737:chemistry* / Q000276:immunology; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010544:Peroxidases / Q000737:chemistry* / Q000378:metabolism; D011748:Pyrogallol / Q000737:chemistry
chemical_list: D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D002412:Cations; D008665:Metalloporphyrins; D011748:Pyrogallol; D010544:Peroxidases