title: Studies on direct electron transfer and biocatalytic properties of hemoglobin in polyacrylonitrile matrix.
abstract: The direct electrochemistry of hemoglobin (Hb) immobilized in polyacrylonitrile (PAN) modified glassy carbon electrode was described. The protein-PAN film exhibited a pair of well-defined and quasi-reversible cyclic voltammetric peaks for Hb Fe(III)/Fe(II) redox couple in a pH 7.0 phosphate buffer. The formal potential of Hb heme Fe(III)/Fe(II) couple varied linearly with the increase of pH in the range of 5.0-9.0 with a slope of 54 mV pH(-1), which implied that a proton transfer was accompanied with each electron transfer in the electrochemical reaction. Position of Soret absorption band of Hb-PAN film suggested that the Hb kept its secondary structure similar to its native state in the PAN matrix. The Hb in PAN matrix acted as a biologic catalyst to catalyze the reduction of hydrogen peroxide. The electrocatalytic response showed a linear dependence on the H(2)O(2) concentration ranging from 8.3 x 10(-6) to 5 x 10(-4) mol L(-1) with a detection limit of 8.3 x 10(-6) mol L(-1) at 3 sigma. The apparent Michaelis-Menten constant K(M)(app) for H(2)O(2) sensor was estimated to be 0.9 mmol L(-1).
authors.affiliation: School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Shan
authors.forename: Shanxia
authors.initials: S
authors.lastname: Wang
authors.forename: Daobin
authors.initials: D
authors.lastname: Zhu
authors.forename: Huaiguo
authors.initials: H
authors.lastname: Xue
mesh_terms: D000181:Acrylonitrile / Q000737:chemistry*; D000818:Animals; D002384:Catalysis; D002417:Cattle; D004563:Electrochemistry; D004566:Electrodes; D004579:Electron Transport; D005290:Ferric Compounds / Q000378:metabolism; D005296:Ferrous Compounds / Q000378:metabolism; D006418:Heme / Q000378:metabolism; D006454:Hemoglobins / Q000737:chemistry* / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008027:Light; D010084:Oxidation-Reduction; D011108:Polymers / Q000737:chemistry*; D013057:Spectrum Analysis; D014466:Ultraviolet Rays
chemical_list: D005290:Ferric Compounds; D005296:Ferrous Compounds; D006454:Hemoglobins; D011108:Polymers; D006418:Heme; D006861:Hydrogen Peroxide; D000181:Acrylonitrile