title: Electron-transfer reactivity and enzymatic activity of hemoglobin in a SP Sephadex membrane.
abstract: Hemoglobin can exhibit a direct electron-transfer reaction after being entrapped in a SP Sephadex membrane. A pair of stable and well-defined redox waves are obtained at a hemoglobin-SP sephadex modified pyrolytic graphite electrode. The anodic and cathodic peak potentials are located at -0.244 and -0.336 V (vs SCE), respectively. On the other hand, the peroxidase activity of the protein in the membrane is also greatly enhanced. The apparent Michaelis-Menten constant is calculated to be 1.9 mM, which shows a large catalytic activity of hemoglobin in the SP Sephadex membrane toward hydrogen peroxide (H2O2). According to the direct electron-transfer property and enhanced peroxidase activity of Hb in the membrane, a Hb/SP Sephadex membrane-based H2O2 biosensor is prepared, with a linear range approximately 5.0 x 10(-6) to 1.6 x 10(-4) mol/L.
authors.affiliation: Department of Biochemistry and National Laboratory of Pharmaceutical Biotechnology, Nanjing University, PR China.
authors.forename: C
authors.initials: C
authors.lastname: Fan
authors.forename: H
authors.initials: H
authors.lastname: Wang
authors.forename: S
authors.initials: S
authors.lastname: Sun
authors.forename: D
authors.initials: D
authors.lastname: Zhu
authors.forename: G
authors.initials: G
authors.lastname: Wagner
authors.forename: G
authors.initials: G
authors.lastname: Li
mesh_terms: D000818:Animals; D015374:Biosensing Techniques; D002384:Catalysis; D002417:Cattle; D003911:Dextrans / Q000737:chemistry*; D004563:Electrochemistry; D004579:Electron Transport; D004800:Enzymes, Immobilized / Q000737:chemistry; D006454:Hemoglobins / Q000737:chemistry*; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D010544:Peroxidases / Q000737:chemistry
chemical_list: D003911:Dextrans; D004800:Enzymes, Immobilized; D006454:Hemoglobins; C025614:sephadex; D010544:Peroxidases