title: Application of polyammonium cations to enzyme-immobilized electrode: application as enzyme stabilizer for bilirubin oxidase.
abstract: Bilirubin oxidase was stored in the solutions containing polyammonium salts for a given time at 30 degrees C, and the activity was assayed. The enzyme catalyzes the reaction: 4[Fe(CN)6]4- + 4H+ + O2 --> 4[Fe(CN)6]3- + 2H2O, and the activity can be measured by the absorbance at the wavelength for the absorption maxima of [Fe(CN)6)]3-. The results show that polyammonium cations comprising quaternary ammonium in the main chain and hydrophilic groups, such as hydroxyl and amide groups, stabilize the enzyme in solution. These polyammonium cations may act like a protective colloid. The membrane-covered electrode containing the polyammonium cations, the enzyme, and [Fe(CN)6]4-/3- in the internal solution phase was constructed. The electrode gave a well-defined current-potential curve with a steady state limiting current due to the polycation-[Fe(CN)6]4-/3- complex-mediated bioelectrocatalytic current for the reduction of O2. The time-dependent decrease of the limiting current indicates again the stabilizing effect of the polyammonium cations on the enzyme.
authors.affiliation: Department of Bioscience, Fukui Prefectural University, Japan. hajime@fpu.ac.jp
authors.forename: Hajime
authors.initials: H
authors.lastname: Katano
authors.forename: Hirosuke
authors.initials: H
authors.lastname: Tatsumi
authors.forename: Takao
authors.initials: T
authors.lastname: Hibi
authors.forename: Tokuji
authors.initials: T
authors.lastname: Ikeda
authors.forename: Toshihide
authors.initials: T
authors.lastname: Tsukatani
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D004563:Electrochemistry; D004566:Electrodes; D004795:Enzyme Stability; D004800:Enzymes, Immobilized; D010084:Oxidation-Reduction; D044925:Oxidoreductases Acting on CH-CH Group Donors / Q000032:analysis* / Q000378:metabolism; D011073:Polyamines / Q000737:chemistry*; D000071228:Polyelectrolytes; D000644:Quaternary Ammonium Compounds / Q000737:chemistry
chemical_list: D004800:Enzymes, Immobilized; D044925:Oxidoreductases Acting on CH-CH Group Donors; D011073:Polyamines; D000071228:Polyelectrolytes; D000644:Quaternary Ammonium Compounds; C042401:bilirubin oxidase