Application of Poly[oxyethylene(dimethylimino)propyl-(dimethylimino)ethylene] as Enzyme Stabilizer for Bilirubin Oxidase Immobilized Electrode

Abstract

It has been shown that polyammonium cations comprising quaternary ammonium and hydrophilic groups such as amide and hydroxyl groups stabilize a redox enzyme bilirubin oxidase (BOD). The BOD catalyzes the reaction: 4[Fe(CN)6] 4-+ 4H + + O2 → 4[Fe(CN)6] 3-+ 2H2O, and has been a promising enzyme for use as a cathode catalyst in biofuel cells. In this study, the stabilizing effect of poly[oxyethylene(dimethylimino)propyl(dimethylimino)ethylene] (PA1) on BOD has been investigated. The sample solution containing BOD and the PA1 salt was kept at a given temperature, and the loss of the enzymatic activity was detected after given stored times. The activity decreased exponentially with stored time so that the first-order rate-constant of inactivation was determined. The inactivation rate-constant lowered with increasing the concentration of the PA1 salt, suggesting that BOD was stabilized by the association with the PA1 cation. The PA1 cation may act like a protective colloid or decrease the local disorder of BOD by its wrapping. A membrane-covered electrode containing BOD, PA1, and [Fe(CN)6] 4-/3-in the internal solution phase was examined in air-saturated aqueous solution. The electrode gave a well-defined current-potential curve with a steady state limiting current due to the PA1-[Fe(CN)6] 4-/3-polyion complex-mediated bioelectrocatalytic current for the reduction of O2. The decreasing of the steady state limiting current became slower in the presence of the PA1 salt, indicating again the stabilizing effect of PA1 cation on BOD.

Kinetic Study of the Thermal Inactivation of Glucose Oxidase in the Presence of Denaturant and Stabilizer by Means of Bioelectrocatalysis Method

“…7,8 The cationic polymers adsorb onto the negative charges of BOD surface to form polyion complexes, by which the local disorder of the surface may be reduced. The GOD molecule also carries negative charges on the surface.…”

Colorimetric Microtiter Plate Assay of Polycationic Aminoglycoside Antibiotics in Culture Broth Using Amaranth

“…However, the precipitate gave higher A520-values than predicted, suggesting that the composition of the precipitate is complex. Cationic polymers containing quaternary ammonium groups, such as poly(diallyldimethylammonium chloride) and poly[oxyethylene(dimethylimino)propyl-(dimethylimino)ethylene chloride] 18 were precipitated with the AR 3-anion, but the precipitates were not dissolved in the basic solution.…”

Analytical Methods for the Detection and Purification of ε-Poly-L-lysine for Studying Biopolymer Synthetases, and Bioelectroanalysis Methods for Its Functional Evaluation

“…12,13 The stabilizing effect can be ascribed to electrostatic association of the cationic polymers with the negative charges of the enzyme surface to form a polyion complex species stable in solution. The effect can be studied by a bioelectroanalysis method in which the inactivation process is followed by the enzymatic bioelectrocatalytic current.…”