title: Electrochemical oxidation of cholesterol catalyzed by cholesterol oxidase with use of an artificial electron mediator.
abstract: Several redox dyes of phenazine and phenothiazine derivatives including 1-methoxy-5-methylphenazinium methosulfate (MPMS), thionin, azure A, and azure C work well as electron acceptors for reduced cholesterol oxidase (EC 1.1.3.6) (ChOx). Kinetic parameters and equilibrium constants of the enzymatic oxidation of cholesterol obtained suggest that the molecular size and/or hydrophobicity of the redox dyes determines their abilities as the electron acceptors. The electrochemical sensitivity to cholesterol in the detection system using ChOx and the above-mentioned redox compounds is determined by the electron acceptability of the redox compounds, and the employment of either MPMS or thionin allows electrochemical determination of cholesterol at a low electrode potential (0 V vs SCE) in the concentration range 0.25-2.5 mmol dm(-3), which covers that in normal human blood.
authors.affiliation: Department of Applied Chemistry, Faculty of Engineering, Osaka University, Yamada-oka 2-1, Suita, Osaka 565, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Nakaminami
authors.forename: S
authors.initials: S
authors.lastname: Kuwabata
authors.forename: H
authors.initials: H
authors.lastname: Yoneyama