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[32] The glucose oxidase—catalase system

1976; Academic Press; Linguagem: Inglês

10.1016/s0076-6879(76)44034-x

1557-7988

James C. Bouin, Mokhtar T. Atallah, Herbert O. Hultin,

Electrochemical Analysis and Applications

Publisher Summary This chapter discusses the immobilization and assay procedure of the glucose oxidase–catalase system. Glucose oxidase is a glycoprotein having a molecular weight of approximately 150,000–180,0001; it contains 2 moles of flavin adenine dinucleotide per mole of enzyme and 11–16% carbohydrates. It has a pH optimum of approximately 5.5 to 5.7. The rate of oxidation of β-D-glucose is about 157 times faster than that of α-D-glucose. Important considerations in any assay technique, therefore, are the anomeric form of glucose present, the rate of mutarotation in the system compared to the rate of the reaction, and the extent of the reaction being measured. Glucose oxidase has been assayed manometrieally, polarographically, by differential conductivity, and by a coupled colorimetric assay involving peroxidase and o-dianisidine. A sensitive spectrofluorometrie analysis of H 2 O 2 has been developed using diacetyl dichlorofluorescein, which has possibilities of being adapted for the assay of GO x . The polarographic and conductivity methods avoid the difficulties of direct spectrophotometric assays when using particular matter in the assay mixture.