Article ID Journal Published Year Pages File Type
9616804 Journal of Molecular Catalysis B: Enzymatic 2005 8 Pages PDF
Abstract
2,6-Dichloroindophenol (DCIP) is shown to be utilised efficiently as electron acceptor replacing dioxygen in the reaction of Trigonopsis variabilisd-amino acid oxidase (TvDAO) with d-methionine as the substrate. The specificity constant for DCIP reduction at 30 °C is one-twelfth that of oxygen conversion into hydrogen peroxide. Time course analysis of simultaneous consumption of DCIP and dioxygen, recorded on-line by absorption and non-invasive fluorescence quenching, respectively, pinpoints the preferential utilisation of dioxygen; and reveals a maximum DCIP conversion rate that is independent of the initial concentration of dioxygen. A robust direct assay of TvDAO activity has been developed that does not require anaerobic reaction conditions. It was down-scaled to microtitre plate format and overcomes practical limitations of other assays due to the low affinity of TvDAO for dioxygen (Km ≈ 0.7 mmol L−1).
Related Topics
Physical Sciences and Engineering Chemical Engineering Catalysis
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