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    The efficiency of immobilised glutamate oxidase decreases with surface enzyme loading: an electrostatic effect, and reversal by a polycation significantly enhances biosensor sensitivity


    Lowry, John P. and Mc Mahon, Colm and Rocchitta, Gaia and Serra, Pier and Kirwan, Sarah and O'Neill, Robert (2006) The efficiency of immobilised glutamate oxidase decreases with surface enzyme loading: an electrostatic effect, and reversal by a polycation significantly enhances biosensor sensitivity. Analyst, 131. pp. 68-72.

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    Abstract

    The apparent Michaelis constant, KM, for glutamate oxidase (GluOx) immobilised on Pt electrodes increased systematically with enzyme loading. The effect was due, at least in part, to electrostatic repulsion between neighbouring oxidase molecules and the anionic substrate, glutamate (Glu). This understanding has allowed us to increase the Glu sensitivity of GluOx-based amperometric biosensors in the linear response region (100 ± 11 nA cm–2µM–1 at pH 7.4; SD, n = 23) by incorporating a polycation (polyethyleneimine, PEI) to counterbalance the polyanionic protein. Differences in the behaviour of glucose biosensors of a similar configuration highlight a limitation of using glucose oxidase as a model enzyme in biosensor design.

    Item Type: Article
    Keywords: Glutamate oxidase; surface enzyme; electrostatic; polycation; biosensor sensitivity;
    Academic Unit: Faculty of Science and Engineering > Chemistry
    Faculty of Science and Engineering > Research Institutes > Institute of Immunology
    Item ID: 928
    Depositing User: John Lowry
    Date Deposited: 13 Mar 2008
    Journal or Publication Title: Analyst
    Publisher: Royal Society of Chemistry
    Refereed: Yes
    URI:

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