Steady-state kinetic mechanism of LodA, a novel cysteine tryptophylquinone-dependent oxidase

    Authors

    E. Sehanobish; S. Shin; A. Sanchez-Amat;V. L. Davidson

    Comments

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    Abbreviated Journal Title

    FEBS Lett.

    Keywords

    Amine oxidase; Cofactor; Quinoprotein; Lysine oxidase; Redox enzyme; QUINOHEMOPROTEIN AMINE DEHYDROGENASE; PROTEIN LYSINE OXIDASE; MARINOMONAS-MEDITERRANEA; PARACOCCUS-DENITRIFICANS; LYSYL OXIDASE; TRYPTOPHAN TRYPTOPHYLQUINONE; METHYLAMINE DEHYDROGENASE; EPSILON-OXIDASE; COFACTOR; PURIFICATION; Biochemistry & Molecular Biology; Biophysics; Cell Biology

    Abstract

    LodA is a novel lysine-epsilon-oxidase which possesses a cysteine tryptophylquinone cofactor. It is the first tryptophylquinone enzyme known to function as an oxidase. A steady-state kinetic analysis shows that LodA obeys a ping-pong kinetic mechanism with values of k(cat) of 0.22 +/- 0.04 s (1), K-lysine of 3.2 +/- 0.5 mu M and K-O2 of 37.2 +/- 6.1 mu M. The k(cat) exhibited a pH optimum at 7.5 while k(cat)/K-lysine peaked at 7.0 and remained constant to pH 8.5. Alternative electron acceptors could not effectively substitute for O-2 in the reaction. A mechanism for the reductive half reaction of LodA is proposed that is consistent with the ping-pong kinetics. (C) 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

    Journal Title

    Febs Letters

    Volume

    588

    Issue/Number

    5

    Publication Date

    1-1-2014

    Document Type

    Article

    Language

    English

    First Page

    752

    Last Page

    756

    WOS Identifier

    WOS:000331717500017

    ISSN

    0014-5793

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