Triiodide reduction by cellobiose: quinone oxidoreductase of Phanerochaete chrysosporium

FEBS Letters

Renganathan, V.¹  Bao, Wenjun¹ 

[1]Department of Chemical and Biological Sciences, Oregon Graduate Institute of Science and Technology, 196000 NW Von Neumann Drive, Beaverton, OR 97006-1999, USA

关键词: Cellobiose: quinone oxido reductase;    Cellobiose;    Triiodide;    Peroxidase;    Flavodehydrogenase;    Phanerochaete chrysosporium;    ABTS;    2;    2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid);    CBQase;    cellobiose: quinone oxidoreductase;    DCPIP;    2;    6-dichlorophenol-indophenol;    FPLC;    fast protein liquid chromatography;    HRP;    horseradish peroxidase;    LiP;    lignin peroxidase;    MnP;    manganese peroxidase;   

DOI  :  10.1016/0014-5793(91)80242-U

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Cellobiose: quinone oxidoreductase (CBQase) in the presence of cellobiose inhibits peroxidase-catalyzed oxidation of iodide to triiodide (I₃,⁻). This inhibition is due to the two-electron reduction of I⁻ ₃ by CBQase. The apparent K_m of I⁻ ₃ for this reaction is 120 μM and the specific activity is 57 μmol·min⁻¹·mg⁻¹. A proposed mechanism for I⁻ ₃ reduction by CBQase involves initial reduction of the flavin moiety by cellobiose to produce a dihydroflavin. This is followed by the substitution of one of the iodine atoms of I⁻ ₃ at the C(4a)-position of dihydroflavin to generate C(4a)-iododihydroflavin and two iodide ions. The C(4a)-iododihydroflavin eliminates HI to regenerate the oxidized CBQase.

【 授权许可】

Unknown