EPR detection of phytophenoxyl radicals stabilized by zinc ions: evidence for the redox coupling of plant phenolics with ascorbate in the H2O2‐peroxidase system

FEBS Letters

Yamasaki, Hideo¹  Grace, Stephen C¹ 

[1] Photobioenergetics Group, Research School of Biological Sciences, The Australian National University, Canberra, ACT 0200, Australia

关键词: Antioxidant;    Chlorogenic acid;    Hydrogen peroxide;    Peroxidase;    Phenylpropanoid;    Electron paramagnetic resonance;    AsA;    ascorbic acid;    APX;    ascorbate peroxidase;    CGA;    chlorogenic acid;    DHA;    dehydroascorbic acid;    EPR;    electron paramagnetic resonance;    GuPX;    guaiacol peroxidase;    HRP;    horseradish peroxidase;    MDA;    monodehydroascorbic acid;    ROIs;    reactive oxygen intermediates;   

DOI  :  10.1016/S0014-5793(98)00048-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Chlorogenic acid (CGA; 3-o-caffeoylquinic acid), a phenylpropanoid metabolite of plants, was oxidized by H₂O₂ in the presence of horseradish peroxidase. The primary and secondary oxidized products both were free radicals which gave EPR multiline signals at g=2.0044 and 2.0042 in the presence of zinc as a spin stabilizing agent. The EPR kinetics showed that ascorbate functioned as a cooperative reductant by regenerating CGA from its corresponding radicals. These results provide evidence to support the idea that the ascorbate-phenolic redox couple in conjunction with guaiacol peroxidase is an efficient H₂O₂ scavenging mechanism in higher plants.

【 授权许可】

Unknown