2-氯-1,4-二甲氧基苯阳离子自由基：在茴香醇的木质素过氧化物酶氧化反应中的形成及作用

2-Chloro-1,4-dimethoxybenzene cation radical: formation and role in the lignin peroxidase oxidation of anisyl alcohol.

作者信息

Teunissen P J, Sheng D, Reddy G V, Moënne-Loccoz P, Field J A, Gold M H

机构信息

Department of Food Technology and Nutritional Sciences, Wageningen Agricultural University, 6700 EV Wageningen, The Netherlands.

出版信息

Arch Biochem Biophys. 1998 Dec 15;360(2):233-8. doi: 10.1006/abbi.1998.0940.

DOI:10.1006/abbi.1998.0940

PMID:9851835

Abstract

2-Chloro-1,4-dimethoxybenzene (2Cl-1,4-DMB) oxidation by lignin peroxidase (LiP) proceeds via the formation of the 2Cl-1,4-DMB cation radical as indicated by ESR and UV/vis spectroscopy. The products of the LiP-catalyzed oxidation of 2Cl-1,4-DMB were identified as 2-chloro-1,4-benzoquinone and the dimers dichlorotetramethoxybiphenyl and chloro(chlorodimethoxyphenyl)benzoquinone. The addition of anisyl alcohol (AA) rapidly quenched the 2Cl-1,4-DMB cation radical optical absorption bands, suggesting that the cation radical directly mediates the oxidation of AA. When LiP reactions are conducted in the presence of 50 microM 2Cl-1,4-DMB, the enzyme is inactivated; however, this inactivation can be prevented by the addition of AA. This also suggests that the 2Cl-1,4-DMB cation radical formed in the reaction, in turn, oxidizes AA.

摘要

如电子顺磁共振（ESR）和紫外/可见光谱所示，木质素过氧化物酶（LiP）催化2-氯-1,4-二甲氧基苯（2Cl-1,4-DMB）的氧化过程通过形成2Cl-1,4-DMB阳离子自由基进行。LiP催化2Cl-1,4-DMB氧化的产物被鉴定为2-氯-1,4-苯醌以及二聚体二氯四甲氧基联苯和氯（氯代二甲氧基苯基）苯醌。添加茴香醇（AA）可迅速淬灭2Cl-1,4-DMB阳离子自由基的光吸收带，这表明阳离子自由基直接介导了AA的氧化。当在50微摩尔的2Cl-1,4-DMB存在下进行LiP反应时，该酶会失活；然而，添加AA可防止这种失活。这也表明反应中形成的2Cl-1,4-DMB阳离子自由基反过来会氧化AA。