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首页> 外文期刊>Biochemistry >LIGNIN PEROXIDASE-CATALYZED OXIDATION OF SULFONATED AZO DYES GENERATES NOVEL SULFOPHENYL HYDROPEROXIDES
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LIGNIN PEROXIDASE-CATALYZED OXIDATION OF SULFONATED AZO DYES GENERATES NOVEL SULFOPHENYL HYDROPEROXIDES

机译：木质素过氧化物酶催化的磺化偶氮染料的氧化生成新的亚硫基氢化过氧化物

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摘要

Lignin peroxidase (LiP) is an extracellular enzyme produced by the lignin-degrading fungus Phanerochaete chrysosporium and is involved in azo dye degradation by this organism. In this study, LiP oxidation of the sulfonated azo dyes 4-(4'-sulfophenylazo)-2,6-dimethylphenol (I), Orange II [1-(4'-sulfophenylazo)-2-naphthol] (II), a dimethyl analog of Orange II [1-(2',6'-dimethyl-4'-sulfophenylazo)-2-naphthol] (III), and 4-(4'-sulfonamidophenylazo)-2,6-dimethylphenol (IV) was examined. Azo dye I was oxidized to 2,6-dimethyl-1,4-benzoquinone and 4-sulfophenyl hydroperoxide. Orange II (II) was oxidized to 1,2-naphthoquinone and 4-sulfophenyl hydroperoxide. The dimethyl analog of Orange II (III) was oxidized to 1,2-naphthoquinone and 2,6-dimethyl-4-sulfophenyl hydroperoxide. Azo dye IV was oxidized predominantly to 2,6-dimethyl-1,4-benzoquinone and another product, tentatively characterized as 4-sulfonamidophenyl hydroperoxide. In the O-18-labeling studies with O-18(2), oxygen incorporation into the phenyl hydroperoxides from the oxidation of I and III was observed. A mechanism for azo dye degradation consistent with product identification and the O-18-labeling studies is proposed. Two successive one-electron oxidations of the phenolic ring of an azo dye by the H2O2-oxidized forms of LiP produces a carbonium ion. Then water attacks the phenolic carbon bearing the azo linkage, producing an unstable hydroxy intermediate which breaks down to yield a quinone and a sulfo- or sulfonamidophenyldiazene. The phenyldiazene is oxidized by O-2 to generate the corresponding phenyldiazene radical, which eliminates N-2 to yield a sulfo- or sulfonamidophenyl radical. O-2 scavenges the latter to yield the corresponding hydroperoxide. This is the first report on the production and identification of a phenyl hydroperoxide in any chemical or biological system.
机译：木质素过氧化物酶（LiP）是由木质素降解真菌Phanerochaete chrysosporium产生的细胞外酶，并参与该生物降解偶氮染料。在这项研究中，LiP氧化了磺化偶氮染料4-（4'-磺基苯基偶氮）-2,6-二甲基苯酚（I），橙II [1-（4'-磺基苯基偶氮）-2-萘酚]（II），橙色II [1-（2'，6'-二甲基-4'-磺基苯基偶氮）-2-萘酚]（III）和4-（4'-磺酰胺基苯基偶氮）-2,6-二甲基苯酚（IV）的二甲基类似物为检查。偶氮染料I被氧化为2，6-二甲基-1，4-苯醌和4-磺苯基氢过氧化物。将橙II（II）氧化为1,2-萘醌和4-磺苯基氢过氧化物。橙II（III）的二甲基类似物被氧化为1,2-萘醌和2,6-二甲基-4-磺苯基氢过氧化物。偶氮染料IV主要被氧化为2,6-二甲基-1,4-苯醌和另一种产物，暂定为4-磺酰氨基苯基氢过氧化物。在使用O-18（2）进行O-18标记的研究中，观察到I和III的氧化将氧结合到苯基氢过氧化物中。提出了一种与产品鉴定和O-18标记研究一致的偶氮染料降解机理。 LiP的H2O2氧化形式对偶氮染料的酚环进行两次连续的单电子氧化，生成碳鎓离子。然后水侵蚀带有偶氮键的酚碳，生成不稳定的羟基中间体，该中间体分解生成醌和磺基或磺酰胺基苯基二氮烯。苯基二氮烯被O-2氧化，生成相应的苯基二氮烯基，该自由基将N-2消除，生成磺基或磺酰胺基苯基。 O-2清除后者，得到相应的氢过氧化物。这是有关在任何化学或生物系统中生产和鉴定过氧化苯的第一份报告。

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