Oxidative transformation of aminodinitrotoluene isomers by multicomponent dioxygenases
Oxidative transformation of aminodinitrotoluene isomers by multicomponent dioxygenases
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DOI：
10.1128/aem.67.12.5460-5466.2001
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发表时间：
2001-12-01
影响因子：
4.4
通讯作者：
Spain, JC
中科院分区：
文献类型：
--
作者：
Johnson, GR;Smets, BF;Spain, JC
2，4，6-三硝基甲苯（TNT）的吸电子硝基取代基使芳环具有高度的抗氧化转化性。TNT的典型生物转化涉及还原环上的一个或多个硝基以产生相应的胺。TNT的单个硝基取代基还原为氨基取代基显著增加了芳香核的电子密度。氨基二硝基甲苯（ADNT）异构体的相对电子致密的核预计比TNT更容易受到加氧酶的攻击。通过评估三种硝基芳烃双加氧酶羟基化ADNT异构体的能力来测试该假设。主要的反应是环的二氧化，产生亚硝酸盐和相应的氨甲基硝基儿茶酚。次级反应是苄基单加氧形成氨基二硝基苄醇。三种酶的底物偏好和催化特异性差异很大。ADNT异构体是硝基芳烃双加氧酶底物的发现揭示了TNT在有氧条件下广泛细菌转化的潜力。
The electron-withdrawing nitro substituents of 2,4,6-trinitrotoluene (TNT) make the aromatic ring highly resistant to oxidative trans formation. The typical biological transformation of TNT involves reduction of one or more of the nitro groups of the ring to produce the corresponding amine. Reduction of a single nitro substituent of TNT to an amino substituent increases the electron density of the aromatic nucleus considerably. The comparatively electron-dense nuclei of the aminodinitrotoluene (ADNT) isomers would be expected to be more susceptible to oxygenase attack than TNT. The hypothesis was tested by evaluating three nitroarene dioxygenases for the ability to hydroxylate the ADNT isomers. The predominant reaction was dioxygenation of the ring to yield nitrite and the corresponding aminomethylnitrocatechol. A secondary reaction was benzylic monooxygenation to form aminodinitrobenzyl alcohol. The substrate preferences and catalytic specificities of the three enzymes differed considerably. The discovery that the ADNT isomers are substrates for the nitroarene dioxygenases reveals the potential for extensive bacterial transformation of TNT under aerobic conditions.