Chemoselective Nitro Group Reduction and Reductive Dechlorination Initiate Degradation of 2-Chloro-5-Nitrophenol by Ralstonia eutropha JMP134
Chemoselective Nitro Group Reduction and Reductive Dechlorination Initiate Degradation of 2-Chloro-5-Nitrophenol by Ralstonia eutropha JMP134
复制标题
DOI：
10.1128/aem.65.6.2317-2323.1999
复制
发表时间：
1999-06
影响因子：
4.4
通讯作者：
A. Schenzle;H. Lenke;J. Spain;H. Knackmuss
中科院分区：
文献类型：
--
作者：
A. Schenzle;H. Lenke;J. Spain;H. Knackmuss
Ralstonia eutropha JMP134利用2-氯-5-硝基苯酚作为氮、碳和能量的唯一来源。对2-氯-5-硝基苯酚的初始降解步骤与对3-硝基苯酚的降解步骤类似。2-氯-5-硝基苯酚最初被还原为2-氯-5-羟胺苯酚，经酶催化班贝格重排生成2-氨基-5-氯对苯二酚。2-氨基-5-氯对苯二酚中的氯通过还原机制脱除，生成氨基对苯二酚。2-氯-5-硝基酚和3-硝基酚诱导3-硝基酚硝基还原酶、3-羟胺酚变化酶的表达和脱氯活性。3-硝基酚硝基还原酶在NADPH存在下催化芳香硝基化学选择性还原为羟胺基。3-硝基酚硝基还原酶对多种单、二、三硝基芳香族化合物具有活性，表明该酶对底物的特异性较弱。亚硝苯作为酶的底物，比硝基苯转化得更快。
ABSTRACT Ralstonia eutropha JMP134 utilizes 2-chloro-5-nitrophenol as a sole source of nitrogen, carbon, and energy. The initial steps for degradation of 2-chloro-5-nitrophenol are analogous to those of 3-nitrophenol degradation in R. eutropha JMP134. 2-Chloro-5-nitrophenol is initially reduced to 2-chloro-5-hydroxylaminophenol, which is subject to an enzymatic Bamberger rearrangement yielding 2-amino-5-chlorohydroquinone. The chlorine of 2-amino-5-chlorohydroquinone is removed by a reductive mechanism, and aminohydroquinone is formed. 2-Chloro-5-nitrophenol and 3-nitrophenol induce the expression of 3-nitrophenol nitroreductase, of 3-hydroxylaminophenol mutase, and of the dechlorinating activity. 3-Nitrophenol nitroreductase catalyzes chemoselective reduction of aromatic nitro groups to hydroxylamino groups in the presence of NADPH. 3-Nitrophenol nitroreductase is active with a variety of mono-, di-, and trinitroaromatic compounds, demonstrating a relaxed substrate specificity of the enzyme. Nitrosobenzene serves as a substrate for the enzyme and is converted faster than nitrobenzene.