Kerem Z, Hammel K E
Institute for Microbial and Biochemical Technology, USDA Forest Products Laboratory, Madison, WI 53705, USA.
FEBS Lett. 1999 Mar 5;446(1):49-54. doi: 10.1016/s0014-5793(99)00180-5.
We have identified key components of the extracellular oxidative system that the brown rot fungus Gloeophyllum trabeum uses to degrade a recalcitrant polymer, polyethylene glycol, via hydrogen abstraction reactions. G. trabeum produced an extracellular metabolite, 2,5-dimethoxy-1,4-benzoquinone, and reduced it to 2,5-dimethoxyhydroquinone. In the presence of 2,5-dimethoxy-1,4-benzoquinone, the fungus also reduced extracellular Fe3+ to Fe2+ and produced extracellular H2O2. Fe3+ reduction and H2O2 formation both resulted from a direct, non-enzymatic reaction between 2,5-dimethoxyhydroquinone and Fe3+. Polyethylene glycol depolymerization by G. trabeum required both 2,5-dimethoxy-1,4-benzoquinone and Fe3+ and was completely inhibited by catalase. These results provide evidence that G. trabeum uses a hydroquinone-driven Fenton reaction to cleave polyethylene glycol. We propose that similar reactions account for the ability of G. trabeum to attack lignocellulose.
我们已经确定了褐腐真菌卧孔菌（Gloeophyllum trabeum）用于通过氢提取反应降解难降解聚合物聚乙二醇的细胞外氧化系统的关键成分。卧孔菌产生了一种细胞外代谢物2,5-二甲氧基-1,4-苯醌，并将其还原为2,5-二甲氧基氢醌。在2,5-二甲氧基-1,4-苯醌存在的情况下，该真菌还将细胞外的Fe3+还原为Fe2+，并产生细胞外过氧化氢。Fe3+的还原和过氧化氢的形成均源于2,5-二甲氧基氢醌与Fe3+之间的直接非酶反应。卧孔菌对聚乙二醇的解聚既需要2,5-二甲氧基-1,4-苯醌，也需要Fe3+，并且会被过氧化氢酶完全抑制。这些结果证明卧孔菌利用氢醌驱动的芬顿反应来裂解聚乙二醇。我们认为类似的反应解释了卧孔菌攻击木质纤维素的能力。
