Department of Chemistry, Chemical Engeeneering and Material, University of L'Aquila, Via Vetoio, I-67100 Coppito, L'Aquila, Italy.
Chemistry. 2010 May 25;16(20):6077-87. doi: 10.1002/chem.200903302.
Model coniferyl alcohol lignin (the so-called dehydrogenative polymerisate, DHP) was produced in water under homogeneous conditions guaranteed by the presence of a micellised cationic surfactant. A complete study of the activity of the enzymatic system peroxidase/H(2)O(2) under our reaction conditions was reported and all the reaction products up to the pentamer were characterised by (1)H NMR spectroscopy and ESI mass spectrometry. Our system, and the molecules that have been generated in it, represent a closer mimicry of the natural microenvironment since an enzyme, under micellar conditions, reproduces the cell system better than in buffer alone. On the basis of the oligomers structures a new biosynthetic perspective was proposed that focused attention on a coniferyl alcohol dimeric quinone methide as the key intermediate of the reaction. A formal, strictly alternate sequence of a radical and an ionic step underlines the reaction, thus generating ordered oligolignols structures. Alternatively to other model lignins, our olignols present a lower degree of radical coupling between oligomeric units. This offers a closer biosynthetic situation to the observation of a low rate of radical generation in the cell wall.
模型松柏醇木质素（所谓的脱氢聚合物，DHP）在水相条件下，通过存在胶束化的阳离子表面活性剂，在均相条件下生成。我们报道了在我们的反应条件下过氧化物酶/H(2)O(2)酶促系统的活性的完整研究，并用（1）H NMR 光谱和 ESI 质谱法对所有反应产物（直至五聚体）进行了表征。我们的系统，以及在其中生成的分子，代表了对天然微环境的更接近模拟，因为在胶束条件下，酶比单独在缓冲液中更能复制细胞系统。基于低聚物的结构，提出了一个新的生物合成观点，该观点将注意力集中在松柏醇二聚醌甲醚作为反应的关键中间体上。自由基和离子步骤的正式、严格交替序列强调了反应，从而生成有序的低聚木质素结构。与其他模型木质素不同，我们的低聚体在低聚物单元之间的自由基偶联程度较低。这提供了一个更接近的生物合成情况，观察到细胞壁中自由基生成的速率较低。
