Oxidative cross-linking of pentosans by a fungal laccase and horseradish peroxidase: Mechanism of linkage between feruloylated arabinoxylans
Oxidative cross-linking of pentosans by a fungal laccase and horseradish peroxidase: Mechanism of linkage between feruloylated arabinoxylans
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DOI：
10.1094/cchem.1998.75.2.259
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发表时间：
1998-03-01
期刊：
影响因子：
2.4
通讯作者：
Rouau, X
中科院分区：
文献类型：
--
作者：
Figueroa-Espinoza, MC;Rouau, X
使用毛细管粘度测定法、尺寸排阻 HPLC 和酚类化合物的反相 HPLC 研究了来自真菌 Pycnoporus cinnabarinus 的漆酶交联阿魏酰化可溶性小麦阿拉伯木聚糖的潜力。将漆酶结果与过氧化氢/辣根过氧化物酶系统的结果进行比较。氧化剂导致 0.2% (w/v) 阿拉伯木聚糖溶液的粘度增加。 30分钟后，漆酶形成凝胶。在形成凝胶之前过氧化氢被迅速消耗。游离阿魏酸、阿魏酸甲酯和香草酸抑制凝胶化，而富马酸则没有效果。这表明芳香环，而不是阿魏酸的丙烯链，是阿拉伯木聚糖交联的起始位点。阿魏酸及其 8-O-4'、8-5' 和 5-5' 脱氢二聚体存在于未氧化的阿拉伯木聚糖中。氧化后，出现8-8'和8-5'苯并呋喃脱氢二聚体，并且8-O-4'和8-5'二聚体增加。二聚体的产生与酯结合的阿魏酸的消耗成正比。在交联的阿拉伯木聚糖中，主要二聚体是8-5'苯并呋喃、8-8'和8-O-4'，而5-5'脱氢二聚体保持与未氧化溶液中相同的水平。
The potential of a laccase from the fungus Pycnoporus cinnabarinus to cross-link feruloylated soluble wheat arabinoxylans was investigated using capillary viscometry, size-exclusion HPLC, and reverse-phase HPLC of phenolic compounds. The laccase results were compared with those for a hydrogen peroxide/horseradish peroxidase system. The oxidants provoked an increase in viscosity of a 0.2% (w/v) arabinoxylan solution. A gel was formed after 30 min with laccase. Hydrogen peroxide was consumed rapidly before a gel could be formed. Free ferulic acid, methyl ferulate, and vanillic acid inhibited the gelation, whereas fumaric acid had no effect. This suggests that the aromatic ring, and not the propenoic chain of ferulic acid, was the initiating site for arabinoxylan cross-linking. Ferulic acid and its 8-O-4', 8-5', and 5-5' dehydrodimers were present in nonoxidized arabinoxylans. Upon oxidation, the 8-8' and 8-5' benzofuran dehydrodimers appeared and the 8-O-4' and 8-5' dimers increased. The production of dimers was proportional to the consumption of ester-bound ferulic acid. In cross-linked arabinoxylans, the major dimers were 8-5' benzofuran, 8-8', and 8-O-4', whereas the 5-5' dehydrodimer remained at the same level as in the nonoxidized solution.