Degradation of Lignin Glycosides by Lignin Oxidizing Enzymes

木质素氧化酶对木质素糖苷的降解

基本信息

批准号：
01560188
负责人：
KONDO Ryuichiro
金额：
$ 1.28万
依托单位：
Kyushu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1990
项目状态：
已结题

项目摘要

In order to clarify the effect of the formation of glycoside on the degradation of lignin by enzyme systems, DHP and DHP-glucoside were treated with horseradish peroxidase, laccase and lignin peroxidase. During the oxidation, the reaction mixture of DHP changed color from yellowish to dark brown and finally formed precipitates. On the other hand, the reaction mixture of DHP-Glc just changed color from yellowish to pale brown and formed no precipitate at all. The molecular weight distribution of the control and enzyme treated samples was analyzed by gel filtration chromatography. All molecular weight distribution patterns obtained here showed clearly that oxidation of DHP by enzyme systems containing laccase or peroxidase resulted in polymerization and not degradation of DHP.On the other hand, when DHP-Glc was treated with the enzymes, enzyme-catalyzed depolymerization was observed. Under treatment conditions employed here, DHP-Glc was degraded more extensively into low molecular weight fractions by peroxidase treatment (horseradish peroxidase and lignin peroxidase) rather than laccase treatment (commercial laccase and laccase III). In the present study, we have observed that glucosidic DHP lignin can be degraded by peroxidase and laccase treatments. Although the mechanism for the possible degradation of lignin glycosides in vitro is not elucidated, the present results suggested that there must exist a system where the formation of glycoside prevents polymerization and accelerates efficient degradation reactions.

为了阐明糖苷的形成对酶系统降解木质素的影响，用辣根过氧化物酶、漆酶和木质素过氧化物酶处理DHP和DHP-葡萄糖苷。在氧化过程中，DHP的反应混合物颜色由黄色变为深棕色，最后形成沉淀。另一方面，DHP-Glc的反应混合物的颜色刚刚从黄色变为浅棕色，并且根本没有形成沉淀。通过凝胶过滤色谱分析对照样品和酶处理样品的分子量分布。这里获得的所有分子量分布模式清楚地表明，含有漆酶或过氧化物酶的酶系统对 DHP 的氧化导致 DHP 聚合而不是降解。另一方面，当用酶处理 DHP-Glc 时，观察到酶催化解聚。在此采用的处理条件下，DHP-Glc 通过过氧化物酶处理（辣根过氧化物酶和木质素过氧化物酶）而不是漆酶处理（商业漆酶和漆酶 III）更广泛地降解为低分子量级分。在本研究中，我们观察到糖苷 DHP 木质素可以通过过氧化物酶和漆酶处理来降解。尽管木质素糖苷在体外可能降解的机制尚未阐明，但目前的结果表明，必须存在一个系统，其中糖苷的形成可防止聚合并加速有效的降解反应。