密粘褶菌Gloeophyllum trabeum胞外低分子量多肽的分离纯化及其对纤维素生物降解作用

The Purification and Role in Fungal Oxidative Cellulose Degradation of a Low Molecular Weight Peptide from Brown-rot Fungi Gloeophyllum trabeum

通过HPLC高效液相层析由褐腐真菌中能强烈降解木质纤维素的代表菌株密粘褶菌Gloeo phyllumtrabeum的胞外培养液 ,分离纯化得到一低分子量的活性多肽组分 (Gt因子 ) .Gt因子具有较好热稳定性 ,在pH 2 5～ 6 5范围内保持稳定 .Gt因子分子量在 4 0 0 0左右 ,等电点pI 6 6 .Gt因子具有络合Fe3 + 的能力 ,且能够将Fe3 + 还原为Fe2 + .在O2 存在时 ,能以纤维素物质为电子供体形成羟基自由基HO·.利用循环伏安法 ,观察到Gt因子与纤维素底物之间的氧化还原过程 .研究表明 ,Gt因子极有可能在褐腐菌的纤维素降解初期起着重要的作用 .

A novel low-molecular weight peptide (Gt factor) was isolated and purified from the extracellular culture of brown-rot fungi Gloeophyllum trabeum. It had a high thermal stability, a molecular weight of 4 000 and pI of 6.6. Gt factor remained active under pH 2.5—6.5 and had a high Fe 3+ -chelating ability and the capability of reducing Fe 3+ to Fe 2+ . In the presence of O 2, HO · free radicals were produced with cellulosic materal as an electron donor. Cyclic voltammetry ( CV) was used to study the electron transfer between Gt factor and cellulosic substrate. All experimental results indicate that Gt factor might play an important role in the early stage of cellulose biodegradation by brown-rot fungi.