多酚氧化酶法改性蚕丝体系的构建及其构效关系研究

Application of enzyme in modification of polymer materials is one of the hot research topics in the field of macromolecule science. Aiming at the requirement of environmentally friendly and efficient silk modification method, the polyphenol oxidase (PPO) method is creatively put forward for silk fiber modification to prepare high performance ecological silk with anti-bacterial, wrinkle resistance and fire-retardant properties, which will provide a theoretical basis for extending the application of silk in the textile and medical materials and other fields. In this project, laccase and tyrosinase will be applied to catalyze the silk and graft functional compounds. A reasonable, efficient and ecological PPO modified silk fiber system will be constructed and the enzyme kinetics equation of silk enzymatic reaction will be built through the investigation of enzyme stabilization and high efficient catalysis during enzymatic reaction, the enzyme kinetics and the grafting condition of functional compounds onto silk fiber. The amino acid composition, morphology and tertiary structure, crease resistance, anti-bacterial and mechanical properties changes of silk fibers before and after modification will be analyzed. The relationship of structure and the molecular weight of modifiers, the structure of modified silk fibers with the function of silk will be discussed. Accordingly, the structure-function relationship of PPO method modified silk system can be established. The research of this project will provide academic support for silk modification using green enzyme method and will have important reference value to the development of functional and ecological silk fiber and silk fibroin materials.

生物酶用于高分子材料的改性是高分子科学领域的研究热点之一。本项目基于对环保、高效的蚕丝改性方法的需求，创造性地提出采用多酚氧化酶(PPO)法对蚕丝纤维进行改性，制备具有抗皱、抗菌、阻燃等功能的高性能生态蚕丝，为扩大蚕丝在纺织和医用材料等领域的应用提供理论基础。本项目拟采用漆酶和酪氨酸酶催化蚕丝并接枝功能化合物，通过对酶促反应过程中酶的稳定化和高效催化及酶促反应动力学研究，以及对功能化合物接枝蚕丝反应条件的探讨，构建合理、高效、生态的蚕丝PPO酶法改性体系，建立蚕丝PPO酶促反应动力学方程；分析酶促反应及改性前后蚕丝的氨基酸组成、形态和聚集态结构及抗皱、抗菌、机械性能等的变化，探讨改性剂的结构、分子量及改性蚕丝的结构与蚕丝功能性之间的关系，建立PPO酶法改性蚕丝体系的构效关系。本项目的研究将为蚕丝蛋白的绿色酶法改性提供理论支持，并对开发功能性的生态型蚕丝纤维和蚕丝蛋白材料具有重要的参考价值。

生物酶用于高分子的改性是高分子科学领域的研究热点之一。多酚氧化酶是从真菌到植物乃至哺乳动物体内都广泛存在的一类铜蛋白，它能有效催化多酚类化合物氧化形成相应的醌类物质；ε-聚赖氨酸(ε-PLL)是一种含有伯胺基的多肽化合物。.本项目研究了漆酶催化后蚕丝与ε-PLL对蚕丝的改性，优化了改性条件，研究酶促反应及改性前后蚕丝的氨基酸组成、形态等的变化。漆酶催化ε-PLL接枝的真丝织物湿态折皱回复角性能得到很大的改善，对金黄色葡萄球菌具有良好的抗菌性，抑菌率可达99.99%。.以L-酪氨酸和L-多巴两种模型化合物为底物，探讨了酪氨酸酶对蚕丝的反应活性及其反应动力学，优化了酶促反应条件。研究了酪氨酸酶催化蚕丝反应的最佳条件，并对改性后蚕丝的结构及抗皱抗菌性能进行表征和测试。探讨了酪氨酸酶对丝素及丝胶溶液的酶促交联，以成膜的溶失率和断裂强度为评价指标，获得酶促交联丝素和丝胶成膜的较佳反应条件。凝胶电泳结果表明，交联后丝素蛋白分子量增大，充分证明了酪氨酸酶对丝素蛋白的交联作用。酪氨酸酶促交联壳聚糖改性丝素膜具有较好的抗菌性。项目的研究可为扩大蚕丝在纺织和医用材料等领域的应用提供理论基础。