酪氨酸酶催化氧化对丝素蛋白结构与性能的影响

Effects of catalytic oxidation with tyrosinase on structure and properties of silk fibroin

采用酪氨酸酶对丝素蛋白催化氧化,考察了酶促氧化反应对丝素蛋白结构及丝素膜性能的影响。研究结果表明,酪氨酸酶可催化氧化丝素蛋白中酪氨酸残基生成多巴和多巴醌结构衍生物,并且两者含量随催化反应时间延长呈波动性变化;酶促反应后丝素蛋白中游离氨基含量下降,丝素风干膜断裂强度增加,表明酶促氧化中丝素大分子间发生自交联。XRD结果表明酪氨酸酶催化氧化对丝素蛋白二级结构有一定影响;SEM显示酶促改性可能影响丝素蛋白冷冻干燥膜多孔形态结构。

The catalytic oxidation of silk fibroins with tyrosinase was carried out. The effects of structure and properties of fibroins with and without enzymatic treatment were investigated. The results indicated that tyrosine residues in silk fibroins could be oxidized to dopa and dopa quinone derivates,the concentrations of the two products varied fluctuation along with the change of time. For the silk fibroins previously treated with tyrosinase,the content of primary amine groups in fibroin decrease and the tensile strength of the air-drying fibroin film increased,which implied that the self-crosslinking occurred between the fibroin molecule during the enzymatic catalytic-oxidation. XRD suggested that the secondary structure of freeze-drying silk fibroins were influenced by the enzymatics,meanwhile,porous morphology of freeze-drying fibroin film was probably affected according to SEM.