酪氨酸酶催化儿茶素接枝丝素蛋白及其抗氧化性研究

Enzymatic grafting of catechin onto silk fibroins with tyrosinase and its antioxidant performance

以儿茶素为天然抗氧化剂,借助于酪氨酸酶的催化氧化作用,将儿茶素与丝素蛋白伯胺基反应,进行丝织物生物改性加工。以分光光度法考察儿茶素在丝织物表面的吸附/接枝效果,测定织物色度、紫外防护因子(UPF)、抗氧化性(DPPH法)及机械性能变化,评价酶促儿茶素与丝素蛋白接枝效果。研究结果表明,酪氨酸酶能催化儿茶素氧化生成颜色较深的醌类产物;丝织物经酶促儿茶素处理后较对照样色深增加,UPF增加,机械性能变化较小;儿茶素处理和酪氨酸酶/儿茶素组合处理均能提高丝织物对DPPH自由基的清除效果,其中后者具有较好抗氧化耐洗性。

Enzymatic modification of silk fibroin was carried out by using tyrosinase and a natural antioxidant of catechin via covalent reaction between catechin and primary amine groups of silk fibroins. Spectrophotometry was used to evaluate the efficacy of adsorption and grafting of catechin onto the fibroin surfaces. The parameters like color depth,UPF value,antioxidant ability（ DPPH method） and mechanical behavior for the catechin-treated silk fabrics were investigated,respectively. The results indicated that catechin could be enzymatically oxidized and conversed into dark quinone products. The color depth and UPF value for the treated sample were higher than those of the control,while less strengthen changes were detected before and after enzymatic treatments. Furthermore,both catechin treatment and tyrosinase / catechin treatment improved the antioxidant ability of silk fabrics against DPPH radical,more satisfactory result was achieved for the sample based on the combined treatment with tyrosinase and catechin.