SDS-PAGE分析辽宁法库叶茂台出土辽代丝绸的老化特征

为了解辽宁法库叶茂台出土辽代丝绸的老化程度,应用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳法(简称SDS-PAGE)分析辽代丝绸蛋白质的相对分子量,并依据与现代蚕丝蛋白质组成分子量的对比结果来探讨辽代丝绸的老化特征。SDS-PAGE结果表明辽代丝绸蚕丝蛋白质残留着相对分子量为65kD和56kD两条肽链,而蚕丝蛋白质通常含有的25kD轻链蛋白却并不存在,其丝绸组成已经发生了明显变化,说明辽代丝绸糟朽严重,并经进一步分析认为65kD和56kD两条肽链是蚕丝蛋白质重链(390kD)断裂的产物,而25kD蛋白的消失则推测辽丝绸蛋白非结晶区域肽链或已分解,或已降解为更小分子量的的肽链。X射线衍射结果分析表明由于蚕丝蛋白非结晶区域肽段降解速度明显快于结晶区域,致使埋藏于地下多年的辽代蚕丝蛋白结晶度反而大于现代蚕丝。

Study on the aging characteristics of Liao Dynasty silk excavated fromYemaotai,Faku,Liaoning by SDS-PAGE

In order to estimate the degree of aging of Liao Dynasty silk,excavated from the Faku Yemaotai Tomb in Liaoning,sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was adopted to analyze the relative molecular weights of silk proteins.The results were compared with modern silk protein to explore the aging characteristics of the Liao Dynasty silk.The SDS-PAGE results showed that the Liao Dynasty silk protein had two peptide chains,65kD and 56kD.The 25kD light chain,which usually exists in silk protein,was not found.The protein structures of the Liao Dynasty silk show significant changes,indicating serious aging.Further analysis found that the two peptide chains of 65kD and 56kD were the fragmentation products of the silk protein heavy chain (390kD),while the disappearance of 25kD protein suggested that the peptide chains in the non-crystalline region had broken down,or had been degraded into smaller peptide chains.X-ray diffraction analysis showed that the non-crystalline region peptides degraded much faster than did the crystalline region peptides. Therefore,the degree of crystallization of Liao Dynasty silk,which has been buried for many years,is higher than that of modern silk.