半胱氨酸为还原剂从兔毛纤维中提取角蛋白

Keratin Was Extracted from Rabbit Hair Using L-cystein as Reductive Agent

摘要:

以L-半胱氨酸为还原剂从兔毛纤维中提取角蛋白，在最佳提取条件：pH=10.5，L-半胱氨酸浓度0.165mol/L、尿素浓度8mol/L、反应时间5h、反应温度75℃，兔毛纤维溶解率高达74.12%。溶解液通过透析、冷冻干燥后，得到的角蛋白回收率为69.23%，角蛋白质量分数高达99.38%。通过SDS-聚丙烯酰胺电泳（SDS-PAGE）测定兔毛角蛋白的相对分子质量主要集中在11kDa左右。利用XRD、FTIR、拉曼光谱以及差示扫描量热仪（DSC）表征分析角蛋白内部结构，结果表明，随着兔毛纤维的溶解，L-半胱氨酸破坏了兔毛大分子链中35%（摩尔分数）的二硫键，导致角蛋白的二级结构发生变化，α-螺旋结构含量减少，α-结晶区含量降低，β-折叠结构含量增加。

Abstract:

Keratin was extracted from rabbit hair using L-cystein as reductive agent under the condition which is pH=10.5，L-cystein 0.165 mol/L，urea 8mol/L，reaction time 5h，reaction temperature 75℃. The results of the experiments presented the dissolution rate of rabbit hair was 74.12%，the recovery rate of final keratin after disdialysis and freeze drying of dissolved solution was 69.23%，in which the mass fraction of keratin was as high as 99.38%. The molecular weight of rabbit hair keratin mainly concentrated in about 11 kDa via polyacrylamide electrophoresis SDS-PAGE.The internal structure of Keratin was characterized by infrared spectrum (FTIR)， Raman spectroscopy，X-ray diffraction (XRD) and differential scanning calorimetry (DSC). From the result，with the process of rabbit hair dissolution，about 35% (in mole fraction)disulfide bond in the rabbit hair was destoried by L-cystein，which resulted in the change of keratin secondary structure in which the content of α-helix structure decreased，and the content of β-sheet increased.