蚕丝蛋白—丝胶和丝素凝胶特性的比较

Comparison of Gel Properties between the Silk Proteins (Bombyx mori)——Sericin and Fibroin

丝胶的胶凝速度快于丝素，而其凝胶强度较弱．丝胶受到热水的作用会产生凝胶－溶液的相互转化，而丝素不发生此现象．这是两者的结构和组成不同所致．丝素凝胶的β结构明显高于丝胶凝胶．丝素亲水性氨基酸含量少，氢键的形成、分子向β结构转化所需时间长，胶凝速度就慢；而一旦成为凝胶后，由于其β结构、结晶度较高，且在热水中不发生向溶液的转化，故为非可逆性凝胶．相反，丝胶由于亲水性氨基酸含量多，氢键易于形成，向β结构转化而发生胶凝作用，在热水中，氢键极易离解而转化成溶液。

Gelation speed of sericin is quicker than that of fibroin,but the strength of sericin gel is weaker than that of fibroin. The sericin gel can be transformed into solution in hot water,but the fibroin gel can not. This indicates the difference in their structures and compositions. βstructure in sericin gel is less than the fibroin gel,and the content of hydrophilic amino acids in fibroin is less,so longer period is required for the formation of hydrogen bonds and βstructure. Therefore,gelation speed of fibroin is slower.In addition,gelsol transition of fibroin is difficult due to the formation of βstructure and high crystality in the gel. Thus fibroin gel has been considered as an irreversible gel.But the content of hydrophilic amino acids in sericin is higher,the gel is formed when a network structure is produced by these hydrophilic amino acids. But these network structures in gel are easy to be broken in hot water and transformed into solution. So sericin gel can be considered as a reversible gel.