链霉菌B221的角蛋白降解机制初探

利用本实验室自行分离得到的链霉菌B221液体发酵分解羽毛角蛋白,在第2d到第3d角蛋白降解最为迅速,5d后角蛋白降解率达到82.7%。发酵液的无细胞上清液中检测到角蛋白酶活,最大酶活出现在第4d。在角蛋白降解率与角蛋白酶活之间的不完全对应,揭示可能还存在非酶降解途径。硫酸盐是角蛋白降解过程中硫元素的主要转化形式。同时在发酵液中检测到亚硫酸盐,其含量变化与酶活、降解率、可溶性蛋白、巯基化合物的变化存在很强的相关性,表明亚硫酸盐在角蛋白降解中可能起到非常关键的作用。链霉菌B221降解角蛋白的过程中不但存在角蛋白酶降解途径,而且存在非酶降解途径—亚硫酸分解作用。

Mechanism of Keratin Degradation by Streptomycete sp.B221

Streptomycete sp. B221 was cultured on chicken feather in a mineral solution. The degrading rate reached maxium from 2nd day to 3rd day and reached as much as 82.7% at 5th day. Keratinase activity was detected in the supernatant of the medium and the largest enzyme activity occurred at 4th day. The incomplete correspondence between the keratin degrading rate and keratinase activity revealed the existence of non-enzymatic degradation pathway of keratin. The sulfur in the keratin was mainly removed into the medium in the form of sulfate. Sulfite was also found in the medium. The concentration of sulfite changed relating to keratinase activity, keratin degrading rate, soluable protein and thiol concentration, which indicates sulfite plays important role in the process of keratin degradation. Both enzymatic pathway (degradation by keratinase) and non-enzymatic pathway that is sulfitolysis occurred in the degradation process by streptomycete sp.B221.