链霉菌降解角蛋白的生化机制研究  

Study on the Biochemical Mechanism of Degrading Keratins by Streptomyces fradiae

作　　者：黄林[1] 熊智强[1] 蔡华静[1] 郭美锦[1] 涂国全[1] 

机构地区：[1]江西农业大学生物工程系,南昌330045

出　　处：《微生物学通报》2006年第4期36-42,共7页Microbiology China

基　　金：江西省自然科学基金项目(No.0230028)

摘　　要：对弗氏链霉菌S-221变种降解角蛋白的生化机制进行了初步研究。该菌在角蛋白底物作用下诱导产生角蛋白酶。它是一种复合蛋白酶,含有二硫键还原酶和多肽水解酶等多种酶活性组分。硫酸钠、亚硫酸钠和巯基乙醇对角蛋白酶具有强烈的激活作用,其主要表现作用于角蛋白酶中的二硫键还原酶。亚硫酸钠在0·01mol/L浓度下不仅作用于二硫键还原酶,而且还作用于多肽水解酶。硫代硫酸钠对二硫键还原酶有强烈的抑制作用。角蛋白酶降解羽毛角蛋白首先是角蛋白酶中的二硫键还原酶使角蛋白中二硫键裂解产生变性角蛋白,然后变性角蛋白在多肽水解酶的共同作用下逐步水解成多肽、寡肽和游离氨基酸,使角蛋白彻底降解。在角蛋白降解过程中,角蛋白中的硫也随之转化成巯基化合物,H2S和硫酸盐3种含硫化合物存在于降解产物中。The biochemical mechanism of degrading keratins by S.fradiae var S-221 was primarily studied. The compounds （Na2SO4, Na2SO3 and sulfdryl acohol）, which respecitively enhance specific activity of keratinase, activate keratinase intensively and mainly act on the disulfide bonds reductase in the keratinase, Na2SO3 activates intensively both disulfide bonds reductase and polypeptide hydrolytase at 0. 01 mol/L, whereas Na2S2O3 , which acts on the disulfide bonds recluctase, inhibits keratinase. On the condition that substrate, keratins exists, S.fradiae var S-221 is induced to produce exo-keratinase, which is a muhiproteinase, containing disulfide bonds reductase, which is a key enzyme degrading keratins, then, with polypeptidic, hydrolytase, graduately hydrolyzates denatured keratins into polypeptides, oligopeptides and free amino acids, so that keratins have been decomposed completely. Sulfur in the keratins was transferred into snlthydryl compounds, H2S and sulfates in the course of keratinolysine.

关 键 词：弗氏链霉菌 角蛋白酶 生化机制 

分 类 号：Q936[生物学—微生物学]