Alkaline protease inhibitor: A novel class of antifungal proteins against phytopathogenic fungi

作     者：Vernekar, JV Ghatge, MS Deshpande, VV 

作者机构：Natl Chem Lab Div Biochem Sci Pune 411008 Maharashtra India 

出 版 物：《BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS》 (生物化学与生物物理学研究通讯)

年 卷 期：1999年第262卷第3期

页      面：702-707页

核心收录：

学科分类：0710[理学-生物学] 071010[理学-生物化学与分子生物学] 07[理学] 

基　　金：Bangladesh Council of Scientific and Industrial Research  BCSIR 

主　　题：链格孢属/药物作用 抗菌药/化学 抗菌药/分离和提纯 抗菌药/药理学 抗生素类 抗真菌/化学 抗生素类 抗真菌/分离和提纯 抗生素类 抗真菌/药理学 二聚作用 真菌/药物作用 真菌/酶学 镰刀菌属/药物作用 动力学 微生物敏感性试验 显微镜检查 电子 扫描 肽类 蛋白酶抑制药/化学 蛋白酶抑制药/分离和提纯 蛋白酶抑制药/药理学 丝核菌属/药物作用 丝氨酸内肽酶类/分离和提纯 丝氨酸内肽酶类/代谢 土壤微生物学 链霉菌属/分类 链霉菌属/生理学 链霉菌属/超微结构 木霉属/药物作用 

摘      要：A Streptomyces sp., which produces an alkaline protease inhibitor (API) exhibiting antifungal activity has been isolated from soil. The protein has been purified to homogeneity. The molecular characterization has revealed that it is a dimer (M-r 28 kDa) with five disulphide linkages and has a pI of 3.8. API is a competitive type of inhibitor with a K-i value of 2.5 x 10(-9) M. The inhibitor is stable over a pH range of 6 to 12 and a temperature range of 40 to 95 degrees C. API exhibits antifungal activity (in vitro) against phytopathogenic fungi such as Fusarium, Alternaria, and Rhizoctonia and also against Trichoderma, a saprophytic fungus. The antifungal activity of API appears to be associated with its ability to inhibit the fungal serine alkaline protease(s), which is indispensable for its growth. Retardation of the rate of fungal spore germination, as well as hyphal extention, was observed in the presence of API. Both the protease inhibitory and the antifungal activity were abolished on treatment of API with DTT (5 mM), suggestive of a common site for both the activities. This is the first report on API as a potential biocontrol agent against phytopathogenic fungi. (C) 1999 Academic Press.