南瓜籽中一种抗真菌蛋白的提取及抗菌活性研究

Isolation and Characterization of a Novel Antifungal Protein from Pumpkin Seeds

裸仁南瓜籽经破碎,磷酸缓冲液4℃浸提,硫酸铵沉淀,上清液透析,SP-Sepharose FF阳离子交换层析,Sephadex G-75凝胶层析柱,冻干等步骤纯化得到一种新的抗真菌蛋白,命名为Pw-1,并对其抗菌活性进行初步鉴定。SDS-PAGE分析显示Pw-1蛋白的分子质量约为14.8 ku。抗菌活性鉴定表明,该蛋白对黄瓜枯萎病菌、大豆灰斑病菌和链格孢霉菌3株真菌具有显著的生长抑制活性,并呈现出剂量依赖的特征,IC50值分别为16.64、20.91和21.22μmol/L。加入胰蛋白酶后Pw-1蛋白的抗菌活性消失,表现出蛋白类物质所具有的对于蛋白酶的敏感性。

A novel antifungal The purification procedure consists protein is measured to be isolated from of extraction with phosphoric acid buffer dialysis, SP-Sepharose FF column, Sephadex G-75 column, freeze pumpkin seeds and designated Pw-1. at 4°C, ammonium sulfate precipitation, drying and other processes. Partial character-ization and antifungal activity are assayed in the paper. The molecular mass of the purified Pw-1 was determined as 14.8 ku by SDS-PAGE. The protein exhibited antifungal activity to the Fusarium oxysporum, Cercospora sojina Ha-ra, and Alternaria alternata in a dose-dependent with IC50 values of 16.64, 20.91, and 21.22 μmol/L respective-ly. The antifungal activity of Pw-I protein disappeared after trypsin addition, showing the protease sensitivity of pro-tein.