元宝枫蛋白酶的分离纯化及其生化性质

Isolation and biochemical properties of a protease from Acer truncatum Bunge

采用有机溶剂沉淀和柱层析方法,从元宝枫(AcertruncatumBunge)叶片中提取并纯化了叶蛋白酶。该蛋白酶的比活性为 1 408. 04U·mg-1,纯化倍数 50. 77。以酪蛋白为底物时,该蛋白酶最适pH 7. 5,最适温度 60℃;该蛋白酶在pH5. 0~pH10. 0范围内以及在 60℃以下较为稳定。该酶的活力能被半胱氨酸和EDTA激活,但受HgCl2抑制,具有巯基蛋白酶的特性。

A protease was extracted and purified from the fresh leaves of Acer truncatum Bunge by means of Sephadex A-50,Sephadex G-200 columnchromatography.The specific activity of the protease was 1 408.04 U·mg^(-1), the purification times was 50.77. The optimal pH value of the protease taking casein as a substrate was about pH 7.5,and the optimal temperature 60℃. It was relatively stable at the ranging from pH 5.0 to pH 10.0 and at the temperature below 60℃.The protease has the properties of mercaptoproteinase, it could be activated by cysteine and EDTA, but inhibited by HgCl_2).