采用有机溶剂沉淀和柱层析方法,从元宝枫(Ace rtruncatum Bunge)叶片中提取并纯化了叶蛋白酶。该蛋白酶的比活性为 1408. 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 column chromatography. The specific activity of the protease was 1408.04U·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 stableat 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.