用硫酸铵盐析, 磷酸盐除果胶和两次 DEA E 纤维素柱层析等方法, 从毛花猕猴桃( Actinidia eriantha Benth .) 无细胞提取液中提纯蛋白酶, 在聚丙烯酰胺凝胶电泳上呈现一条带, 纯酶的活力为 325 U/mg , 比活力提高 89 倍, 总收率约为 37%。 用 SDS 聚丙烯酰胺凝胶电泳测定分子量为 23kD, 用等电聚焦电泳测定等电点为 4.8 。 酶的最适 pH 为 3.8, 最适温度为 43 ℃左右。 纯酶制剂对其底物牛血红蛋白的 Km 值为 5.56 ×10 ^-3 mmol 。 酶的紫外吸收光谱最大值为 278 nm 。 二巯基苏糖醇、巯基乙醇、L-半胱氨酸盐酸盐等还原剂对该酶有明显的激活作用, 而碘乙酸、对氯汞苯甲酸对其有抑制作用, 这表明该酶属于巯基酶类。
 

Pro tease of Actinidia eriantha Benth .w as purified to electrophoretic homogeneity by a combination of ammonium sulfate precipitation, removement of pectin by phosphate, two times chromatog raphy on DEAE cellulose.The specific activity of purified enzyme was 325 U/mg protein, w hich represented as 89-fold purification w ith a 37 % yield. The molecular weight w as estimated to be about 23 kD by the SDS-polyacrylamide gel electrophoresis, and the isoelectric point w as found to be 4 .8 by isoelectric focusing. The optimum pH fo r the enzy me w as 3 .8, optimum temperature w as 43 ℃, and its Km value for bovine hemog lobin w as 5 .56 ×10^-3 mmol .The maximum absorption of UVspectra of the enzyme w as at 278 nm .Some reductants such as DTT, ME, L-cysteine stimulated the enzy me activity, while I-AA, PCMB inhibited activity . It suggested that the enzy me is a thiol pro tease .