以日本木瓜和皱皮木瓜为原料,用Tris-HCl缓冲液提取过氧化物酶(POD),愈创木酚-H2O2为底物,采用比色法对2种木瓜中的POD酶学性质进行了比较研究。结果显示,皱皮木瓜YATS 115(A)、日本木瓜西府海棠(B)的POD活性的最适温度分别为15℃、30℃,都在30℃以内能较好地保持酶活性。A、B的POD都有2个最适p H值,分别是5和6~6.5,5和5~6,其中B的2个最适p H值差别不明显。A中POD的p H值稳定性范围是5.5~8.5,B的POD在酸性条件下都相对稳定。金属离子对A、B的影响基本相同,Ca2+对2种POD活性都有促进作用。2种POD活性的最佳抑制剂均是SDS,其次为抗坏血酸。

The peroxidase was isolated from Chaenomeles japonica( Thunb.) Lindl and Chaenomeles spiciosa( Sweet) Nakai by Tris-HCl buffer. With guaiacol-H2O2 as substrate,the enzymatic properties of two cultivars were monitored by measuring the absorbance. The results showed that the optimum temperatures for POD activity in YATS115( A) and Chaenomeles Xifu( B) were 15 ℃ and 30 ℃ respectively. The POD of two cultivars could keep stable under 30 ℃. The peroxidases of two cultivars both had two optimum p H. They were respectively 5 and 6 ~ 6. 5,5 and5 ~ 6,but the two optimum p H in B was not obvious. The p H range for stable POD of A was at p H5. 5 ~ 8. 5,while the POD of B could keep stable in acid-stage of p H. Metal ions had the same effects on the POD activity of A and B. Ca2 +activated POD of A and B. The optimum inhibitor of POD activity in both two cultivars was SDS,and then followed by ascorbic acid.