锦橙叶片POD动力学研究

以锦橙成熟春梢叶片提取过氧化物酶 (POD) ,分别测定了该酶的最适pH、最适温度及酶促动力学参数Km值和Vmax值 ,比较分析了常见几种POD抑制剂的作用程度。结果表明 :以邻甲氧基酚为底物 ,叶片POD的最适pH为 5 .0 ,最适温度为 32℃ ,Km值为 2 8.0 4mmol/L ,Vmax值为 147.83unit/s·gFW。在所测的 6种抑制剂 (K+、Pb2 +、CN-、Vc、硫脲及L 半胱氨酸 )中 ,CN-,Pb2 +,硫脲和L 半胱氨酸对POD表现出较强的抑制作用 ,K+对POD活性起促进作用。在一定浓度范围内 ,各种抑制剂的作用程度与其浓度具有极显著的相关性

Study on Dynamics of Peroxidase in the Leaf of Orange cv. Jincheng

Peroxidase(POD) in the spring leaf of orange cv.Jincheng(Citrus sinensis Osbeck ) was extracted. The optimum pH, optimum temperature, Km, Vmax and common inhibitors for POD were analyzed. The results showed that the optimum pH and temperature were 5.0 and 32 ℃ respectively, Km and Vmax of POD with guaiacol substrate were 28.04 mmol/L and 147.83 unit/s*gFW respectively. CN-, Pb2+，thiourea and L-cysteine were strong inhibitors, but K+ was an activator for POD in six inhibitors measured. In a proper range of inhibitors concentration, the degrees of inhibition of all the inhibitors have a significant correlation with its concentration.