橡胶种子超氧物歧化酶及其同工酶的研究

橡胶种子提取液对氮蓝四唑(NBT)的光化还原起抑制作用,说明橡胶种子中有超氧物歧化酶(SOD)的存在。以SOD的活性而言,橡胶种子中以胚为最高,而幼苗却以芽为最高。用激素处理的橡胶种子,其SOD活性有所提高,以乙烯利较为明显。经聚丙烯酰胺凝胶电泳的结果表明,橡胶种子粗提取液其SOD具有7～8条同工酶谱带,而且种子各组成部分及幼苗各组成部分,其同工酶的活性及酶谱带数目都有较明显的差异。用氯仿——乙醇及氰化钾对橡胶种子的胚、子叶和外胚乳的处理,证明它们的同工酶谱带中,迁移率较低的五条谱带属于Mn—SOD类型,而迁移率较高的三条谱带属于Cu—ZnSOD类型。用不同pH、不同温度及各种变性剂处理橡胶种子外胚乳提取液,其结果是SOD活性以及同工酶谱带数目都发生明显变化,表明橡胶种子SOD适应于偏碱性,且较耐高温,变性剂能使SOD发生降解甚至活性消失。

A STUDY ON SUPEROXIDE DISMUTASE AND ISOZYME IN RUBBER SEED

The inhibition of crude extract of rubber seed on the photochemical reduction of nitroblue tetrazolium ( NBT ) indicated the presence of superoxide dismutase(SOD) in rubber seed. The SOD activity was the highest either in the embryo of rubber seed or in the bud of seedling. The SOD activity increased when the seed was treated with hormones, especially with ethrel. Results obtained from polyacrylamide gel electrophoresis showed that there were 7 to 8 isozyme bands in the SOD of rubber seed. Significant differences in activity and band number of isozymes were observed between various parts of rubber seed and seedling. The first 5 isozyme bands in embryoes, cotyledons and perisperms were found to be inhibited by chloroform-ethanol, but not affected by potassium cyanide, indicating that they were of the Mn-SOD type, while the 6th to 8th bands, retarded by potassium cyanide, belonged to the Cu-Za SOD type. It was found that both the activity of SOD and the isozyme band number varied obviously as the perisperm extract of rubber seed was treated at different pH and temperatures and with denaturing agents, indicating that SOD in rubber seed was adaptable to alkalinity with better resistance to high temperature. The denaturing agents could degradated SOD or even make it lose its activity.