阿拉伯芥超氧歧化酶的研究

Characterization of superoxide dismutase in Arabidopsis

以膠體電泳法分析阿拉伯芥不同生長階段的葉片，莖，花及以paraquat處理過植株之超氧歧化酶（SOD）。並以CN-和H2O2對超氧歧化酶不同程度之抑制作用來鑑定其同功酶。阿拉伯芥不同年齡的葉片及不同器官之SOD同功酶形式相似，都具有Mn-SOD，Fe-SOD和CuZn-SOD，其分子量分別為80KD，50KD，35KD，25 KD及20KD；等電點為pH 3.8, 4.5, 4.8及5.35。CuZn-SOD為阿拉伯芥超氧歧化酶中活性最大之一羣，不同生長階段的葉片，莖，花之活性雖沒有明顯變化；然而paraquat處理過之植株CuZn- SOD III活性卻明顯增加。

Superoxide dismutase (SOD: EC 1.15.1.1) from different plant parts of Arabidopsis and paraquat-treated leaves were characterized using polyacrylamide gel electrophoresis. Five different forms of SOD were identified by their sensitivity to cyanide and hydrogen peroxide. The molecular weight of Mn-SOD, Fe-SOD and CuZn-SODs was estimated to be 80KD, 50KD, 35KD, 25KD, 20KD and 15KD, respectively. A similar pattern of Mn-, Fe- and CuZn-SOD was observed in all plant parts. The pIs of the SODs were determined to be 3.8, 4.5, 4.8 and 5.35 by isoelectric focusing. CuZn-SODs contributed the major activity of total SOD. Only the CuZnSODIII activity showed an apparent increase following the Arabidopsis plants treated with paraquat.