菠菜中不同等电点的乙醇酸氧化酶的提取和特性  

PURIFICATION OF GLYCOLATE OXIDASE WITH DIFFERENT ISOELECTRIC POINTS FROM SPINACIA OLERACEA

作　　者：杨净[1] 徐杰[1] 董宇亮[1] 郭晋雅[1] 曾秋莲[1] 陆满芳[1] 

机构地区：[1]华南师范大学生命科学学院广东省植物发育生物工程重点实验室,广东广州510631

出　　处：《华南师范大学学报（自然科学版）》2005年第4期91-98,共8页Journal of South China Normal University(Natural Science Edition)

基　　金：国家自然科学基金资助项目(39800009);广东省自然科学基金资助项目(021105)

摘　　要：从不同批次的菠菜绿叶中可纯化出5种不同活性和等电点(pI)的乙醇酸氧化酶(GO).SDS-PAGE表明它们均有40 kD亚基,它们的比活会随蛋白浓度的增加而上升.第一种GO的pI<8.3,比活为0.47 U/mg,PAGE测定其全酶相对分子量(M r)为280 kD,280 kD较稳定.第二种GO的pI<8.3,但比活为3.44 U/mg,PAGE测定其M r为560 kD,但很快解聚为280 kD.解释了前人报告GO的M r大多为280 kD.第三种GO的pI≈8.3,比活为8.4 U/mg,放置后pI会下降至<8.3,此时用PAGE测出其M r为560 kD.第四种GO的pI>8.3,比活为27.8 U/mg,放置pI也会下降为8.3.第五种GO的pI>10.2,活性高达113 U/mg,放置后其pI也会下降至<8.3,由于GO的pI会下降,暗示低pI的GO可能并不存在于植物体内,而是实验中的娇作物.Five kinds of glycolate oxidase （GO） with different pls and specific activities were purified from green leaves of Spinacia oleracea. All of them contained 40 kD subunit, their specific activities increased as protein concentration. One kind of GO displayed a specific activity of 0.47 U/mg, Mr of 280 kD, and a low pI （ 〈 8.3） assayed by PAGE. The second kind of GO had a pI 〈 8.3, a specific activity of 3.44 U/mg and a Mr of 560 kD. This GO was unstable and dissociate a product with Mr of 280 kD. Among them, GO with 280 kD was stable that explained 280 kD was always reported as the Mr of GO previously. The third kind of GO revealed a specific activity of 8.4 U/mg and a pI about 8.3. This GO was labile and produced an artifact with pI 〈 8.3 and Mr of 560 kD after storage. The fourth kind of GO had a pI greater than 8. 3 and a specific activity of 27.8 U/mg. Its pI also fell to about 8.3. The fifth kind of GO revealed a pI greater than 10.2 and a specific activity of 113 U/mg, its pI also decreased to the value lower than 8.3. In view of the decrease of pls after storage, it was most likely that not all of GO existed in plant indeed, some might be the artifact during the experiment, in despite of about ten kinds of GO with different pls were reported previously.

关 键 词：乙醇酸氧化酶 纯化 PI MR 菠菜 

分 类 号：Q55[生物学—生物化学] Q503