具有cGPX活力的含硒抗体酶的酶学及动力学性质研究  

Enzymatic and Kinetic Properties of Selenium-containing Catalytic Antibody with cGPX Activity

作　　者：吴一卉[1] 马雪艳[2] 丁兰[2] 刘兰英[1] 赵大庆[2] 倪嘉缵[2] 

机构地区：[1]吉林大学生命科学学院分子生物学系,长春130023 [2]中国科学院长春应用化学研究所稀土物理与化学开放实验室,长春130022

出　　处：《高等学校化学学报》2000年第11期1621-1626,共6页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金! (批准号 :2 970 10 0 5 );中国科学院基础局重大项目! (批准号 :KJ95 1-A1-5 0 4-0 2 )资助

摘　　要：通过单克隆抗体制备技术得到三株特异结合半抗原 4 ( GSH-S-DNP二苄酯 )的单克隆抗体 HB4 ,HB5和 HB7.抗体经两步化学诱变得到具有细胞谷胱甘肽过氧化物酶 ( c GPX)活性的含硒抗体酶 m HB4 ,m HB5和 m HB7,活力分别为 1 70 ,1 867,32 U/μmol.其中 m HB5的活力是天然兔肝 c GPX的 0 .32倍 ,m 4 A4的1 .51倍 .等离子体 -质谱 ( ICP/MS)测得每分子含硒抗体酶分子中大约存在 2个硒原子 .m HB5的最适 p H为8.6～ 8.8.在 p H值范围为 7.0和 37℃条件下 ,m HB5催化 GSH和 H2 O2 或 t-ROOH反应的二级速率常数为 :k+ 1 ( H2 O2 ) 9.71× 1 0 6 L /( mol· min) ,k+ 1 ( t-ROOH) 5.99× 1 0 5 L/( mol· min) . m HB5使非酶催化反应速率提高了 9.8× 1 0 6和 3.7× 1 0 5倍 .Three selenium containing catalytic antibodies mHB4, mHB5 and mHB7, which acted as mimics of cytosolic glutathione peroxidase(cGPX), were prepared by chemically introducing selenium into monoclonal antibodies HB4, HB5 and HB7. HB4, HB5 and HB7 were raised against a GSH derivative GSH S DNP dibenzyl ester. The cGPX activity of mHB4, mHB5, mHB7 were 170, 1 867, 32 U/μmol, respectively. The cGPX activity of mHB5 was 0.32 fold of natural rabbit liver cGPX and 1.51 fold of m4A4. About two atoms of selenium existed in each of mHB5 molecule determined by inductively coupled plasma/mass spectroscopy(ICP MS). The optimal activity of mHB5 was at between pH 8.4 and 8.8. The reaction catalyzed by mHB5 involved a Ping Pong mechanism. At pH 7.0 and 37 ℃, the apparent second order rate constants for reaction of mHB5 with H 2O 2 and t ROOH were as followed: k +1 (H 2O 2)=9.71×10 6 L/(mol·min), k +1 ( t ROOH)=5.99×10 5 L/(mol·min). Rate accelerations( k cat / K m/ k uncat ) 9.8×10 6 and 3.7×10 5 fold those of the uncatalytic reaction were observed.

关 键 词：单克隆抗体 含硒抗体酶 谷胱甘肽过氧化物酶 

分 类 号：R392.11[医药卫生—免疫学] Q554.6[医药卫生—基础医学]