高等学校化学学报 ›› 2000, Vol. 21 ›› Issue (4): 566.

• 论文 • 上一篇    下一篇

具有GPX活力的抗体片段Fv的制备和性质

时成波, 刘俊秋, 罗贵民, 阎岗林   

  1. 吉林大学分子酶学工程教育部重点实验室, 长春 130023
  • 收稿日期:1999-06-26 出版日期:2000-04-24 发布日期:2000-04-24
  • 通讯作者: 罗贵民(1943年出生),男,教授,博士生导师,从事人工酶研究.
  • 基金资助:

    国家自然科学基金(批准号:29671014)

Preparation and Properties of an Antibody Fragment Fv with GPX Activity

SHI Cheng-Bo, LIU Jun-Qiu, LUO Gui-Min, YAN Gang-Lin   

  1. Key Laboratory of Molecular Enzymology and Engineering of State Educational Ministry, Jilin University, Changchun 130023, China
  • Received:1999-06-26 Online:2000-04-24 Published:2000-04-24

摘要: 具有谷胱甘肽(GSH)结合部位的鼠抗体3H4(IgM)经胃蛋白酶水解,产生分子量为25000的抗体Fv片段,用荧光滴定法测定了它与GSH的亲和常数Ka=1.17×107L/mol.该片段经苯甲基磺酰氟活化,再经NaHSe作用,其结合部位的丝氨酸被突变为谷胱甘肽过氧化物酶(GPX)的催化基团硒代半胱氨酸.突变后的Fv片段表现出很高的GPX活性,其活力高达2500U/μmol,称为Fv抗体酶.动力学分析表明,Fv酶的最适温度为55℃,最适pH为7.0,催化机制为乒乓机制,米氏常数分别为:Km(GSH)=4.16×10-3mol/L,Km(H2O2)=2.8×10-4mol/L.

关键词: 谷胱甘肽过氧化物酶, 化学突变, 抗体Fv片段, 抗体酶, 人工酶

Abstract: The mouse McAb3H4 with a glutathione combining site was digested by pepsin to produce an antibody Fv fragment with molecular weight of 25000 . The association constant of Fv to GSHwas found to be 1.17×107 L/mol by using titration of fluorescence quenching. After activation with PMSF, the active serine in the binding site of Fv was mutated to the selenocysteine which is the catalytic group in the natural glutathione peroxidase. The Se containing Fv fragment shows a high GPXcatalytic activity of 2500 U/μmol. Kinetic study shows that the optimum temperature is 55 ℃ and pHis 7.0 . The Fv enzyme has the similar catalytic mechanism to that of the natural GPX. The Km(GSH) of Fv enzyme abzyme is 4.16×10-3 mol/Land Km(H2O2) is 2.8×10-4mol/L.

Key words: Glutathione peroxidase (GPX), Chemical mutation, Antibody Fv fragment, Abzyme, Artificial enzyme

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