Kinetic β‐deuterium isotope effects suggest a covalent mechanism for the protein folding enzyme peptidylprolyl cis/trans‐isomerase

FEBS Letters

Berger, Edith²  Bang, Holger¹  Fischer, Gunter¹ 

[1] Martin-Luther-Universität Halle, Sektion Biowissenschaften, Abteilung Enzymologie, Magdeburg, GDR;Institut für Neurobiologie und Hirnforschung der Akademie der Wissenschaften, Magdeburg, GDR

关键词: cis/trans interconversion;    Prolyl imidic bond;    Deuterium isotope effect;    Prolyl cis/trans-isomerase;    Cyclophilin;    Cyclosporin;    PPIase;    peptidylprolyl cis/trans-isomerase;    β-2H KSIE;    kinetic β-deuterium isotope effect;    CsA;    cyclosporin A;    Glt;    glutaryl;   

DOI  :  10.1016/0014-5793(89)80735-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The cis/trans interconversion of Glt-Ala-Ala-Pro-Phe-4-nitroanilide and Glt-Ala-Gly-Pro-Phe-4-nitroanilide was studied both enzymatically and nonenzymatically by measuring kinetic β-deuterium isotope effects. The hydrogen atom at the α-carbon atom of the Xaa residue within the Xaa-Pro moiety was substituted by deuterium. In the nonenzymatic case the transition state of rotation is reflected by k _H/k _D > 1. When catalysed by 17 kDa PPIase the same bond rotation is characterized by k _H/k _D < 1. This suggests a covalent mechanism of catalysis which involves an approximately tetravalent carbon of the prolyl imidic bond for the transition state of reaction.

【 授权许可】

Unknown