Organotelluriumbridged cyclodextrin dimers as art

Authors: Aiquan Jiao Na Yang Jinpeng Wang Alhassane Toure Xueming Xu Zhengyu Jin

Publish Date: 2012/03/03

Volume: 74, Issue: 1-4, Pages: 335-341

PDF Link

Abstract

To elucidate the importance of the goodness of fit in complexes between substrates and glutathione peroxidise GPX mimics we examined the decomposition of a variety of structurally distinct hydroperoxides at the expense of glutathione GSH catalyzed by 22′ditellurobis2deoxyγcyclodextrin 2TeγCD and by the corresponding derivatives of βcyclodextrin βCD and αcyclodextrin The good fit of the cumene group into the γCD binding cavity reflected the result of welldefined reaction geometry leading to the most excellent peroxidase activity with high substrate specificity Furthermore the catalytic constant and the combination with the best binding also exhibited the highest regioselectivity in the substrate decomposition Saturation kinetics were observed and the catalytic reaction agreed with a pingpong mechanism in analogy with natural GPX and might exert its thiol peroxidase activity via tellurol tellurenic acid and tellurosulfide The stoichiometry of the inclusion complex was determined to be of 21 hosttoguest The value of stability constant K c for 2TeγCD2/GSH at room temperature was calculated to be 3815 × 104 M−2 which suggested that 2TeγCD had a moderate ability to bind GSH Importantly the proposed mode of the 2TeCD2/GSH complex was the possible important noncovalent interactions between enzymes and substrates in influencing catalysis and bindingWe are grateful to Dr Kim for providing language help Dr ZF Li and CY Ma for their technical assistance and Miss WH Cui and GQ Wang for secretarial assistance This study was supported by National Natural Science Foundation of China No 20976070 Project of Education Ministry No 109080 Nature Science Foundation of Jiangsu Province Nos BK2008003 and BK2009069

Keywords: