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Study on the intermediate ions formed by glutathione peroxidase mimic 2,2'‐ditellurobis(2‐deoxy‐β‐cyclodextrin) by electrospray ionization mass spectrometry
Author(s) -
Jiao Aiquan,
Yang Na,
Xu Xueming,
Jin Zhengyu
Publication year - 2012
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.6455
Subject(s) - chemistry , electrospray ionization , catalysis , mass spectrometry , tandem mass spectrometry , hydrogen peroxide , reaction intermediate , electrospray , catalytic cycle , combinatorial chemistry , photochemistry , chromatography , organic chemistry
RATIONALE 2,2'‐Ditellurobis(2‐deoxy‐β‐cyclodextrin) (2‐TeCD) is one of the most well‐known glutathione peroxidase (GPx) mimics. However, because the critical reaction intermediates had not previously been isolated or directly detected due to its short lifetime, the catalytic mechanism of 2‐TeCD is not very clear and further experiments are needed to characterize each of the intermediates in the catalytic cycle. METHODS Using electrospray ionization mass (and tandem) spectrometry (ESI‐MS and ESI‐MS/MS) experiments, the decomposition of hydrogen peroxide at the expense of glutathione (GSH) catalyzed by 2‐TeCD was monitored on‐line. RESULTS The key intermediates were successfully intercepted and structurally characterized for the first time by coupling a microreactor on‐line to the ESI ion source, which permitted the fast screening of intermediates directly from solution. CONCLUSIONS The catalytic mechanism of 2‐TeCD catalysis has been elaborated based on mass spectrometric data and exerted its peroxidase activity via tellurol, tellurenic acid, and tellurosulfide, in analogy with natural GPX. Copyright © 2012 John Wiley & Sons, Ltd.