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Studies of interaction between insulin and glutathione using electrospray ionization mass spectrometry
Author(s) -
Du Yonggang,
Zhang Ningbo,
Cui Meng,
Liu Zhiqiang,
Liu Shuying
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.6248
Subject(s) - chemistry , glutathione , electrospray ionization , mass spectrometry , insulin , fourier transform ion cyclotron resonance , protein mass spectrometry , electrospray , chromatography , tandem mass spectrometry , sample preparation in mass spectrometry , biochemistry , enzyme , medicine
RATIONALE The interaction of glutathione (GSH) with insulin plays an important role in the degradation or regulation of insulin. The characterization of the reaction products of GSH and insulin is very important for a proper understanding of the mechanism of insulin regulation of GSH. METHODS Solutions of insulin and glutathione were incubated under different experimental conditions in vitro . The reaction products were determined by electrospray ionization (ESI) ion trap mass spectrometry combined with Fourier transform ion cyclotron resonance (FTICR) mass spectrometry. RESULTS The multi‐reaction products were identified, including insulin A chain with two intrachain disulfides, insulin B chain with one intrachain disulfides, GSH‐modified insulin, GSH‐modified A chain, GSH‐modified B chain, aggregates of A chain and B chain, and reduced A chain and B chain. The binding site of the B chain with insulin was determined directly by tandem mass spectrometry (MS/MS) without enzyme digestion. It was found that the reaction between GSH and insulin was pH‐, O 2 ‐ and temperature‐dependent. CONCLUSIONS The results provide insight into the interaction between GSH and insulin. It has also been demonstrated that ESI‐MS combined with high‐resolution FTICRMS and MS/MS provides a powerful tool for screening the reactions of proteins and small molecules. Copyright © 2012 John Wiley & Sons, Ltd.