Study of Highly Selective and Efficient Thiol Derivatization using Selenium Reagents by Mass Spectrometry
Biological thiols are critical physiological components and their detection often involves derivatization. This paper reports a systemic mass spectrometry (MS) investigation of the cleavage of Se-N bond by thiol to form a new Se-S bond, the new selenium chemistry for thiol labeling. Our data shows that the reaction is highly selective, rapid, reversible and efficient. For instance, among twenty amino acids, only cysteine was found to be reactive with Se-N containing reagents and the reaction takes place in seconds. By adding dithiothreitol (DTT), the newly formed Se-S bond of peptides/proteins can be reduced back to free thiol. The high selectivity and excellent reversibility of the reaction provide potential of using this chemistry for selective identification of thiol compounds or enriching and purifying thiol peptides/proteins. In addition, the derivatized thiol peptides have interesting dissociation behavior, which is tunable using different selenium reagents. For example, by introducing an adjacent nucleophilic group into the selenium reagent in the case of using ebselen, the reaction product of ebselen with glutathione (GSH) is easy to lose the selenium tag upon collision-induced dissociation (CID), which is useful to "fish out" those peptides containing free cysteine residues by precursor ion scan. By contrast, the selenium tag of N-(phenylseleno) phthalimide reagent can be stable and survive in CID process, which would be of value in pinpointing thiol location using a top-down proteomic approach. Also, the high conversion yield of the reaction allows the counting of total number of thiol in proteins. We believe that ebselen or N-(phenylseleno) phthalimide as tagging thiol-protein reagents will have important applications in both qualitative and quantitative analysis of different thiol-proteins derived from living cells by MS method.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 988657
- Report Number(s):
- PNNL-SA-72020; 34920; KC0302020; TRN: US201018%%610
- Journal Information:
- Analytical Chemistry, 82(16):6926-6932, Vol. 82, Issue 16
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
AMINO ACIDS
CHEMISTRY
CLEAVAGE
CYSTEINE
DERIVATIZATION
DETECTION
DISSOCIATION
GLUTATHIONE
MASS SPECTROSCOPY
PEPTIDES
PRECURSOR
PROTEINS
RESIDUES
SELENIUM
THIOLS
mass spectrometry
thiol derivatization
selenium reagent
peptide/protein
reaction mechanism
Environmental Molecular Sciences Laboratory