Study of Highly Selective and Efficient Thiol Derivatization using Selenium Reagents by Mass Spectrometry

Journal Article · Sun Aug 15 04:00:00 EDT 2010 · Analytical Chemistry, 82(16):6926-6932

DOI:https://doi.org/10.1021/ac1011602· OSTI ID:988657

Xu, Kehua; Zhang, Yun W; Tang, Bo; Laskin, Julia; Roach, Patrick J; Chen, Hao

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 Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 988657
• Report Number(s): PNNL-SA-72020; 34920; KC0302020
• Journal Information: Analytical Chemistry, 82(16):6926-6932, Journal Name: Analytical Chemistry, 82(16):6926-6932 Journal Issue: 16 Vol. 82
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
99 GENERAL AND MISCELLANEOUS
AMINO ACIDS
CHEMISTRY
CLEAVAGE
CYSTEINE
DERIVATIZATION
DETECTION
DISSOCIATION
Environmental Molecular Sciences Laboratory
GLUTATHIONE
MASS SPECTROSCOPY
PEPTIDES
PRECURSOR
PROTEINS
RESIDUES
SELENIUM
THIOLS
mass spectrometry
peptide/protein
reaction mechanism
selenium reagent
thiol derivatization