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Poster Presentations
Day 4, June 25（Wed.）
Room P (Maesato East, Foyer, Ocean Wing)
- 4P-AM-39
Development and Application of Cysteine-specific modification for LC-MS analysis
(1Sch. Sci., Kitasato Univ., 2Sch. Allied Health Sci., Kitasato Univ., 3Cent. Disease Proteomics, Sch. Sci., Kitasato Univ.)
oArisa Suto1, Yoshihiro Ishikawa1, Toshihide Matsumoto2, Yoshio Kodera1,3, Takashi Matsui1,3
The alkylation of thiol groups for cysteine (Cys) residues is a critical step in liquid chromatography–mass spectrometry (LC-MS) analysis. In general, to prevent oxidation during experimental steps, halide compounds such as 2-iodoacetamide (IAA) are used as the alkylation reagents. However, these halide reagents often cause side reactions at the N-terminus and other amino acids, thus complicating peptide identification and quantification using LC-MS. Dimethyl sulfoxide (DMSO) is known to promote the disulfide-bond formation, so we overcome this problem using disulfide-bond formation with 2-mercaptoethanol (2-ME) by DMSO. In the presence of DMSO, we found that the 2-ME adduction to Cys residue in proteins was promoted in a DMSO concentration-dependent manner, and the identification of peptides was improved accompanied by significantly reducing modifications to other amino acids compared to those of the conventional methods. Here, we discuss the results of optimizing the conditions for the 2-ME adduction and demonstrate this method's application in various biochemical fields.