Counting sulfhydryls and disulfide bonds in peptides and proteins using mercurial ions as an MS-tag.
Organic mercurial compounds are the most specific and sensitive reagents for reaction with the sulfhydryl groups (SHs) in peptides and proteins because of the strong mercury-sulfur affinity. Using the monofunctional organic mercury ion RHg(+) as a mass spectrometry (MS)-tag has the advantages of reacting with one sulfhydryl group, offering definite mass shift, and especially stable and characteristic nonradioactive isotopic distribution. Mass spectrometric analysis of derivatized sulfhydryls in peptides/proteins is thus an alternative for precisely counting the number of sulfhydryl groups and disulfide bonds (SS). Here the tags used include monomethylmercury chloride, monoethylmercury chloride, and 4-(hydroxymercuri) benzoic acid. The feasibility of this strategy is demonstrated using HPLC/ESI-MS to count SHs and SS in model peptides/proteins, i.e., glutathione, phytochelatins, lysozyme and beta-lactoglobulin, which contain increasing SHs and various SS linkages.
Department of Chemistry and the MOE Key Laboratory of Modern Analytical Sciences, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China.
Yifei
Y
Guo
Liqin
L
Chen
Limin
L
Yang
Qiuquan
Q
Wang
D002851:Chromatography, High Pressure Liquid; D004220:Disulfides / Q000737:chemistry*; D005034:Ethylmercuric Chloride / Q000737:chemistry; D005978:Glutathione / Q000737:chemistry; D007202:Indicators and Reagents; D008628:Mercury / Q000737:chemistry*; D008767:Methylmercury Compounds / Q000737:chemistry; D009113:Muramidase / Q000737:chemistry; D010455:Peptides / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D013438:Sulfhydryl Compounds / Q000737:chemistry*
D004220:Disulfides; D007202:Indicators and Reagents; D008767:Methylmercury Compounds; D010455:Peptides; D011506:Proteins; D013438:Sulfhydryl Compounds; D009113:Muramidase; D008628:Mercury; D005978:Glutathione; D005034:Ethylmercuric Chloride; C004925:methylmercuric chloride