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.
Guo
Yifei
Y
Department of Chemistry and the MOE Key Laboratory of Modern Analytical Sciences, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China.
Chen
Liqin
L
Yang
Limin
L
Wang
Qiuquan
Q
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