FAB-MS/MS spectrometry in determining the primary structure of .GAMMA.-glutamyl-containing peptides.

Positive fast atom bombardment tandem mass spectrometry (FAB-MS/MS) was applied for peptide sequencing, particularly for determining the gammaglutamyl linkage involved in metal-binding peptides such as Cadystin (yEC)3G = Cadystin A and Cadystin (yEC)2G = Cadystin B (MW771 and 539, respectively).The fragmentation patterns between the natural gammaglutamyl peptide and the synthetic alpha glutamyl one were clearly distinguishable.FAB-MS/MS was proved to be a good method for determining these peptides, since it needed no chemical degradation and only a small amount of the peptide was needed for determination.Cadmium-binding peptides were found as metallothionein-like peptides in the fission yeast, Schizosaccharomyces pombe, by Hayashi and his colleagues in 1981.1}These peptides, Cd-BPl (molecular weight 4000) and Cd-BP2 (MW1800), were induced in the logarithmical growth of the yeast upon exposure to cad-* To whomcorrespondence should be addressed.1651 =Cadystin B have the commonrepeating unit of y-L-Glu-L-Cys ending up with Gly at the C-terminal.This sequence is partly the same as the tripeptide, glutathione.