Tandem mass spectrometric analysis of13C-containing ions from a mixture of homologous peptides differing by one mass unit at a residue
✍ Scribed by Wada, Y.; Hisada, M.; Kaneko, R.; Naoki, H.; Matsuo, T.
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 197 KB
- Volume
- 35
- Category
- Article
- ISSN
- 1076-5174
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✦ Synopsis
Tandem mass spectrometry of a mixture of two peptides that differ from each other by a single mass unit due to mutation is presented. The mutant b-globin of hemoglobin Hoshida is present along with the normal counterpart, and the amino acid substitution of glutamine for glutamic acid is located within tryptic peptide T5 of M r 2057.9. The mass of the mutated peptide is 1 u lower. In the isotopic cluster for the doubly charged ion of the peptide T5, the resolved ion with mass of 1030.0 represents the normal peptide with 93 12 C atoms and the mutated one with 92 12 C and one 13 C atoms. Collision-induced dissociation (CID) of this composite ion identified the mutation by presenting a key fragment derived from the 12 C-only mutant peptide, as reported in a previous study. Similarly, when an ion containing multiple 13 C atoms was selected as a precursor for CID, the mutation could be identified, even in large fragments, by a marked change in the shape of the isotopic cluster for the consecutive product ions. This study demonstrates the merit of selecting a resolved ion rather than the whole isotopic cluster as a precursor in the CID measurements of large peptides or proteins for characterizing heterozygous mutations.