Combined Mass Spectrometric Methods for the Characterization of Human Hemoglobin Variants Localized Within αT9 Peptide: Identification of Hb Villeurbanne α89 (FG1) His→Tyr
✍ Scribed by Déon, C.; Promé, J. C.; Promé, D.; Francina, A.; Groff, P.; Kalmes, G.; Galactéros, F.; Wajcman, H.
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 484 KB
- Volume
- 32
- Category
- Article
- ISSN
- 1076-5174
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✦ Synopsis
Mutation-induced amino acid exchanges occurring on the large T9 peptide of the a-chain of human hemoglobin (residues 62-90) are difficult to identify. Despite their high m/z value (around m/z 3000), collision-induced dissociation spectra of liquid secondary ion mass spectrometrically generated protonated aT9 peptides were performed successfully. In parallel electrospray mass spectrometry (MS) was used both to measure the molecular mass of the intact proteins and to determine the number of protonatable sites in the aT9 peptides. Peptide ladder sequencing using carboxypeptidase digestions and analysis of the truncated peptides by matrix-assisted laser desorption ionization time-of-ýight MS conürmed the interpretation. This set of methods allowed the characterization of three hemoglobin variants, with amino acid exchanges located in the aT9 part of the sequence. Two of them, Hb Aztec [ a76(EF5) Met Ç Thr ] and Hb M-Iwate [ a87(F8) His Ç Tyr ] were already known. The third [ a89(FG1) His Ç Tyr ] was novel and named Hb Villeurbanne.