Protein identification by tandem mass spectroscopy
Genosphere Biotech. provides positive protein identification services using nanoflow LC/MS/MS from one- or two-dimensional SDS-PAGE gels samples. A typical analysis starts with in-gel proteolytic cleavage of the protein(s) sample followed by extraction and mass spectrometric analysis of the resulting peptides. Tandem spectra are further acquired after individual precursor peptide ions are isolated and fragmented thus obtaing peptide sequence information.
- Fig 1. Protein identification by tandem mass spectroscopy. Typical tandem MS experiment showing B-type and Y-type daughter ions
- Click on figure to enlarge
| Catalog No. | Service description |
| F201 | Protein identification: gel - Coomassie |
| F202 | Protein identification: dried gel-Coomassie |
| F204 | Protein identification: 1-3 proteins mixture in solution |
| F207 | High sequence coverage - trypsin |
| F208 | High sequence coverage - 3 proteases |
N-terminal sequencing: Edman’s approach
This procedure involves the sequential (i) chemical modification of the N-terminal residue, through its amino group with phenylisothiocyanate (PITC), (ii) removal of NH2-derivatized amino-acids from the N-terminal, and (iii) reverse phase HPLC analysis with UV detection at 270 nm.
Comparison of the successive elution profile to that of a standard set of adducted amino-acids allows for sequence calls (Fig.1).
- Fig 2. HPLC elution profile of a standard mixture of 19 adducted amino-acids providing standard retention times. Several by-products, indicated by an X, are formed during the Edman degradation process.
- Click on figure to enlarge
