Mass spectrometry peptide ladder

Table II. A tabular presentation of the peptide ladder mass spectrometry. The data was obtained from two mixtures. The first mixture contained the individual peptides from the 9 mer to the 18 mer and the second mixture from the 19 mer to the 32 mer.

Mass spectrometry may be used to determine primary sequences. Partial sequential chemical or enzymic degradation of peptides or proteins can yield a mixture of peptides with progressively shorter sequences. For example, consider the following (hypothetical) polypeptide sequence that has been partially digested with a proteolytic enzyme (carboxypeptidase) to yield the following ladder" of fragments ... 

Analysis of the mixture using matrix-assisted desorption ionization mass spectrometry (section 5.3) allows for direct sequence determination from the snccessive mass differences of the peptide ladder. The application of the volatile trifluoroethyl isothiocyanate results in a significant optimization of this procedure and allows for peptide sequencing at the femtomole level (Bartlet-Jones et al., 1994). C-terminal ladder sequencing uses ammonium thiocyanate in acetic anhydride coupled with mass spectrometric analysis of truncated peptides (Thiede et al, 1997). Matrix-assisted desorption ionization instruments with delayed extraction (Brown and Leimon, 1995) allow for the discrimination of aU amino acids, except Leu and He. 

Bartlet-Jones, M., et al. (1994). Peptide Ladder Sequencing by Mass Spectrometry Using a Novel, Volatile Degradation Reagent, Rapid Communications, in Mass Spectrometry 8 737—742. 

---