by MALDI MS/MS and LC-ESI MS/MS
In Mass spectrometric Peptide Mapping the protein is cleaved into smaller peptides using a specific protease. The peptides are analyzed by mass spectrometry and the observed peptides correlated to the protein amino acid sequence.
The identified peptides in the peptide map thus confirms the specific amino acid sequences covered by the peptide map, as well as the identity of the protein.
Mass spectrometric peptide mapping is applied to:
- Confirm the identity of a specific protein.
- Detailed characterization of the protein. Such as confirmation of N-terminal and C-terminal peptides, high sequence coverage peptide maps, amino acid substitutions, etc.
- Screening and identification of post translational modifications. E.g. glycosylations, disulfide bonds, N-terminal pyroglutamic acid, methionine and tryptophan oxidation, etc.
Peptide mapping using a single protease will typically give a sequence coverage of 10-90%. By using two or more proteases this coverage can be increased to 95-100%.
Detailed characterization of a protein requires careful investigation of the protein sequence to select the best proteases, and choice of MALDI MS/MS or ESI LC MS/MS to observe the peptides.
Alphalyse also offers standard protein identification peptide mapping through our PICK ‘n POST service.