This service works best with purified proteins that are mono-methylated at lysine, samples can be sent to us in-gel or in solution. In addition, customer will provide the amino acid sequence or accession number of the target protein.

Identification of mono-methylated lysine sites on a single protein involves virtual digestion of the protein sequence to identify potential peptides containing mono-methylated lysines, followed by MS matching to the virtual digest results and MS/MS fragmentation on matching MS precursors. The presence of a mono-methylated lysine residue is confirmed by the identification of an immonium ion peak at 98 m/z during MS/MS.

Gel Bands/Spots or Liquid samples
Reduction/Alkylation & Trypsin Digestion
MS
Non-methylated peptide peak	Methylated peptide peak
MS/MS
Non-methylated peptide peak	Methylated peptide peak
Database Search for Methylated Site Modification