Post-translational modifications (PTMs) are additional covalent changes to the protein’s amino acids following biosynthesis. Some proteins require PTMs to reach their mature, functional state. These modifications play an important role in enzyme activation, cell signalling, and protein stability, making PTMs an important and interesting aspect of protein research.
Common PTMs include disulphide bridges, phosphorylation, and glycosylation.
This technique is used to characterise disulphide folding pattern, i.e., an analysis of which Cys residues are linked.
Scope of work:
For analysis we require the full theoretical protein sequence, and postulated S-S bridging patterns.
Request Form: Disulphide Bridge Analysis
Identification of phosphorylation sites on protein and peptide samples is achieved through titanium dioxide enrichment of the phosphorylated peptides after digestion. This allows detection of just the phosphorylated peptides from a sample and allows identification of the phosphorylation site.
For phosphorylation detection we use a LC-MS/MS system (5600 Triple-TOF [Sciex]). Our approach is first to perform protein identification by tandem MS (as per our standard service). This enables confirmation of protein identity prior to detection of the phosphorylated peptides.
Request Form: Phosphorylation Detection
We recommend protein bands or spots are of sufficient concentration to be detected by Coomassie G250 staining. Two bands are required to enable the initial protein identification, although less material can be used for that process. Larger amounts of material increase the probability of achieving a successful result.