Phosphorylation is an important covalent post-translational modification (PTM) in cell signaling pathways. This modification is a reversible process, and is catalyzed by protein kinases. Study showed that over 30% of eukaryotic proteins are subject to phosphorylation. Phosphorylation modification has mainly two regulatory mechanisms for the target proteins: (1) phosphorylation may cause a conformational change in the structure of modified proteins, such as enzymes and receptors, turning "on" or "off" the function. (2) phosphorylation changes the proteins' affinity to their effector, by doing so, phosphorylated proteins can recruit or release their downstream effectors. Hence, it is conceivable that phosphorylation modification regulates a broad range of biological activities, such as cell growth, cell metabolism, cell division, and so on.
Phosphorylation may occur on serine, threonine, tyrosine, and histidine residues in eukaryotic organisms. Among these four types of phosphorylation, tyrosine phosphorylation is most rare, but very crucial. The most famous tyrosine kinase receptor is in the very upstream of the MAPK pathway, and regulates Ras and other kinase, initiating the phosphorylation cascade.
Creative Proteomics has established a highly sensitive HPLC-MS/MS pipeline that can analyze multiple kinds of phosphorylation in both eukaryotic and prokaryotic organisms. In addition, we have optimized our protocol, enabling more fast and sensitive site mapping service for histidine and tyrosine phosphorylation.
Workflow of our Phosphorylation analysis service:
- In gel or in solution digestion of proteins (depends on type of samples you send us)
- Concentration of phosphor-peptides (optional; depends on the abundance of phosphor-peptide)
- HPLC separation, followed by MALDI-TOF MS/MS analysis
- Mass spectrometry data interpretation
For the sample requirements, or more detailed information on our phosphorylation sites identification service, you may send us free inquiry, and our specialists are most willing to discuss with you about your project.