Post-translational modification is an important way to regulate protein function and the key regulatory mechanisms in the phenomenon of life. There are more than 20 common modification types.

Specially, phosphorylation is an important post-translational modification, related closely to signal transduction, cell cycle, growth and development as well as the mechanisms of cancer and many other biological problems. Because protein phosphorylation is dynamic and small in the amount, the phosphorylated peptides are difficult to be ionized in the mass spectrometry, and ion inhibited by non-phosphorylated peptides. We could identify more than 10000 phospholation-sites by using TiO₂ protocol to enrich phosphor-peptides.

We could also measure a Histone modification map targeting many possible modification events/sites in the samples.