Therapeutic monoclonal antibodies and consistent ends: terminal heterogeneity, detection, and impact on quality

The IgG1 has N-terminal glutamic acid (E) and glutamine (Q). Conversion of E to pyroglutamate (pE) results in no charge change while that of glutamine (Q) to pE results in a loss of amine group. C-terminal lysine is often cleaved off in the bioreactor culture. The terminal heterogeneities can be detected by many analytical methods. A simple CEX profile was shown.