Recombinant proteins are often existing as different protein species.
- N-terminal variants
- Lysine clipping (C-terminal variants)
- Internal truncation products
- N-terminal glutamine cyclization (-> Pyro-Glu)
Proteome Factory offers different services to characterize terminal variants such as peptide mapping after directed proteolysis, N- & C-terminal sequencing and intact mass determination.
Further reading:Dick, L. W., Qiu, D., Mahon, D., Adamo, M. and Cheng, K.-C. (2008), C-terminal lysine variants in fully human monoclonal antibodies: Investigation of test methods and possible causes. Biotechnol. Bioeng., 100: 1132–1143. doi: 10.1002/bit.21855