N- and C-terminal sequences play an important role in the structure of proteins and polypeptides and can influence their biological function. The N-terminal and C-terminal sequences of biopharmaceuticals are important characteristics for licensing applications and form a key part of the ICH Q6B Guidelines for biotechnological/biological products. The analysis is also necessary to demonstrate comparability and consistency between cGMP batches.

Therefore, structural characterisation of a biopharmaceutical product should include assessment of the N- and C-terminal sequence. This analysis provides confirmation of the consistency and homogeneity between batches for lot release purposes and can reveal if proteins have been truncated or N-terminally blocked. If heterogeneity with respect to terminal amino acid sequences is found, further characterisation analysis should be conducted, and the relative