IMG_4883Where do things start and end?

Are you looking to exert a high level of quality control on your natural or recombinant proteins? Ask us to undertake N- and C-terminal sequencing if you need to confirm protein identity and quality, to look for N-terminus, C-terminus and cleavage sites, or even to identify unknown proteins,. In recombinant protein production, C-terminal analysis will also indicate the full-length expression of the gene.

Having had a very early start carrying out these analyses during the emergence of mass spectrometry technology, we offer superior skills and knowledge that have been refined over 15 years.

Excitingly, with MALDI-ISD, we have developed a second analytical method that can directly sequence the N- and C-terminal amino acids of a protein without the need for a proteolytic cleavage. This provides you with an alternative option to techniques such as Edman and its application will depend on your particular circumstances.

N- and C-terminal sequencing is a key part of ICH Q6B. It should be carried out, according to the FDA, to identify the “nature and homogeneity” of the protein.

Technical information

  • N- and C-terminal sequencing can tell you a great deal about proteins and antibodies at any stage of the drug development process. It is also performed to demonstrate consistency and comparability between batches. Here are just some examples of its uses. It can determine the N-terminal blockage or signal peptide cleavage.
  • The level of C-terminal lysine truncation of monoclonal antibodies is a critical quality attribute and therefore needs to be monitored closely. When done by MALDI-ISD, N- and C-terminal sequencing can be used specifically to monitor terminal amino acids for modifications such as glycosylation, disulfide bridging and oxidation.
  • As it’s usually possible to obtain long stretches of amino acids, MALDI-ISD can also be used for de novo sequencing of novel proteins with unknown sequences.
  • Using a suitable enzyme digestion strategy, we can use peptide mapping with LC-ESI-MS/MS to identify and quantify the N- and C-terminal sequence variants.

Your contact for N- and C-terminal Sequencing at Protagen Protein Services GmbH


Dr. Marcus Mreyen

Director Business Development
Our business development team will be happy to assist you with your project.

Phone: +49 (0) 231 9742-6100