Introduction
The N/C terminal sequence is an important structural and functional part of proteins and polypeptides, and even plays
a decisive role in the biological functions of proteins. The commonly methods for N-terminal sequencing are Edman
degradation and mass spectrometry, and the main methods for protein C-terminal sequencing are carboxypeptidase
method, chemical method and tandem mass spectrometry. However, there are its own advantages and disadvantages about
each of these methods. For example, the sequencing problem of N-terminal blocking (circularization, blocking) is not
solved, and an exact signal of the modified protein cannot given by Edman degradation method. Additionaly, the
purity of the protein or polypeptide is required to be above 95%. On the contrary, Mass Spectrometry locate the
post-translational processing or chemical modification of side chain groups, and make up for the defect that the
traditional Edman degradation method is not suitable for N-terminal blocking, which is complementary to ensure the
smooth progress of N and C terminal sequencing.
Fig. 1. Principles of ISDMALDI MS.
(Ejvind Mort, et al., 2001)
Our Services
It is a regulatory requirement to confirm the sequence of protein and examine the termini for any variation that may
exist. Creative Proteomics, as the world's leading provider of protein sequencing services,
provides you with high-quality one-stop biopharmaceutical N/C-terminal sequencing services with first-class
experimental platforms and mature technical means.
Service Process
To decode the N/C-terminal sequence of biopharmaceuticals, Creative Proteomics' scientists use
the following N/C-terminal sequencing protocol:
Fig. 2. Workflow of our
biopharmaceutical N/C-terminal sequencing service.
Mass Spectrometry-Based N-Terminal Sequencing
Our mass spectrometry-base N-terminal sequencing service is free from interference from N-terminal blocking and
modification sites. Amino acid sequence information is generated from chromatographically separated peptides,
providing much useful structural information as part of such characterization studies.
C-Terminal Sequencing
There is no fully analogous method to definitive C-terminal sequencing of biopharmaceuticals like Edman chemistry. To
assess the C-terminus of biopharmaceutical, Creative Proteomics' scientists offer analysis by
carboxypeptidase hydrolysis in addition to mass spectrometry sequencing.
Carboxypeptidase Hydrolysis Method
First, Our team of experts carry out the kinetic experiment of carboxypeptidase to determine the appropriate enzyme
concentration and reaction time, so that the released amino acids are mainly C-terminal amino acids. According to
the relationship between the amount of released amino acids (moles) and the reaction time, the peptide chain can be
identified C-terminal amino acid sequence. The specific workflow is as follows.
Fig. 3. Workflow of
Carboxypeptidase hydrolysis method.
What Can We Provide?
- Amino Acid Release Analysis
- Structural Analysis of Proteins
- N/C-Terminal Sequence Analysis
- Mass Difference Analysis of Target Peptide Fragments
- N/C-Terminal Modification Site Type Analysis
- Protein Molecular Analysis
Advantages of Our Biopharmaceutical N/C-Terminal Sequencing Service
- High sensitivity: In sequence analysis, mass spectrometry can be used to obtain high sensitivity.
- Sequencing is unaffected by N-terminal modifications such as N-terminal blocking, PEG, and glycosylation.
- High-throughput: The peptide coverage is as high as 100% by using multiple enzymes.
- Fast turnaround time: 5-7 days for detailed technical reports.
- Customized service: We can customize professional solutions for you according to your research plan needs.
Creative Proteomics is a reliable biopharmaceutical partner. Our professional team can provide
customers with comprehensive biopharmaceutical protein N/C-terminal sequence sequencing information, and realize the
analysis of protein advanced structure and modification sites. We will provide you with detailed experimental
procedures and data reports such as the final N/C-terminal sequence information analysis report. Please contact us immediately If you are interested in our services.
References
- Bergman T, Cederlund E, Jornvall H, et al. (2003) C-terminal sequence analysis[D]. Current
protocols in protein science. Chapter 11.
