Proteins are macromolecular compounds formed by the dehydration condensation of amino acids, which contain both amino-terminus (-NH2, N-terminus) and carboxy-terminus (-COOH, C-terminus). The C-terminus is an important structural and functional site of proteins. Some specific post-translational modifications, such as C-terminus cleavage, affect the structure of proteins and thus their biological functions. Therefore, studying the amino acid species and sequence of the C-terminal of the protein is helpful to reveal the structure and function of the protein.
With the deepening of proteomics research, C-terminal sequencing plays an increasingly important role in protein function research .Especially for protein biopharmaceuticals, C-end sequencing is essential. Several new protein C-terminal sequencing methods have been established with improved sensitivity and reproducibility that can be applied at the proteome level.
C-terminal sequencing method
There are three methods for protein C-terminal sequencing: carboxypeptidase method, chemical method and tandem mass spectrometry. Currently, the more widely used method is tandem mass spectrometry.
The strategy of carboxypeptidase and chemical methods is to obtain the C-terminal amino acids by enzymatic or chemical reagent cleavage, which is combined with liquid chromatography or mass spectrometry techniques for the identification of amino acid species.
The principle of C-terminal sequence determination by tandem mass spectrometry is to digest the protein sample into peptide mixtures, then analyze the peptide mixtures by tandem mass spectrometry and deduce the complete C-terminal amino acid sequence in combination with corresponding software and database.
C-terminal sequencing service
Creative Proteomics uses tandem mass spectrometry for protein C-terminus sequencing. Our efficient and accurate C-terminus sequencing service is based on advanced ESI and MALDI TOF, which can detect blocked and modified protein C-termini, confirm whether the recombinant protein is fully expressed, detect whether the recombinant protein is broken during expression, and whether the C-terminus sequence of the recombinant protein is modified, etc.
Does not require carboxypeptidase digestion and chemical cleavage;
High precision and accurate results.
Suitable for all types of C-terminal sequence detection.
Sample delivery requirements
The purity of the sample for HPLC detection should not be less than 95%.
The protein amount should be at least 50ug and the protein concentration should not be less than 0.5mg/ml.
The sample should be recombinant protein or known sequence protein.