Protein and Peptide Sequencing

The Protein and Peptide Sequencing Facility provides various services for protein characterization and identification. The Facility offers N-terminal sequencing using an automated Edman degradation chemistry capillary sequencer that can generate sequences with less than 1 picomole of starting material. N-terminal sequences are obtained after performing repetitive cycles of Edman degradation chemistry followed by detection of the stable phenylthiohydantoin (PTH) derivatized amino acid residues using an on-line capillary HPLC. The amino acid sequence assignment is determined by comparing the elution time of each amino acid with PTH-amino acid standards.

Since almost 75% of eukaryotic proteins are N-terminally blocked (acetyl, pyroglutamate, formyl etc.), there is the possibility that a N-terminal sequence cannot be obtained. In such cases, the Facility can perform "in gel" protein digests or chemical cleavage (e.g. CNBr) followed by peptide separation on HPLC systems in order to obtain internal protein sequence analysis. Support with sample preparation for protein sequencing and peptides separation is also offered.