For quantification and nuclear magnetic resonance (NMR) experiments, the Proteomics Core peptide synthesis service provides users with purified synthetic peptides, peptide-conjugated immunogens and stable isotope-labeled peptides. Additionally, phosphorylated, biotin-labeled and fluorescently labeled peptides are synthesized in the core.
Peptide lengths can range from four to 60 amino acids. They may comprise the conventional 20 L-amino acids or 20 D-amino acids, or custom synthetic amino acid analogs. Custom synthesis of peptides requiring lengths of more than 60 residues or multiple disulfide bonds can also be synthesized.
The core also offers computer analysis of protein sequences to select peptides for structure-function studies or to design protein-specific peptide immunogens.
- Requirements. Prior to a project being performed, the client must provide the core with the amino acid sequence of the desired peptide, quantity of desired peptide, N-terminal choice of free NH3 or other (such as acetylation, biotinylation or fluorescent label), C-terminal choice of acid or amide, any other modifications required (such as isotopic labeling or a disulfide loop), and the types of studies for which the peptide will be used.
Process. Using an automated peptide synthesizer, the desired amino acid sequence is made with the C-terminal residue attached to one of a variety of resins. Next, the peptide is cleaved from the solid support and side-chain protecting groups are removed by acid hydrolysis.
Crude peptides are then purified by high-performance liquid chromatography (HPLC), and peptide integrity is assessed by mass spectrometry and analytical HPLC. Elemental analysis of peptides used in quantitation studies is highly recommended.
- Considerations. Users should keep in mind that longer sequences (more than 60 residues) are possible, but with considerably lower yield and purity; extremely hydrophobic peptides may be difficult to purify; and cysteine-rich peptides may be difficult to synthesize and purify.
Peptide synthesis fees are based on the amount or scale of peptide requested, the number of preparative HPLC runs needed for a pure product, and the time needed for quality assurance and control of the synthesized peptide. Additional fees are applied for stable isotope amino acids, conjugation reactions and peptide modifications.
For more information or to initiate a service or project request, email the Proteomics Core.