We use solid phase synthesis using Fmoc chemistry with the synthesis starting at the C-terminal end of the peptide and ending at the N-terminus.
When the peptide chain is complete, it is cleaved from the solid-phase resin with acid, a process that also removes the amino acid side chain protections. After removal of the acid, the peptide is ready for purification as required, then quality control (QC) by HPLC and mass spectrometry before being freeze dried, packaged and dispatched.
We offer a range of purity options from unpuriﬁed peptides through to peptide purities of 80-95% and 95-98%. The purity of our puriﬁed peptides is determined by reverse phase HPLC using either C-18 RP Vydac/Ace or Chromolith columns.
|| Use (suitability)
||For large numbers of screening grade peptides.
||NMR studies, X-ray crystallography analysis and for peptides used as enzyme substrates or for mass spec standards.
Impurities arise from non-target components such as truncated sequences of the target peptide, the peptide with protecting groups still intact, or material used in the cleavage process.
Reverse phase chromatography will remove all the reagents used in the cleavage process.
For analysis of HPLC output, a wavelength of 215nm is used as this is the optimum for the detection of the peptide bond and hence detects all peptide species present. The purity value obtained by this method does not include any water and triﬂuoroacetate salt which will be present in the dried material. All puriﬁed peptides are supplied with HPLC and MS traces. At AltaBioscience we make extensive use of capping during synthesis, so deletion peptides are very rare.