Western Analytical Products Crude Synthetic Phosphopeptide 204CT0503

"Crude Synthetic Phosphopeptide: Numerous failure sequences may not be separated by reversed-phase, but the below chromatogram demonstrates the PolyCAT A, when using an acetic acid gradient, will yield a purified target peptide, with remarkable selectivity, superior to Reversed Phase. The sample was the main fraction collected from reversed-phase step. The product was purified satisfactorily at the cation exchange step. Selectivity is remarkable; deletion of a Thr- residue sufficed to afford nearly baseline resolution from the main product. The elution order was as expected in some cases; Loss of -PO4 or Ser(PO4) would decrease electrostatic repulsion and increase retention time, while loss of two Arg- residues decreased retention. However, the loss of all three Arg- Residues had little effect on retention, while loss of a single Arg- actually increased retention. The indicated deletions were identified by ES-MS. Again , one cannot specify which particular residue is missing if there is more than one possibility."