Mapping and isolation of large peptide fragments from bovine neurophysins and biosynthetic neurophysin-containing species by high-performance liquid chromatography

A peptide mapping procedure suitable for rapid analysis and peptide recovery was devised for the neurophysins. Tryptic fragments of performic acid-oxidized bovine neurophysins I and II were fractionated by reverse-phase high-performance liquid chromatography using γ-cyanopropyl-bonded columns. Elutions were achieved using a gradient from triethylammonium phosphate buffer to mixtures of this buffer with increasing proportions of acetonitrile. All tryptic fragments, except for dipeptides, were separated. Assignments of eluted peaks to particular authentic neurophysin peptides were achieved by collection of peaks and determination of their amino acid compositions. The use of this peptide mapping procedure to detect subpicomole amounts of neurophysin peptides in cell-free biosynthetic products was demonstrated.