Biosynthesis of neurohypophyseal polypeptides: The order of peptide components in Pro-pressophysin and Pro-oxyphysin

Abstract

Analyses of the pI 5.6 and 6.1 forms of Pro-pressophysin (Pro-PP), and pI 5.1 and 5.4 forms of Pro-oxyphysin (Pro-OP), indicate that all these forms contain both the appropriate nonapeptide hormone (oxytocin or vasopressin) and neurophysin moieties. In addition both forms of Pro-PP contain the glycopeptide adduct characteristic of this prohormone. Cyanogen bromide cleavages of the precursors indicate the nonapeptide hormones are present at the NH 2-terminus of the prohormones, and the glycopeptide moiety in Pro-PP at the COOH-terminus.