title: C-terminally extended ocytocin and pro-ocytocin: neurophysin peptide converting enzyme in bovine corpus luteum.
abstract: Purified secretory granules from the corpus luteum of super ovulated and fecundated cows, at day 7-8 after the heat period, were used as a source of pro-ocytocin/neurophysin (pro OT/Np) processing enzymes. An endoprotease comparable to the previously described pituitary enzyme both by its catalytic properties and sensitivity to various inhibitors was characterized. This protease cleaves pro OT/Np (1-20) after the basic Lys11Arg12 doublet to release OT Gly10 Lys11 Arg12. Moreover C-terminally extended ocytocin, i.e. OTGlyLys and OTGlyLysArg together with ocytocin were identified in extracts from the corpus luteum. Together these data argue strongly in favor of pro OT/Np processing pathways in which cleavage of the precursor at the Arg12-Ala13 peptide bond is the primary event.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D003338:Corpus Luteum / Q000502:physiology*; D003594:Cytoplasmic Granules / Q000378:metabolism; D005260:Female; D009481:Neurophysins / Q000378:metabolism*; D010121:Oxytocin / Q000378:metabolism*; D010447:Peptide Hydrolases / Q000378:metabolism; D010904:Pituitary Gland, Posterior / Q000201:enzymology; D011498:Protein Precursors / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D013379:Substrate Specificity
chemical_list: D009481:Neurophysins; D011498:Protein Precursors; D010121:Oxytocin; D010447:Peptide Hydrolases