Trypsin liberates an arginine vasopressin-like peptide and neurophysin from a Mr 20,000 putative common precursor.

AUTOR(ES)

Russell, J T

RESUMO

Although the hypothesis that vasopressin and its associated neurophysin are synthesized together in one macromolecular common precursor was put forward more than a decade ago, direct conformation of this hypothesis has been lacking. A [35S]cysteine-labeled putative precursor for vasopressin-related neurophysin (Mr 20,000, pI 6.1) has been isolated from the supraoptic nuclei of rats. This precursor was subjected to limited proteolysis with trypsin which produced a Mr 10,000 protein and peptide products. The former was identified as neurophysin on the basis of its pH-dependent affinity for vasopressin and its behavior in isoelectric focusing systems (pI 4.6-4.8). The tryptic peptides proved to be vasopressin-like because they: (i) were rich in cysteine, (ii) comigrated with vasopressin on gel filtration columns in 6 M guanidine HCl, (iii) bound to a neurophysin-Sepharose affinity column at pH 5.7, and (iv) were recognized by antibodies against vasopressin. These data on the Mr 20,000, pI 6.1 protein represent direct experimental evidence for a candidate for the common precursor of vasopressin and neurophysin. We propose that this common precursor be called "propressophysin."

Documentos Relacionados

• Assembling a jigsaw puzzle with 20,000 parts
• What does a worm want with 20,000 genes?
• Structural organization of the rat gene for the arginine vasopressin-neurophysin precursor.
• Human nonsarcomeric 20,000 Da myosin regulatory light chain cDNA.
• The Mr 80,000 common forms of neurophysin and vasopressin from bovine neurohypophysis have corticotropin- and β-endorphin-like sequences and liberate by proteolysis biologically active corticotropin