The cDNA structure of the porcine pro-hormone convertase PC2 and the comparative processing by PC1 and PC2 of the N-terminal glycopeptide segment of porcine POMC

AbstractThe complete cDNA structure of the porcine (p) pro-protein and pro-hormone convertase PC2 (pPC2) was obtained from a cDNA library of pituitary neurointermediate lobes mRNA. The deduced amino acid sequence revealed that pPC2 exhibits a 99-97% sequence identity to the human, mouse and rat homologues. The 3′ end of the 2.1 kb cDNA is the least conserved segment. On Northern blots of pars intermedia poly A+ RNA two transcripts of 3 and 5 kb were detected. Molecular analysis of the N-terminal glycopeptide products of porcine pro-opiomelanocortin (pPOMC) co-expressed with vaccinia virus recombinants of PC1 or PC2, revealed that in cells devoid or containing secretary granules both convertases can cleave pPOMC with PC1 releasing the 1–80, 1–107 and 1–148 glycopeptide fragments, and PC2 cleaving pPOMC directly into pPOMC 1–107