THE SEQUENCE OF PORCINE CHROMOGRANIN A MESSENGER RNA DEMONSTRATES CHROMOGRANIN A CAN SERVE AS THE PRECURSOR FOR THE BIOLOGICALLY ACTIVE HORMONE, PANCREASTATIN

Abstract

Specific oligonucleotide priming of double-stranded DNA has been employed to sequence a porcine chromogranin A adrenomedullary cDNA. Porcine chromogranin A is more than 80% identical to human, bovine, and rat chromogranin A at its deduced N- and C-terminal. A 49-amino acid region of the porcine molecule in 59-71% homologous to corresponding areas of rat, bovine, and human chromogranin A, and identitical to the amino acid sequence of porcine pancreastatin. The sequence is preceded by an arginine at the N-terminus and followed by a GKR sequence at the C-terminus. Thus, porcine chromogranin A can serve as the precursor for pancreastatin, a polypeptide capable of inhibiting insulin release from the endocrine pancreas and acid secretion from parietal cells of the gut.