The primary structure of porcine glicentin has been established. The molecule consists of 69 amino acid residues and has a molecular weight of 8128. The sequence of glicentin 1-30 represents the glicentin-related pancreatic peptide (GRPP) previously isolated from porcine pancreas. The sequence 33-61 represents the full sequence of glucagon and the sequence 64-69 is a C-terminal hexapeptide. These three sequences, GRPP, glucagon and the hexapeptide are linked by two Lys-Arg pairs which probably represent the sites for post-synthetic enzymatic cleavages. Glicentin thus fulfils the structural requirements for being proglucagon.