Gastrin synthesis

Preprogastrin is synthesized in the endoplasmic reticulum as a 101 amino acid precursor of gastrin. In the Golgi, the signal peptide and carboxyl terminus are cleaved forming a 71 amino acid protein. Gastrin is packaged in secretory granules where further processing occurs to form glycine-extended G-34 and G-17. Final amidation of the carboxyl terminus produces mature G-34 and G-17.