Somatostatin is produced as:
Somatostatin tetradecapeptide 14 aa sequence Ala Gly Cys Lys Asn Phe Phe Trp Lys Thr Phe Thr Ser Cys cyclized via disulfide cysteines 3 and 14 functions potent inhibitor growth hormone insulin glucagon secretion, making direct bacterial expression challenging small bioactive peptide inserts membrane disrupts host metabolism undergoes rapid proteolysis cytoplasmic peptidases OmpT. To overcome instability Itakura 1977 expressed synthetic DNA encoding somatostatin fused downstream E. coli beta-galactosidase fragment 590 residues or tryptophan operon leader peptide trpE 190 residues under trp prom
Ref: Itakura et al Science 1977 Somatostatin Fusion Production Landmark; NCBI First Recombinant Peptide Manufacturing Review; Lodish Fusion Protein Expression Chap 9.