Prosomatostatin is a relatively small biosynthetic precursor which undergoes monobasic and dibasic cleavages to release two functional hormones; i.e. somatostatin-28 and somatostatin-14. Secondary structure motifs such as reverse turns were shown to play an essential role to discriminate between functional cleavage sites and those that are not cleaved. In prosomatostatin, both mono- and dibasic residues are separated by a dodecacapeptide segment (somatostatin-28(1-12) ) that is important in the generation of both somatostatin molecules.

        In the present review article, we will discuss our recent data on differential processing of human prosomatostatin and specifically the role of secondary structure types in proteolytic processing. In teleostean fish, the mature somatostatin-14 and somatostatin-28 peptides are derived from two distinct precursors; i.e anglerfish prosomatostatin I and II, respectively. Particular residues and local secondary structures, responsible for these differences, will be underlined and their correlation with the corresponding proteolytic processing of each prosomatostatin will be emphasized.