[Total synthesis of human big gastrin I. Revised primary structure (author's transl)]

The synthesis of the tetratriacontapeptide amide corresponding to the revised structure of human big gastrin I is described. The fully protected peptide derivative was obtained by assembly in sequence order of the suitably protected fragments [1--9], [10--14] and [15--34] via the dicyclohexylcarbodiimide/N-hydroxysuccinimide and azide method, respectively. Upon removal of the protecting groups by exposure to trifluoroacetic acid and purification of the resulting crude product by chromatographic methods, human big gastrin I was obtained in satisfactory yields and at a high degree of purity. The identical immunological crossreactivities of natural and synthetic human big gastrin I using anti-porcine big gastrin I antiserum strongly supports the correctness of the newly proposed primary structure of this member of the gastrin family.