Abstract: Resin peptides useful in the preparation of peptides having biological activity, and particularly such resin peptides containing Pro--Asp--CH.sub.2 -- or Pro--Asn--CH.sub.2 -- at one end of an amino acid chain, being the resin and Pro, Asp and Asn being the residues of the amino acids proline, aspartic acid and asparagine; and processes for the preparation of such resin peptides.

Abstract: Resin peptides useful in preparing peptides having biological activity, and particularly such resin peptides containing ALA-GLU-CH.sub.2 - R at one end of an amino acid chain, R being the resin and ALA and GLU being the residues of the amino acids alanine and glutamic acid; and processes for the preparation of such resin peptides. Resin peptides including ACTH.sup.1-28 are disclosed which have adrenocorticotropic activity along with processes for their preparation.

Abstract: Resin peptides useful in the preparation of peptides having biological activity, and particularly such resin peptides containing R-CH.sub.2 -Phe-Glu at one end of an amino acid chain, R being the resin and Phe and Glu being the residues of the amino acids phenylalanine and glutamic acid; and processes for the preparation of such resin peptides. Resin peptides are disclosed which contain amino acid chains identical with the amino acid chains of natural peptides having biological activity. Other resin peptides are disclosed which contain amino acid chains in which the amino acid residues differ in kind and sequence from amino acid chains of natural biologically active peptides but from which peptides having biological activity may be derived.