(A14-phenylalanine)insulin: a new synthetic analogue.

An analogue of porcine insulin which differs from the native molecule in that the amino acid residue A14-tyrosine is replaced by phenylalanine has been synthesized. The [PheA14]A chain was synthesized by the fragment condensation method and purified as tetra-S-sulfonate by ion-exchange chromatography on DEAE-cellulose at pH 5.6. Conversion of the tetra-S-sulfonate A chain to the sulfhydryl form and combination with native porcine sulfhydryl B chain gave the [PheA14]insulin, which was purified by gel filtration and ion-exchange chromatography on DEAE-cellulose. The biological activity of this analogue was 96 +/- 6% as measured by the rat epididymal adipocytes. This shows that A14-tyrosine is not essential for the biological activity of the hormone.