[A-21-D-Asparagine] sheep insulin, a diastereoisomer of the natural hormone

Abstract

The synthesis and isolation in purified form of [A-D-Asn²¹] sheep insulin is described. For this purpose [D-Asn²¹] A chain S-sulphonate was synthesized by the fragment condensation approach and isolated in a purified form. Conversion of the latter into its thiol form and combination with the S-sulphonated B chain of bovine (sheep) insulin produced the [A-D-Asn²¹] sheep insulin, isolated by chromatography on a carboxymethylcellulose column with an exponential sodium chloride gradient. The [A-D-Asn²¹] insulin shows potencies (I.U. mg^–1) of 8 when assayed by the mouse convulsion method and of 4 by the radioimmunoassay method (cf. 23–25 for the natural hormone).