Synthesis of a 21-residue fragment of human proinsulin by the polyamide solid phase method

The synthesis of human proinsulin fragment residues 40-60 by a solid phase method based on polydimethylacrylamide is described. Nineteen of the amino-acids were introduced as N alpha-(9-fluorenylmethoxycarbonyl) derivatives; functional side chains were protected as t-butyl ethers and esters. The yield of highly purified 21-residue peptide was 56.5%.