Human Proinsulin, VII. Synthesis of Two Protected Peptides Corresponding to the Sequences 1—45 and 46—86 of the Prohormone

Abstract
The synthesis of 2 protected large peptides 1-45, and 46-86 covering the entire amino acid sequence of human proinsulin is described. Peptide 1-45, was synthesized from 2 intermediate fragments 1-23 and 24-45 and purified by countercurrent distribution in dimethylformamide system (K = 0.5). Peptide 46-86 was synthesized from 2 intermediate fragments 46-70 and 71-86 and purified by countercurrent distribution in 2 solvent systems, the dimethylformamide system (K = 0.06), and the toluene system (K = 0.16).