Studies on polypeptides. Part X: Synthesis of 1‐13[10‐Homoarginine, 13‐Leucine] bovine pancreatic ribonuclease by combined solid‐phase and classical methods

Merrifield's solid-phase method was applied to the synthesis of all-L-glutamyl-homoarginylglutaminylhistidylleucine. Azide coupling in solution with all-L-Nα, Nϵ-di-t-butoxycarbonyllysyl-γ-t-butylglutamylthreonylalanylalanylalanyl-Nϵ-benzyloxycarbonyllysylphenylalanine hydrazide, also prepared on a solid support1 , resulted in the N-terminal tridecapeptide sequence of bovine pancreatic ribonuclease in which homoarginine and leucine replace arginine-10 and methionine-13, respectively.