STRUCTURAL STUDY OF ELECTROLYSIS-INDUCED DEGRADATION OF THE GROWTH HORMONE RELEASING PEPTIDE HIS-D-TRP-ALA-TRP-D-PHE-LYS-NH2

摘要

Growth hormone releasing peptide (GHRP, sequence His-D-Trp-Ala-Trp-D-Phe-Lys-NH2) is a synthetic hexapeptide under consideration for transdermal iontophoretic drug delivery. Cyclic voltammetry, controlled-potential electrolysis, HPLC/UV analysis, LC/MS/MS analysis, and EPR spin-trapping studies indicate that the electrolysis-induced oxidative degradation of GHRP is likely to be mediated by electrogenerated oxygen radicals from the electrolysis of water, Within 2 h and up to 2.5 V versus an Ag/AgCl reference electrode, the peptide backbone remains largely intact The chemical modifications are selectively on imidazole (histidine) and indole (tryptophan), Strategies for alleviating the electrolysis-induced degradation of GHRP are proposed. [References: 14]