{"id":448,"date":"2026-09-04T12:15:30","date_gmt":"2026-09-04T10:15:30","guid":{"rendered":"https:\/\/reborn-peptides.com\/knowledge\/copper-peptide\/"},"modified":"2026-09-04T12:15:30","modified_gmt":"2026-09-04T10:15:30","slug":"copper-peptide","status":"publish","type":"page","link":"https:\/\/reborn-peptides.com\/en\/knowledge\/copper-peptide\/","title":{"rendered":"Copper Peptide: Copper-Binding Tripeptides in Cell Research"},"content":{"rendered":"

A copper peptide<\/strong> is a short peptide capable of coordinating copper ions. A frequently studied example is GHK, the tripeptide composed of glycine, histidine and lysine. When it binds a copper(II) ion, it forms the GHK-Cu complex. Free GHK and GHK-Cu are therefore two chemically distinguishable species, while copper peptides<\/strong> describes a broader material class. Each published observation must be assigned to the species actually examined.<\/p>\n

The materials discussed are for laboratory research use only. They are not for human or veterinary use. This page describes chemical identity and laboratory findings without transferring them to humans or animals. For context, see what peptides are<\/a> and peptide research basics<\/a>.<\/p>\n

Which species predominates under particular conditions depends measurably on pH and ligand ratio. Equilibrium measurements of GHK and two synthetic analogues found copper complexes with different stoichiometries and stabilities (in vitro; potentiometry, calorimetry, UV-Vis, CD and EPR; PMID 11325542; DOI 10.1016\/S0304-4165(01)00127-1). A pH titration of Cu(II)-GHK found three optical transitions with apparent pK values of 3.6, 9.2 and 11.4 (in vitro; EPR, electron spin echo and pH titration; PMID 6291585; DOI 10.1021\/bi00262a004). A material designation alone consequently does not establish the species present.<\/p>\n

From the tripeptide to the copper(II) complex<\/h2>\n

GHK is the amino-acid sequence Gly-His-Lys, also written gly-his-lys<\/strong>; GHK-Cu is the copper-bound form of that tripeptide. The histidine side chain participates in metal coordination. At neutral pH, the researchers described a mononuclear 1:1 Cu(II)-GHK complex with two to three equatorially coordinating nitrogen atoms; electron spin echo located one of them in the histidyl imidazole ring (in vitro; EPR and electron spin echo; PMID 6291585; DOI 10.1021\/bi00262a004). At higher pH, the structure changed while imidazole binding remained. The full coordination geometry thus depends on the experimental environment.<\/p>\n

Copper-binding peptides<\/strong> add a separate classification level because they extend beyond GHK-Cu. A class-level finding and a finding for one defined complex do not have the same scope.<\/p>\n