GHK-Cu vs GHK: the tripeptide and its copper complex
GHK is the tripeptide glycyl-L-histidyl-L-lysine, and GHK-Cu is that tripeptide bound to copper(II).[1],[2]
The FDA substance registry files them as a parent and its copper form, under the names prezatide and prezatide copper.[1],[2]
The comparison here covers recorded identity and the way the peptide holds copper; no biological difference is claimed.
Identity side by side
| Attribute | GHK-Cu | GHK |
|---|---|---|
| Registry name[2],[1] | Prezatide copper | Prezatide |
| Also recorded as[2],[1] | GHK copper; copper tripeptide-1 | GHK; Gly-His-Lys-OH; tripeptide-1 |
| FDA UNII[2],[1] | 6BJQ43T1I9 | 39TG2H631E |
| CAS Registry Number[2],[1] | 89030-95-5 | 49557-75-7 |
| Molecular formula (registry)[2],[1] | C14H22N6O4·Cu | C14H24N6O4 |
| Molecular weight (registry)[2],[1] | 401.91 | 340.38 |
| Registry relationship[2],[1] | Salt/solvate form of prezatide with the cupric cation; active moiety prezatide | Parent substance and active moiety |
How are the two records related?
Both records hold the same three residues in the same sequence: glycine, histidine, lysine.[1],[2]
The copper record lists two components, the tripeptide and a copper ion, and names prezatide as its active moiety.[2]
Its formula carries two fewer hydrogen atoms than the free tripeptide's, and other databases write the complex's formula and charge differently, so formula and mass are only meaningful alongside the record they came from.[2],[1],[3]
How does the tripeptide hold copper?
At neutral pH in solution the tripeptide and copper(II) form a mononuclear 1:1 complex, with a coordinating nitrogen located in the histidine imidazole ring.[4]
X-ray and solution work found the complex dimeric as a solid but monomeric in solution, where copper sits on the terminal amine, an amide nitrogen and the imidazole nitrogen.[5]
When GHK is carried as an N-terminal tag on proteins, crystal structures show copper(II) in a square-pyramidal arrangement completed by residues of neighbouring molecules.[6]
In the presence of human serum albumin, the copper complex has been reported to bind albumin histidine residues, forming two ternary species.[7]
What is not compared here?
The chemistry cited describes how copper binds the peptide and measures no biological difference between the bound and unbound forms.[3]
Free GHK has no compound page in this library, so no study results are recorded for it here.
Limitations
Every binding statement above comes from spectroscopy or crystallography of prepared samples under laboratory conditions.[3]
Which form a given lot contains is a question for identity testing of that lot, not something a registry comparison can answer.
Compound profiles
References
- U.S. FDA Global Substance Registration System (GSRS), Prezatide, UNII 39TG2H631E. UNII 39TG2H631E · CAS 49557-75-7
- U.S. FDA Global Substance Registration System (GSRS), Prezatide copper, UNII 6BJQ43T1I9. UNII 6BJQ43T1I9 · CAS 89030-95-5
- GHK-Cu research profile, PepGenex Science (identity and records, with their sources).
- Freedman JH, Pickart L, Weinstein B, et al. Structure of the glycyl-L-histidyl-L-lysine--copper(II) complex in solution. Biochemistry. 1982;21(19):4540-4544. PMID 6291585 · DOI 10.1021/bi00262a004
- Hureau C, Eury H, Guillot R, et al. X-ray and solution structures of Cu(II) GHK and Cu(II) DAHK complexes: influence on their redox properties. Chemistry. 2011;17(36):10151-10160. PMID 21780203 · DOI 10.1002/chem.201100751
- Mehr A, Henneberg F, Chari A, Görlich D, Huyton T. The copper(II)-binding tripeptide GHK, a valuable crystallization and phasing tag for macromolecular crystallography. Acta Crystallogr D Struct Biol. 2020;76(Pt 12):1222-1232. PMID 33263328 · DOI 10.1107/S2059798320013741 · PMC7709198
- Bossak-Ahmad K, Bal W, Frączyk T, Drew SC. Ternary Cu2+ complexes of human serum albumin and glycyl-l-histidyl-l-lysine. Inorg Chem. 2021;60(22):16927-16931. PMID 34730942 · DOI 10.1021/acs.inorgchem.1c03084