GHK-Cu
Copper tripeptide-1 · Glycyl-L-histidyl-L-lysine copper(II)
GHK-Cu is the copper(II) complex of the tripeptide glycyl-histidyl-lysine. The blue colour of the solid comes from the coordinated copper ion; the free peptide is colourless.
Analytical specification
| CAS number | 89030-95-5 |
|---|---|
| Molecular formula | C14H22CuN6O4 |
| Average molecular weight | 403.91 g/mol |
| Amino-acid count | 3 |
| Peptide class | copper(II)-chelated tripeptide complex |
| Physical form | Lyophilized powder, characteristic blue |
| Research area | Tissue & matrix research |
| Solubility | Soluble in water; the copper complex is pH sensitive |
| Primary sequence | Gly-His-Lys · Cu(II) |
Reference values from public analytical chemistry. Confirm against the lot Certificate of Analysis before use in an assay.
The copper is the product
GHK-Cu is a coordination complex rather than a peptide alone, and that changes several handling rules.
The tripeptide chelates copper(II) through the N-terminal amine, the deprotonated backbone amide nitrogen between glycine and histidine, and the histidine imidazole — a square-planar geometry typical of copper(II). The lysine side chain remains free.
Because coordination depends on amide deprotonation, the complex is pH-sensitive: below roughly pH 5 it begins to dissociate and release free copper. Chelators strip it — EDTA and similar agents are incompatible. Reducing agents alter it, since copper(II) reduced to copper(I) changes the coordination chemistry entirely.
On a certificate, an ICP-MS elemental screen reporting substantial copper is correct rather than alarming. The useful question is whether copper content matches the expected stoichiometry, which makes it an orthogonal identity check rather than an impurity finding.
The blue colour is diagnostic. Free GHK is colourless; the complex absorbs in the visible region through a d-d transition. White powder in a vial labelled GHK-Cu is a problem visible before the vial is opened.
Available as
Documentation
Certificates of Analysis are published per lot on release. Look up a lot number to retrieve its certificate.