GHK-Cu: The Copper Tripeptide — Discovery, Structure, and Matrix Biology Research
Discovery
The tripeptide glycyl-L-histidyl-L-lysine (GHK) was first identified by Dr. Loren Pickart in 1973 during research at the University of California, San Francisco. Pickart observed that liver tissue from young donors promoted synthesis of fibrinogen in older liver tissue, and isolated GHK as the responsible factor. The subsequent discovery that GHK forms a high-affinity complex with copper(II) ions (GHK-Cu, stability constant log K = 16.44) established it as a naturally occurring metallopeptide.
GHK-Cu is present in human plasma at approximately 200 ng/mL in young adults, with concentrations declining significantly with age—a finding that has driven substantial research interest.
Chemical Structure and Coordination Chemistry
GHK-Cu has a molecular weight of approximately 404 Da (molecular formula: C₁₄H₂₄CuN₆O₄). The copper(II) ion adopts a square-planar coordination geometry, binding through four nitrogen donors:
- The glycine α-amino nitrogen
- The deprotonated amide nitrogen of the Gly-His peptide bond
- The histidine imidazole Nπ nitrogen
- A fourth coordination site occupied by a water molecule or the lysine side-chain amine
This coordination mode has been confirmed by X-ray crystallography and EPR spectroscopy. The peptide appears as a characteristic blue to blue-green lyophilized powder due to the d-d electronic transitions of the copper(II) center.
Documented Biological Activities (In Vitro)
Matrix Metalloproteinase Modulation
Cell culture studies have demonstrated that GHK-Cu modulates the expression of matrix metalloproteinases (MMP-1, MMP-2) and their tissue inhibitors (TIMP-1, TIMP-2). This bidirectional regulation—suppressing excess MMP activity while supporting baseline remodeling—has made GHK-Cu a subject of extensive extracellular matrix research.
Copper-Dependent Enzyme Activity
GHK-Cu serves as a bioavailable copper delivery vehicle for copper-dependent enzymes including:
- Lysyl oxidase (LOX): catalyzes cross-linking of collagen and elastin fibers
- Superoxide dismutase (SOD): key antioxidant metalloenzyme
- Cytochrome c oxidase: terminal electron transport chain complex
Growth Factor Signaling
Published cell culture studies have demonstrated GHK-Cu-mediated modulation of transforming growth factor-beta (TGF-β), vascular endothelial growth factor (VEGF), and fibroblast growth factor (FGF) expression in dermal fibroblast and endothelial cell models.
Gene Expression Profiling
A landmark study using the Broad Institute Connectivity Map database found that GHK-Cu affects the expression of 4,000+ human genes, with significant upregulation of genes involved in ECM production and remodeling, and downregulation of genes associated with inflammatory signaling.
Future Research Outlook
Current research directions include GHK-Cu's potential role in modulating inflammatory gene networks (particularly NF-κB and IL-6 signaling), investigation of its effects on mesenchymal stem cell differentiation in culture, and further characterization of its gene expression modulation profile using modern single-cell RNA-seq technologies.
Available at Crush Research in 50mg and 100mg formats. Every lot independently tested. View Certificates of Analysis.
All products are intended for in vitro and laboratory research use only. Not for human or veterinary use.