GHK-Cu 50mg

GHK-Cu (glycyl-L-histidyl-L-lysine:copper(II), CAS 49557-75-7) is a naturally occurring copper-binding tripeptide with a molecular formula of C₁₄H₂₄CuN₆O₄ and a molecular weight of 403.93 Da. The peptide was first isolated from human plasma by Pickart and Thaler in 1973, identified through its ability to stimulate hepatocyte proliferation in culture. GHK binds copper(II) ions with high affinity (log K = 16.44 at physiological pH), forming a 1:1 peptide-copper complex that is the biologically active species.

The copper coordination geometry involves the alpha-amino nitrogen of glycine, the deprotonated amide nitrogen of the Gly-His peptide bond, the imidazole nitrogen (N-pi) of the histidine side chain, and a water molecule in a square-planar arrangement. This specific coordination is critical for biological activity — substitution of any of the three amino acid residues or removal of copper abolishes characterized effects in cell-based assays.

GHK-Cu modulates gene expression at a genomic scale. Microarray analysis by Campbell et al. (2012) using the Broad Institute Connectivity Map database identified 4,048 genes whose expression was significantly altered by GHK-Cu treatment. Functional annotation revealed that upregulated genes clustered in extracellular matrix (ECM) remodeling pathways (collagens I, III, V; fibronectin; decorin; versican), integrin signaling cascades, and antioxidant response element (ARE)-regulated genes (superoxide dismutase, glutathione peroxidase, heme oxygenase-1). Downregulated genes clustered in pro-inflammatory pathways (NF-kB targets, IL-6 signaling) and pro-fibrotic mediators (TGF-beta1 downstream targets).

At the protein level, GHK-Cu has been shown to increase collagen synthesis in dermal fibroblast cultures, enhance decorin and glycosaminoglycan production, stimulate metalloproteinase activity (MMP-1, MMP-2) for ECM turnover, and promote VEGF expression for angiogenesis-related signaling.

Supplied as a lyophilized powder for in vitro research applications only. Not for human or veterinary use.

In Vitro Research Applications: GHK-Cu is widely employed in ECM biology and cell signaling research. Primary dermal fibroblast cultures are the most common model system, with standard assays including collagen synthesis quantification (Sircol collagen assay or hydroxyproline assay), glycosaminoglycan production (DMMB assay), and scratch wound migration assays. Endothelial cell models (HUVECs) are used for angiogenesis-related assays including Matrigel tube formation and VEGF expression quantification by RT-qPCR and ELISA. Typical working concentrations range from 0.1 to 10 micromolar.

Signaling Pathway Studies: Key research applications include genome-wide expression profiling (RNA-seq or microarray) to characterize the GHK-Cu transcriptional signature, Western blot analysis of ECM proteins (collagen I, III, fibronectin, decorin), gelatin zymography for MMP-2 and MMP-9 activity quantification, and Nrf2/ARE pathway activation assays. The copper-dependency of observed effects can be verified by parallel experiments with apo-GHK (copper-free peptide) and copper chelators (bathocuproine disulfonate). Integrin-mediated signaling can be characterized by FAK and paxillin phosphorylation assays.

Molecular Characterization: Identity verification is performed via ESI-MS (expected MW 403.93 Da for the copper complex, 340.38 Da for the apo-peptide). Copper content is quantified by inductively coupled plasma mass spectrometry (ICP-MS) or atomic absorption spectroscopy. Purity is assessed by reversed-phase HPLC. Copper coordination geometry can be characterized by electron paramagnetic resonance (EPR) spectroscopy or X-ray absorption spectroscopy (XAS). Binding stoichiometry and affinity are measurable by isothermal titration calorimetry (ITC) or spectrophotometric titration.

References

1. Pickart L, Thaler MM. (1973) Tripeptide in human serum which prolongs survival of normal liver cells and stimulates growth in neoplastic liver. Nat New Biol, 243(124):85-87. PMID: 4512908
2. Campbell JD, et al. (2012) Genomic approaches to identify and investigate genes associated with aging, cancer, and other age-related diseases. Rejuvenation Res, 15(5):483-496. PMID: 23098078
3. Pickart L, Vasquez-Soltero JM, Margolina A. (2015) GHK peptide as a natural modulator of multiple cellular pathways in skin regeneration. Biomed Res Int, 2015:648108. PMID: 26236730