GHK-Cu

Research Overview

GHK-Cu serves as a valuable research tool for investigating copper-dependent biological processes and peptide-mediated tissue remodeling in laboratory settings. This tripeptide was first identified in human plasma and subsequently found in multiple tissue types, with naturally occurring levels declining with age. The peptide’s primary biological function relates to copper binding and delivery, but research has revealed extensive additional activities including gene expression regulation, protease modulation, and cellular signaling effects. Research applications have expanded to encompass investigations of wound healing, tissue repair, extracellular matrix remodeling, anti-inflammatory pathways, and age-related tissue changes.

The peptide’s structure (Gly-His-Lys) creates a specific copper-binding motif where Cu²⁺ coordinates primarily through the histidine imidazole nitrogen and glycine amino terminus, forming a stable square planar complex. This coordination chemistry is critical to GHK-Cu’s biological activities, as the copper ion participates in redox reactions, enzyme cofactor functions, and structural roles. Laboratory studies investigate GHK-Cu’s effects on collagen synthesis, matrix metalloproteinase (MMP) activity, antioxidant enzyme expression, inflammatory mediator production, and tissue regeneration processes.

GHK-Cu research demonstrates the peptide’s remarkable diversity of biological activities despite its small size. Effects span from direct biochemical actions (copper delivery, antioxidant activity) to complex cellular responses (gene expression changes, differentiation effects). The peptide exhibits both copper-dependent and potentially copper-independent activities, though the coordinated complex represents the most biologically active form. Studies examine these effects in cell culture systems, tissue explants, and preclinical animal models assessing wound healing, tissue repair, and age-related changes.

Molecular Characteristics

Complete Specifications:

• CAS Registry Number: 49557-75-7 (GHK peptide); 89030-95-5 (GHK-Cu complex)
• Molecular Weight: 340.38 Da (peptide) + 63.55 Da (copper ion)
• Molecular Formula: C₁₄H₂₂N₆O₄ (peptide) + Cu²⁺
• Sequence: Gly-His-Lys (GHK)
• Peptide Classification: Tripeptide-copper complex
• Appearance: Blue to blue-green lyophilized powder (copper complex)
• Solubility: Water, phosphate buffered saline (pH 6.0-7.5)

The peptide’s three-amino acid structure creates a specific copper-binding motif. The N-terminal glycine amino group and histidine imidazole nitrogen serve as primary copper coordination sites, with additional coordination through peptide backbone carbonyl oxygens or lysine terminal amino group completing the square planar geometry around Cu²⁺. The copper complex exhibits characteristic blue color due to d-d electronic transitions. The stability constant for copper binding is approximately 10¹⁶, indicating very high affinity and stable complex formation under physiological conditions. This tight binding enables copper delivery to tissues while preventing free copper toxicity.

Pharmacokinetic and Biochemical Profile

GHK-Cu characterization in preclinical research reveals important properties for experimental design:

Stability and Distribution:

• High copper complex stability (Ka ~10¹⁶)
• Resistant to peptidase degradation when copper-coordinated
• Tissue penetration enhanced by small size and lipophilicity
• Plasma protein binding minimal for free peptide
• Cellular uptake observed in various cell types

Biological Half-Life:

• Plasma half-life: Short as free peptide (minutes to hours)
• Tissue retention: Extended due to cellular uptake and binding
• Copper delivery to cells: Sustained over extended periods
• Biological effects: Persist beyond plasma clearance suggesting intracellular actions

Copper Delivery Function:

• Facilitates copper transport into cells
• Modulates cellular copper distribution
• Activates copper-dependent enzymes
• Regulates copper-responsive gene expression

These characteristics inform research protocol design. The peptide’s small size enables tissue penetration, while copper coordination provides stability and biological activity. Cellular uptake suggests intracellular targets beyond extracellular matrix effects.

Research Applications

Wound Healing and Tissue Repair Research

GHK-Cu serves as a research tool for investigating fundamental tissue repair mechanisms. Laboratory studies examine the peptide’s effects on:

• Collagen Synthesis Studies: Investigation of collagen type I and III production stimulation in fibroblasts
• Wound Closure Research: Analysis of re-epithelialization, contraction, and healing rate in wound models
• Angiogenesis Investigation: Examination of blood vessel formation and vascular network development
• Fibroblast Activation: Studies on fibroblast proliferation, migration, and extracellular matrix production
• Growth Factor Modulation: Research on TGF-β, VEGF, and other growth factor expression regulation

Research protocols typically employ fibroblast cultures, keratinocyte studies, endothelial cell assays, and in vivo wound healing models to characterize tissue repair effects.

Matrix Metalloproteinase Regulation Research

Substantial research focuses on protease modulation investigation:

• MMP Expression Studies: Research on matrix metalloproteinase gene expression and activity regulation
• TIMP Modulation: Investigation of tissue inhibitor of metalloproteinase (TIMP) expression
• Matrix Remodeling Balance: Studies examining protease/anti-protease balance in tissue remodeling
• Collagen Degradation Research: Investigation of excessive collagen breakdown prevention
• Scar Formation Studies: Research on fibrosis and pathological scarring modulation

Laboratory protocols investigate MMP/TIMP regulation using zymography, enzyme activity assays, gene expression analysis, and matrix remodeling models.

Antioxidant and Anti-Inflammatory Research

Laboratory studies investigate GHK-Cu in oxidative stress research:

• Antioxidant Enzyme Regulation: Research on superoxide dismutase (SOD), catalase, and glutathione peroxidase expression
• Reactive Oxygen Species (ROS) Modulation: Studies on oxidative stress reduction and cellular protection
• Anti-Inflammatory Pathways: Investigation of inflammatory cytokine modulation (IL-1, IL-6, TNF-α)
• NF-κB Pathway Research: Studies on inflammatory transcription factor regulation
• Oxidative Damage Protection: Research on lipid peroxidation, protein oxidation, and DNA damage prevention

Experimental models include oxidative stress paradigms, inflammatory cell cultures, and models of inflammation-related tissue damage.

Gene Expression and Cellular Differentiation Studies

Research applications extend to gene regulation investigation:

• Gene Expression Profiling: Studies examining genome-wide transcriptional effects of GHK-Cu
• Stem Cell Research: Investigation of effects on mesenchymal stem cell differentiation
• Cell Proliferation Studies: Research on cell cycle regulation and proliferation modulation
• Differentiation Pathway Research: Investigation of lineage specification and phenotype determination
• Cellular Signaling Studies: Research on intracellular pathways mediating gene expression changes

Laboratory protocols investigate gene expression using microarray, RNA-seq, and targeted gene expression analysis in various cell types.

Age-Related Tissue Changes Research

Emerging research areas include aging investigation:

• Age-Related Decline Studies: Research on GHK-Cu levels decreasing with age and functional consequences
• Skin Aging Research: Investigation of dermal thickness, elasticity, and appearance changes
• Tissue Maintenance Studies: Research on ECM turnover and tissue homeostasis
• Regenerative Capacity Investigation: Studies examining tissue repair capability in aged contexts
• Anti-Aging Mechanisms: Research on cellular and molecular changes during aging that GHK-Cu influences

Research in this area examines GHK-Cu effects in aged cells, senescence models, and aged animal tissues.

Laboratory Handling and Storage Protocols

Lyophilized Powder Storage:

• Store at -20°C to -80°C in original sealed vial
• Protect from light exposure and moisture
• Desiccated storage environment recommended
• Stability data available for 24+ months at -20°C
• Blue-green color indicates copper complex integrity

Reconstitution Guidelines:

• Reconstitute with sterile water, phosphate buffered saline, or appropriate buffer
• pH should be 6.0-7.5 for optimal complex stability
• Add solvent slowly down vial side to minimize foaming
• Gentle swirling motion recommended (avoid vigorous shaking)
• Allow complete dissolution before use (typically 1-2 minutes)
• Solution should exhibit blue-green color indicating intact copper complex

Reconstituted Solution Storage:

• Short-term storage: 4°C for up to 7-10 days
• Long-term storage: -20°C in aliquots to avoid freeze-thaw cycles
• Maintain pH 6.0-7.5 for complex stability
• Avoid extreme pH that may dissociate copper
• Single-use aliquots recommended

Stability Considerations:
GHK-Cu demonstrates good stability as a lyophilized powder. The copper complex is stable across physiological pH range. Avoid strongly acidic conditions (pH <5) or high chelator concentrations that may compete for copper binding. The characteristic blue-green color serves as visual indicator of complex integrity.

Quality Assurance and Analytical Testing

Each GHK-Cu batch undergoes comprehensive analytical characterization:

Purity Analysis:

• High-Performance Liquid Chromatography (HPLC): ≥98% purity
• Analytical method: Reversed-phase HPLC with UV and metal detection
• Verification of peptide and copper complex

Structural Verification:

• Electrospray Ionization Mass Spectrometry (ESI-MS): Confirms molecular weight
• Peptide sequence verification
• Copper content determination: Atomic absorption or ICP-MS
• Copper:peptide stoichiometry: 1:1 molar ratio verification

Contaminant Testing:

• Bacterial endotoxin: <5 EU/mg (LAL method)
• Heavy metals (other than copper): Below detection limits
• Free (uncoordinated) copper: Minimal levels
• Residual solvents within acceptable limits
• Water content: Karl Fischer titration (<8%)

Documentation:

• Certificate of Analysis (COA) provided with each batch
• Copper content and stoichiometry verification
• Third-party analytical verification available upon request
• Batch-specific QC results traceable by lot number

Research Considerations

Experimental Design Factors:

Researchers should consider several factors when designing GHK-Cu experiments:

1. Copper-Dependent Effects: Many activities require copper coordination. Consider comparing GHK-Cu with free GHK or copper alone to distinguish complex-specific effects.

2. Concentration Selection: Physiological plasma concentrations decline from ~200 ng/ml in youth to ~80 ng/ml with age. Research concentrations span nanomolar to micromolar ranges.

3. Media Considerations: Cell culture media containing copper chelators (e.g., high serum) may affect complex stability. Consider copper supplementation or serum-free conditions.

4. pH Sensitivity: Maintain pH 6.0-7.5 for optimal complex stability in solutions.

5. Multi-Mechanistic Actions: GHK-Cu exhibits diverse activities. Design experiments to isolate specific mechanisms of interest.

Mechanism Investigation:

GHK-Cu’s mechanisms are diverse and include:

• Copper delivery to cells and copper-dependent enzyme activation
• Gene expression regulation (hundreds of genes affected)
• TGF-β signaling pathway modulation
• MMP expression regulation via transcriptional mechanisms
• Antioxidant enzyme expression upregulation
• Inflammatory mediator production modulation
• Stem cell differentiation influence
• Direct antioxidant activity through copper redox chemistry

The peptide’s small size belies its extensive biological activities, likely mediated through multiple mechanisms operating in parallel.

Compliance and Safety Information

Regulatory Status:
GHK-Cu is provided as a research chemical for in-vitro laboratory studies and preclinical research only. This product has not been approved by the FDA for human therapeutic use, dietary supplementation, or medical applications.

Intended Use:

• In-vitro cell culture studies
• In-vivo preclinical research in approved animal models
• Laboratory investigation of biological mechanisms
• Academic and institutional research applications

NOT Intended For:

• Human consumption or administration
• Therapeutic treatment or diagnosis
• Dietary supplementation
• Veterinary therapeutic applications without appropriate oversight

Safety Protocols:
Researchers should follow standard laboratory safety practices when handling GHK-Cu:

• Use appropriate personal protective equipment (lab coat, gloves, safety glasses)
• Handle in well-ventilated areas or fume hood
• Follow institutional biosafety guidelines
• Dispose of waste according to local regulations for biological/chemical waste and metal-containing materials
• Consult material safety data sheet (MSDS) for additional safety information

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