If you have been reading about tripeptide and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2026-07-12. Numbers and descriptions here follow the published literature rather than marketing material.
Aqueous GHK-Cu solutions are less stable than the dry powder. Light, dissolved oxygen and elevated temperature all accelerate loss of the intact complex, and the main observable changes are fading of the blue colour and the appearance of peptide fragments. Acidic conditions protonate the histidine imidazole and weaken copper binding, while strongly alkaline conditions promote hydrolysis of the peptide backbone. Because several degradation routes operate at once, a single shelf-life figure does not describe all storage conditions.
Solid material is typically kept as a lyophilised powder in a sealed, light-protected container at minus 20 degrees Celsius, with desiccant where humidity is high. Working solutions are often prepared fresh, aliquoted and frozen to avoid repeated freeze-thaw cycles. Glassware and buffers are checked for trace metal contamination, since other transition metals can displace copper. Records of lot number, reconstitution date and storage temperature help trace unexpected colour changes. Blue colour itself is not a reliable purity test, because partly degraded solutions can remain visibly coloured.
Identity and purity are normally checked by reversed-phase high-performance liquid chromatography, often coupled to mass spectrometry. The peptide absorbs in the ultraviolet region, and the copper complex also shows a broad visible absorption band that can be followed spectroscopically. Copper content is measured separately, for example by inductively coupled plasma mass spectrometry or atomic absorption spectroscopy, because the peptide assay alone does not confirm how much metal is bound. Purity figures therefore need a stated basis: peptide peak area, copper content, or both.
The sequence carries three residues in the order glycine, histidine, lysine, which places a small, flexible chain around a single metal centre. Compared with larger copper-binding proteins, the complex is compact and its coordination chemistry can be reproduced with synthetic peptide in a laboratory. Published structural work agrees on the nitrogen donor set but differs in the exact geometry assigned under some conditions, so the arrangement is best treated as well characterised in outline rather than fixed in every detail.
GHK-Cu is a coordination complex formed between the tripeptide glycyl-L-histidyl-L-lysine and a copper(II) ion. The peptide was isolated from human plasma in the early 1970s by Loren Pickart, who observed that a plasma fraction from young donors stimulated growth in cultured liver cells. The copper-bound form is abbreviated GHK-Cu, while the metal-free peptide is written simply as GHK. In the research literature the complex also appears as copper tripeptide-1 and as glycyl-histidyl-lysine copper complex.
Copper(II) binds the peptide through four nitrogen donors: the terminal amino group, the imidazole nitrogen of histidine, and two deprotonated amide nitrogens of the peptide backbone. This tetradentate arrangement gives a roughly square-planar geometry, the thermodynamically favoured form near neutral pH. Because the amide nitrogens must lose a proton before they can coordinate, complex formation is strongly pH-dependent, and the fully coordinated species dominates only above mildly acidic conditions. Electronic transitions within the copper d orbital set produce the characteristic blue to violet colour in aqueous solution.
| Property | Value | Notes |
|---|---|---|
| Powder storage | Minus 20 degrees Celsius, dry, dark | Desiccant used where humidity is high |
| Solution storage | Frozen, single-use aliquots | Repeated freeze-thaw cycles increase breakdown |
| Light sensitivity | Loss of intact complex under prolonged light | Amber or opaque containers reduce exposure |
| Copper assay | ICP-MS or atomic absorption spectroscopy | Reports total copper, not the fraction bound to peptide |
| Purity assay | Reversed-phase HPLC with UV or MS detection | States whether purity refers to peptide peaks or to metal content |
The compound was first isolated from human plasma by the biochemist Loren Pickart in 1973. Early work identified it as a factor that altered the behavior of cultured liver cells, and later studies linked it to connective tissue and wound-related processes. Reported plasma concentrations fall markedly between roughly age twenty and age sixty, a pattern that generated interest in copper peptide biology. Whether that decline has functional consequences remains an open question, because differences observed across age groups do not by themselves establish causation. Research interest later expanded into cosmetic and tissue-culture settings.
Mechanistic accounts focus on how the complex delivers copper and how the released peptide interacts with the extracellular matrix. Copper is an essential cofactor for lysyl oxidase and other enzymes involved in collagen and elastin cross-linking, and GHK is one of several peptides able to carry the metal. Reported effects include altered gene expression in fibroblasts and changes in matrix metalloproteinase activity, although many of these findings come from cell culture rather than whole organisms. The relative contribution of the peptide backbone, the copper ion, and downstream copper metabolism is not fully resolved.
GHK-Cu is the copper(II) complex of the tripeptide glycyl-L-histidyl-L-lysine, a short sequence of three amino acids. The peptide was first isolated from human plasma in 1973 during research on factors that influence tissue repair in liver. Its ability to bind copper ions became a central point of interest because the metal changes the peptide's chemistry and its behaviour in laboratory systems. Today the compound appears in cosmetic formulations, cell-culture studies, and biochemistry literature under several names.
The peptide sequence places a histidine in the middle, and this residue dominates metal binding. Copper(II) coordinates through the imidazole nitrogen of histidine and the terminal amino group, forming a stable chelate ring system. Loss of the copper ion leaves the free tripeptide, which has different solubility and reactivity. This structural detail matters because assays that measure only the peptide backbone can miss whether copper is still bound to it.
Several names circulate for the same material, which complicates literature searches. Cosmetic ingredient lists often use copper tripeptide-1, while older biochemistry papers use glycyl-L-histidyl-lysine or its abbreviation GHK. The copper complex is sometimes written as GHK-Cu(II) to make the oxidation state explicit. Terminology is not fully standardized, so matching a compound across sources requires attention to the exact sequence, the counterion, and the stated copper content. Reviews that compare studies must account for these naming differences before drawing conclusions.
Number of amino acid residues: 583 Molecular weight: 66,463 Da (= 66.5 kDa) isoelectric point in water at 25 °C: 4.7 Extinction coefficient of 43,824 M−1cm−1 at 279 nm Dimensions: 140 × 40 × 40 Å (prolate ellipsoid where a = b < c) pH of 1% Solution: 5.2-7 Optical Rotation: [α]259: -61°; [α]264: -63° Stokes Radius (rs): 3.48 nm Sedimentation constant, S20,W × 1013: 4.5 (monomer), 6.7 (dimer) Diffusion constant, D20,W × 10−7 cm2/s: 5.9 Partial specific volume, V20: 0.733 Intrinsic viscosity, η: 0.0413 Frictional ratio, f/f0: 1.30 Refractive index increment (578 nm) × 10−3: 1.90 Optical absorbance, A279 nm1 g/L: 0.667 ε280 = 43.824 mM−1 cm−1 Mean residue rotation, [m']233: 8443 Mean residue ellipticity: 21.1 [θ]209 nm; 20.1 [θ]222 nm Estimated a-helix, %: 54 Estimated b-form, %: 18
=== Munc13/UNC-13 activation === Diacylglycerol has been shown to exert some of its excitatory actions on vesicle release through interactions with the presynaptic priming protein family Munc13 coded by human genes UNC13A and UNC13B. Binding of DAG to the C1 domain of UNC13 increases the fusion competence of synaptic vesicles resulting in potentiated release. Diacylglycerol can be mimicked by the tumor-promoting compounds phorbol esters.
=== EC 1.14.17 With reduced ascorbate as one donor, and incorporation of one atom of oxygen into the other donor === EC 1.14.17.1: dopamine β-monooxygenase EC |1.14.17.2: deleted, now included with EC 1.14.18.1 monophenol monooxygenase EC 1.14.17.3: peptidylglycine monooxygenase EC 1.14.17.4: aminocyclopropanecarboxylate oxidase
Sources: en.wikipedia.org
=== Central nervous system damage === Damage to neurons in the brain or spinal cord can cause prominent muscle atrophy. This can be localized muscle atrophy and weakness or paralysis such as in stroke or spinal cord injury. More widespread damage such as in traumatic brain injury or cerebral palsy can cause generalized muscle atrophy.
1993/2553) Hull and Holderness Community Health National Health Service Trust (Establishment) Order 1993 (S.I. 1993/2554) Kent Ambulance National Health Service Trust (Establishment) Order 1993 (S.I. 1993/2555) Kettering General Hospital National Health Service Trust (Establishment) Order 1993 (S.I. 1993/2556) King's Mill Centre for Health Care Services National Health Service Trust (Establishment) Order 1993 (S.I. 1993/2557) Leicestershire Ambulance and Paramedic Service National Health Service Trust (Establishment) Order 1993 (S.I. 1993/2558) Leicestershire Mental Health Service National Health Service Trust (Establishment) Order 1993 (S.I. 1993/2559) Lincoln Hospitals National Health Service Trust (Establishment) Order 1993 (S.I. 1993/2560) Northampton General Hospital National Health Service Trust (Establishment) Order 1993 (S.I. 1993/2561) Norwich Community Health Partnership National Health Service Trust (Establishment) Order 1993 (S.I. 1993/2562) Nottingham Healthcare National Health Service Trust (Establishment) Order 1993 (S.I. 1993/2563) Oxfordshire Ambulance National Health Service Trust (Establishment) Order 1993 (S.I. 1993/2564) Oxfordshire Community Health National Health Service Trust (Establishment) Order 1993 (S.I. 1993/2565) Oxfordshire Mental Healthcare National Health Service Trust (Establishment) Order 1993 (S.I. 1993/2566) Pilgrim Health National Health Service Trust (Establishment) Order 1993 (S.I. 1993/2567) Plymouth Hospitals National Health Service Trust (Establishment) Order 1993 (S.I.
3 Ca(OH)2 + 6 S → 2 CaS2 + CaS2O3 + 3 H2O where the S2−2 species corresponds to the disulfide anion −S−S− (with a covalent bond between the two sulfur atoms), also present in pyrite (FeS2), a Fe(II) disulfide mineral. They also successfully controlled this reaction to achieve the conversion of elemental sulfur into a quasi-pure solution of calcium thiosulfate.
=== Ribosomes make proteins === In the 1950s, results of labeling experiments in rat liver showed that radioactive amino acids were found to be associated with "microsomes" (later redefined as ribosomes) very rapidly after administration, and before they became widely incorporated into cellular proteins. Ribosomes were first visualized using electron microscopy, and their ribonucleoprotein components were identified by biophysical methods, chiefly sedimentation analysis within ultracentrifuges capable of generating very high accelerations (equivalent to hundreds of thousands times gravity). Polysomes (multiple ribosomes moving along a single mRNA molecule) were identified in the early 1960s, and their study led to an understanding of how ribosomes read the mRNA in a 5′ to 3′ direction, generating proteins as they do so.
Sources: en.wikipedia.org
== Obesity == The British medical journal, Lancet, published a study examining trends in mean body mass index (BMI) for adults in all countries. Obesity was defined as a BMI score greater than 30. Age standardized obesity rates in 2014, broken down by country and gender were extracted from these data. Included were all countries with a population of 10 million or more. Thailand ranked 34 of the top 55 countries (of 200 countries total irrespective of population) (1=most obese). Other ASEAN nations ranked were Malaysia, 32; Indonesia, 41; Philippines, 42; Myanmar, 48; Vietnam, 55. In all ASEAN nations listed, the rate of female obesity exceeded that of males.
Fundamentals of Oncology (1997; co‑editors: Miklós Kásler, István Ember, László Kopper, László Thurzó) Dictionary of Epidemiology (2003; co‑editor: Piroska V. Hajdú) The Health Status of the Hungarian Population at the Turn of the Millennium (2003) Preventive Medicine and Public Health (2006, 2012; first and second editions) Public Health Genomics (2013; co‑editors: Judit Sándor, Angela Brand) Public Health in Budapest (2014; co‑editor: Tamás Szentes) Health Diplomacy (2014; co‑editors: Mihály Kökény, Ilona Kickbusch) Public Health Medicine (2015; co‑editors: István Kárpáti, György Paragh) Preventive Services in Primary Care (2017; co‑editor: Magor Papp) Preventive Medicine and Public Health (third edition, 2023; co‑editors: István Kiss, Edit Paulik, János Sándor, Zoltán Ungvári)
Supelco is the chromatography products branch of Sigma-Aldrich. It provides chromatography columns and related tools for environmental, government, food and beverage, pharmaceutical, biotechnology, medical and chemical laboratories; sample preparation products and chemical reference standards.
Sources: en.wikipedia.org
The colour depends on copper held in a specific coordination environment. When the complex dissociates or the peptide is cleaved, that environment changes and the visible absorption weakens.
Frozen solutions are generally less stable than dry powder, and repeated thawing accelerates breakdown. Storage temperature, concentration and buffer composition all shift the rate, so no single figure applies to every preparation.
Chromatography separates and quantifies peptide species but does not report metal content. A separate elemental measurement is needed to show how much copper is present.
It consists of a three-amino-acid peptide, glycine-histidine-lysine, bound to one copper(II) ion. The peptide supplies four nitrogen donor atoms, and the resulting complex is stable in neutral aqueous solution. The metal-free peptide is usually called GHK.