The short version of copper chelate fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-12-14. Anything still debated is marked as such rather than presented as settled.
GHK-Cu is a coordination complex formed between the tripeptide glycyl-L-histidyl-L-lysine and a copper(II) ion. The peptide backbone consists of glycine, histidine, and lysine joined in that order. Copper is held through the imidazole nitrogen of histidine and the alpha-amino group at the N-terminus, which together produce a square-planar arrangement around the metal center. The solid appears blue to violet, a color that originates from d-d electronic transitions within the copper coordination sphere. The complex is indexed under CAS number 89030-95-5.
The sequence now called GHK was first reported in the early 1970s after isolation from human plasma, where it was noted to influence liver cell behavior in laboratory preparations. Later work described a copper-binding form and its activity in fibroblast and wound-model experiments. Review articles frequently group the substance with other copper peptides. Concentrations in blood appear to fall with age in several small surveys, although the reason for this trend is not settled. Whether such a decline carries functional consequences remains an open question.
The copper-binding activity of this sequence was described in the 1970s during studies of liver tissue and plasma factors. Early work identified the peptide as a component that influenced copper uptake by cells and that appeared in wound fluid. Later investigations examined its presence across species, reporting the same chain in human and animal samples. A decline in measured concentration with age became a recurring observation, although the underlying causes remain incompletely characterised.
Published studies describe the complex in several research contexts, including collagen synthesis, antioxidant behaviour, and wound repair models. Much of this work is conducted in cultured cells or in small animal systems, and the findings are frequently cited in reviews of copper peptides. Direct clinical evidence in humans is comparatively limited, and reported outcomes vary with formulation and study design. Whether free chain or metal-bound form was used is not always stated, a point that complicates comparison between reports.
GHK-Cu is a coordination complex formed between the peptide glycyl-L-histidyl-L-lysine and a copper(II) ion. The unbound chain, abbreviated GHK, consists of three amino acids and occurs naturally in human plasma, saliva, and urine. Binding of the metal is mediated mainly by the imidazole nitrogen of the histidine residue together with backbone amides, producing a stable chelate. Ingredient nomenclature often lists the same substance as copper tripeptide-1. Its charge and solubility behaviour differ from those of the metal-free chain.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Copper(II) peptide complex | Peptide chain coordinated to a single metal ion |
| CAS number | 89030-95-5 | Indexed for the peptide-copper complex |
| Molecular formula | C14H22CuN6O4 | Approximate formula for a one-to-one complex |
| Appearance | Blue to violet solid | Color from copper d-d transitions |
| Solubility class | Freely soluble in water | Also dispersible in some polar solvents |
Solid GHK-Cu appears as a blue to blue-violet powder, and the colour is a direct consequence of copper coordination. The complex dissolves readily in water and in many polar solvents, while the free peptide behaves differently. Solubility in nonpolar media is low, which limits its use in oil-based systems. Solutions are typically prepared fresh because the dissolved form is more exposed to hydrolysis and to loss of the metal ion than the dry powder. Working concentrations are usually low, and preparation notes often specify the solvent and the order of addition.
Dry material is typically held at low temperature, often around minus twenty degrees Celsius, and protected from moisture and light. Copper complexes can release their metal ion under acidic conditions or in the presence of competing chelators. Hydrolysis of the peptide backbone is a slower but real pathway, and the histidine residue is susceptible to oxidation over long periods. Stability statements therefore depend on formulation, pH, and container, and they should be read as conditional rather than absolute.
Identity and purity are usually assessed with reversed-phase high-performance liquid chromatography, often paired with mass spectrometry. Copper content is measured separately by techniques such as inductively coupled plasma mass spectrometry or atomic absorption. Amino acid analysis confirms the peptide sequence after hydrolysis. Because the metal and the peptide can be quantified independently, a complete certificate of analysis normally reports both values rather than a single purity figure. This separation of measurements is important when comparing suppliers.
Characterizing GHK-Cu requires methods that distinguish the intact complex from free peptide and unbound copper. UV-visible absorption around 600 nm provides a rapid check for copper coordination, while circular dichroism reports on peptide secondary structure. Mass spectrometry confirms the peptide mass and can detect copper adducts under carefully controlled conditions. Electron paramagnetic resonance is particularly informative for Cu(II) because it reveals the ligand field symmetry. No single technique fully defines the complex, so laboratories combine orthogonal methods.
Stability of GHK-Cu in solution depends on pH, temperature, buffer composition, and oxygen exposure. The copper center can undergo reduction or dissociation, especially in the presence of strong metal chelators such as EDTA. Aqueous solutions are often prepared fresh or stored frozen to limit degradation. Lyophilized solid is more stable than liquid formulations, but it can absorb moisture and should be kept dry. Light exposure may also affect copper complexes, though the effect is often modest.
Purity assessment typically involves high-performance liquid chromatography for the peptide and atomic spectroscopy for copper content. The ratio of copper to peptide is a key quality parameter; a value near one indicates proper stoichiometry. Impurities can include free peptide, copper salts, and truncated sequences from synthesis. Because the complex is dynamic, sample preparation and mobile-phase conditions can shift the observed species. Reported purity values therefore depend on the analytical method and should be interpreted with that context.
GHK-Cu is a coordination complex formed between the tripeptide glycyl-L-histidyl-lysine and a copper(II) ion. The peptide sequence is conventionally written as Gly-His-Lys, abbreviated GHK. Copper binds through the imidazole nitrogen of histidine, the alpha-amino group, and a deprotonated amide nitrogen, producing a square-planar geometry. The complex carries a net positive charge near physiological pH and is intensely blue in aqueous solution. The metal-free peptide is often written simply as GHK, while the copper-bound form is written GHK-Cu.
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.
Identity and purity are established with a combination of chromatographic and spectroscopic techniques. Reversed-phase high-performance liquid chromatography separates the intact complex from peptide fragments and free copper, and the elution profile yields a purity estimate. Mass spectrometry gives the mass of the intact species and exposes degradation products. Ultraviolet-visible spectroscopy displays a broad absorption band in the visible region that is characteristic of the copper center. Nuclear magnetic resonance is less informative here, because the paramagnetic metal broadens signals and complicates spectral interpretation.
Copper content is measured separately, since a peptide assay alone does not report the metal-to-peptide ratio. Elemental techniques such as inductively coupled plasma optical emission spectroscopy quantify copper after acid digestion of the sample. The result is compared with the theoretical value for a one-to-one complex, and a shortfall indicates free peptide or partial dissociation. Suppliers differ in how they state purity, as some quote peptide content and others quote the whole complex. A defined stoichiometry therefore requires both a peptide assay and a copper assay.
nucleoplasm Also karyoplasm. All of the material enclosed within the nucleus of a cell by the nuclear envelope, analogous to the cytoplasm enclosed by the main cell membrane. Like the cytoplasm, the nucleoplasm is composed of a gel-like substance (the nucleosol) in which various organelles, nuclear proteins, and other biomolecules are suspended, including nuclear DNA in the form of chromosomes, the nucleolus, nuclear bodies, and free nucleotides.
Release and suppression of growth hormones such as auxin. UV screens to protect against ionizing radiation and to provide coloration (plant pigments). Deterrence of herbivores (sensory properties). Prevention of microbial infections (phytoalexins). Signaling molecules in ripening and other growth processes. In some woods can explain their natural preservation against rot. Flax and Myriophyllum spicatum (a submerged aquatic plant) secrete polyphenols that are involved in allelopathic interactions.
=== 9 May === Two people were killed by Russian shelling in Nikopol. In Russia, the governor of Belgorod Oblast claimed that eight people were injured in a Ukrainian airstrike in Belgorod city. A drone attack on Krasnodar also set a fuel depot on fire. A drone strike was also reported in an oil refinery in Salavat in the first such incident of its kind in the constituent republic of Bashkortostan. The drone used in the attack on Bashkiria was conducted by a drone light aircraft, make unknown, that travelled some 1,500 km. The SBU arrested a resident of Kharkiv on suspicion of spying for Russia. It also claimed to have arrested several individuals in Kyiv on suspicion of attempting to set off bombs on behalf of Russia. Zelenskyy implemented a number of changes in the Ukrainian defense apparatus. He appointed Brigadier General Oleksandr Trepak as commander of the Ukrainian Special Operations Forces, replacing Colonel Serhii Lupanchuk. He also dismissed Valeriy Zaluzhnyi, former commander-in-chief of Ukraine's Armed Forces, from military service "on health grounds", and reappointed Dmytro Hereha as the commander of the Ukrainian Support Forces after replacing him with Oleksandr Yakovets in March 2024. Zelenskyy also dismissed Serhii Rud as director of the State Security Administration. Two colonels were also arrested after being accused of being agents for the Russian FSB. The US Army announced that it would supply three additional HIMARS units paid for by Germany to Ukraine.
Furthermore, sample processing for downstream mass spectrometry (MS) analysis is much more intensive than in NMR application, and results in the destruction of the original sample (via trypsin digestion). Following identification and quantification of metabolites in individual patient samples, NMR and mass spectrometry (MS) output is compiled into a dataset. These datasets include information on the identity and levels of individual metabolites detected within processed samples, as well as characteristics of each metabolite during the detection process (e.g. mass-to-charge ratios for mass spectrometry (MS)-based analysis). Multiple datasets can be created and compiled into large databases for individual patients in order to monitor varying metabolic profiles over a treatment course (i.e. pre- and post-treatment profiles). Each database is then processed through a type of informatics platform with software designed to characterize and analyze the data to generate an overall metabolic profile for the patient. To generate this overall profile, computational programs are designed to:
Sources: en.wikipedia.org
=== November === 9 November – Jozef Puška was convicted of the murder of Ashling Murphy. 12 November – Met Éireann issued a Status Red wind warning for 14 counties, ahead of Storm Debi warning of a "potential danger to life". 15 November – The Dáil voted 85–55 to reject a motion by the Social Democrats party to expel the Israeli Ambassador, Dana Erlich. A Sinn Féin party motion to refer Israel to the International Criminal Court because of its actions in Gaza was also defeated, 77–58. Social Democrats leader Holly Cairns argued during the debate that "Israel is killing with impunity. According to the World Health Organisation, Gaza is now a graveyard for children." She also stated, "Words of condemnation are not enough. We need action. There must be consequences for the crimes perpetrated by Israel on a captive civilian population in Gaza." Deputy James Browne (Fianna Fáil party) claimed in the debate that the Social Democrats' motion "seeks to push Ireland to the margins of international opinion". Meanwhile, a large crowd outside Leinster House called for the ambassador's expulsion. 17 November – Jozef Puška was sentenced to life imprisonment for the murder of Ashling Murphy. 18 November – Gardaí began a murder investigation after a 23-year-old man was shot dead in a gangland shooting in Finglas, Dublin. 21 November – The Minister for Justice Helen McEntee sought approval from the Cabinet for the repeal of antique censorship laws.
=== Alzheimer's disease === Neurons require cholesterol to function. Cholesterol is imported into the neuron by apolipoprotein E (apoE) via LRP1 receptors on the cell surface. It has been theorized that a causal factor in Alzheimer's is the decrease of LRP1 mediated by the metabolism of the amyloid precursor protein, leading to decreased neuronal cholesterol and increased amyloid beta. LRP1 is also implicated in the effective clearance of Aβ from the brain to the periphery across the blood-brain barrier. LRP1 mediates pathways that interact with astrocytes and pericytes, which are associated with the blood-brain barrier. In support of this, LRP1 expression is reduced in endothelial cells as a result of normal aging and Alzheimer's disease in humans and animal models of the disease. This clearance mechanism is modulated by the apoE isoforms, with the presence of the apoE4 isoform resulting in reduced transcytosis of Aβ in in-vitro models of the blood-brain barrier. The reduced clearance appears to be, at least in part, as a result of an increase in the ectodomain shedding of LRP1 by sheddases, resulting in the formation of soluble LRP1 which is no longer able to transcytose the Aβ peptides. In addition, over-accumulation of copper in the brain is associated with reduced LRP1 mediated clearance of amyloid beta across the blood brain barrier. This defective clearance may contribute to the buildup of neurotoxic amyloid-beta that is thought to contribute to Alzheimer's disease.
A 4-month-old baby dies after a boat overloaded with more than 60 migrants sank attempting to cross the Channel from France to England. 2024 United Kingdom riots: Former childminder Lucy Connolly is sentenced to 31 months in prison over an online post in which she called for hotels housing asylum seekers to be set on fire. 18 October King Charles III and Queen Camilla arrive in Australia for their royal tour, Charles's first visit to the country since becoming King. The body of Scotland's former first minister, Alex Salmond, is flown back to Scotland from North Macedonia in a private jet paid for by Scottish businessman Tom Hunter. The Met Office warns of strong winds, potentially reaching 80 mph, along with heavy rain, ahead of the expected arrival of Storm Ashley. 647 migrants cross the English Channel. 19 October BBC News reports that the UK government is exploring how to hand over ownership of the Post Office to thousands of subpostmasters. In a Sunday Times interview, Olympic cyclist Sir Chris Hoy says that he has been told by doctors he has terminal cancer. 20 October The UK government announces plans to appoint a minister to oversee the building of HS2, as well as confirming it will not reinstate the route's Birmingham to Manchester leg. An amber weather alert is in place for western Scotland and the north and west of Northern Ireland as Storm Ashley arrives in the UK; yellow alerts are issued for other parts of Scotland, Northern Ireland and the Welsh coast.
Sources: en.wikipedia.org
heat-shock protein (HSP) Any of a highly conserved family of proteins found in virtually all living organisms and expressed in response to a diverse variety of environmental stressors, including extreme heat or cold, ultraviolet radiation, and oxidative damage. These proteins primarily serve as molecular chaperones, stabilizing other proteins in order to ensure proper folding or to help refold those that have been damaged by the stress. Transcription of many HSP genes is dramatically upregulated as part of the heat shock response pathway.
After the resignations of Kissinger's aides, Nixon took away the authority to tap phones, which he had given Kissinger in May 1969, and gave it to the attorney general, John Mitchell. Unknown to Kissinger, Mitchell had been illegally tapping his phone since the fall of 1969. Adding to the tension, on 2 May 1970, U.S. aircraft bombed North Vietnam for the first time since 1968, causing Senator Fulbright to say, "Good God", when he heard the news. Senate Majority Leader Mike Mansfield said he had trouble believing that Nixon and Kissinger were so reckless. To Nixon, Kissinger accused Laird and/or Rogers of leaking the news of the bombing raid on North Vietnam and asked for the FBI to tap their phones. Without informing Nixon, on 4 May 1970, Laird announced the end of the bombing raids on North Vietnam. On the night of 8 May 1970, Nixon, who had been rattled by the protests, stayed up all night, drinking heavily and randomly phoning people he knew. Between 11:00 pm–2:00 am, Nixon made forty calls, with Kissinger receiving eight of the calls. The Cambodian "incursion" saw American and South Vietnamese troops take the areas of eastern Cambodia that American commanders called the Fish Hook and Parrot's Beak and capture an impressive haul of arms originating from China and the Soviet Union. However, the majority of Vietnamese Communist forces had withdrawn deeper into Cambodia before the invasion, with only a small number left behind to wage a fighting retreat to avoid charges of cowardice.
== Health implications == Fetal microchimerism could have an implication on maternal health. Isolating cells in cultures can alter the properties of the stem cells, but in pregnancy the effects of fetal stem cells can be investigated without in vitro cultures. Once characterized and isolated, fetal cells that are able to cross the blood brain barrier could impact certain procedures. For example, isolating stem cells can be accomplished through taking them from sources like the umbilical cord. These fetal stem cells can be used in intravenous infusion to repair the brain tissue. Hormonal changes in pregnancy alter neurogenesis, which could create favorable environments for fetal cells to respond to injury. The true function on fetal cells in mothers is not fully known, however, there have been reports of positive and negative health effects. The sharing of genes between the fetus and mother may lead to benefits. Due to not all genes being shared, health complications may arise as a result of resource allocation. During pregnancy, fetal cells are able to manipulate the maternal system to draw resources from the placenta, while the maternal system tries to limit it.
Sources: en.wikipedia.org
It is the copper complex of the tripeptide glycyl-L-histidyl-lysine. The metal ion is held by the histidine imidazole group and the peptide N-terminus. Most research on it concerns skin and wound models.
The tripeptide was first isolated from human plasma and has also been reported in saliva and urine. Plasma levels appear to decline with age in some small studies. Those observations rest on limited sample sizes.
It is not authorized as a systemic medicine in most countries. Cosmetic preparations list it as an ingredient rather than an active pharmaceutical substance. Legal status therefore differs by jurisdiction.
GHK denotes the unbound chain of three amino acids. GHK-Cu describes the form in which a copper(II) ion is held by that chain. The two are not interchangeable in solution, since charge, molecular weight, and reactivity differ.