This is a working overview of copper tripeptide-1, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-05-03 and is reviewed periodically as new material appears.
GHK-Cu is the copper-binding complex formed by the tripeptide glycyl-L-histidyl-L-lysine and a copper(II) ion. The free peptide is usually written as GHK, and the complex is written as GHK-Cu or Cu-GHK. The sequence was identified in human plasma and later detected in saliva and urine. Its name comes from the single-letter codes of glycine, histidine and lysine. The complex is widely described as a naturally occurring carrier of copper in blood rather than as a free peptide with its own hormonal role.
Copper binds to the peptide through the histidine imidazole nitrogen and the terminal amino group, forming a stable square-planar complex. Binding constants reported for copper(II) with GHK are high, so the peptide competes effectively for copper in solution. The complex absorbs visible light, which gives solutions a blue to violet colour. Whether the metal-free peptide has a distinct biological function of its own is still an open question; some work treats it mainly as a copper delivery vehicle, while other work reports peptide-specific effects.
The compound was first isolated from human plasma in the 1970s by Loren Pickart, who later described copper-binding activity in liver and other tissues. Early reports focused on its presence in blood and its ability to carry copper between proteins. Commercial and cosmetic use of the term 'copper peptide' has since broadened, and labels rarely distinguish GHK-Cu from other copper-binding fragments. This naming overlap makes literature searching harder, because cosmetic ingredient lists, supplier catalogues and laboratory papers use different vocabularies for the same molecule.
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.
Published work on GHK-Cu concentrates largely on cell culture systems rather than whole organisms. Frequently used endpoints include collagen synthesis, expression of matrix metalloproteinases, and migration of fibroblasts. Some reports describe antioxidant behavior, while others stress delivery of copper into cells. These mechanisms are proposed rather than demonstrated, and the relative weight of each pathway is unclear. Human trials are few and generally small, so laboratory findings should not be read as confirmed clinical results.
| Property | Value | Notes |
|---|---|---|
| Sequence | Gly-His-Lys | Three amino acids; histidine supplies the main copper-binding nitrogen |
| Bound metal | Copper(II) | Coordination is described as square-planar around the metal centre |
| Appearance | Blue to violet solid | Colour originates from copper d-d electronic transitions |
| Solubility class | Freely soluble in water | Aqueous solutions are often slightly acidic |
| Common synonyms | Copper tripeptide, Cu-GHK | Ingredient lists may say only 'copper peptide' without giving the sequence |
GHK-Cu is a coordination complex formed between the tripeptide glycyl-L-histidyl-L-lysine and copper(II). The peptide sequence consists of glycine, histidine, and lysine, and its imidazole and amino groups provide binding sites for the metal ion. In the complex, copper is held through nitrogen donors from the histidine side chain, the N-terminal amine, and deprotonated amide nitrogens. The resulting compound is intensely blue and water-soluble. It occurs naturally in human plasma, saliva, and urine at low concentrations.
The peptide was first isolated from human albumin in 1973 by Loren Pickart, who later described its copper-binding behavior. Early work linked the complex to wound healing and tissue remodeling. Plasma levels of GHK decline with age, a pattern that stimulated interest in topical and supplemental applications. Researchers have reported that the tripeptide influences collagen synthesis, antioxidant defense, and inflammatory signaling in cell and animal models. Human clinical evidence remains limited and often relies on small studies.
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.
The reasons for the strikes called by the illegal Workers' Commissions were fundamentally economic ─ the seriousness of the "1973 oil crisis" was accentuated ─ but they also had political motivations since the demands for wage increases or improvements in working conditions were accompanied by others such as freedom of union, the recognition of the right to strike, freedom of assembly and association, when not directly demanding amnesty for political prisoners and exiles. The government's response was repression. On March 3, 1976, the most serious incidents took place in Vitoria, which resulted in the death of five people by police gunfire. A general strike was immediately declared in the Basque Country and Navarre in solidarity with the victims, which had a huge following ─ also in other areas. For much of the opposition, the "Vitoria massacre" showed the true face of the "Arias-Fraga reform" and demonstrations and strikes intensified, with subsequent clashes with the forces of law and order ─ in Basauri, near Bilbao, another worker died shortly afterwards. In spite of everything, the mobilizations did not have a sufficient following to overthrow the government, much less the "Francoist monarchy".
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direct zoonotic transmission to humans (spillover), assessed as "possible to likely" introduction through an intermediate host followed by a spillover, assessed as "likely to very likely" introduction through the (cold) food chain, assessed as "possible" introduction through a laboratory incident, assessed as "extremely unlikely" The report mentions that direct zoonotic transmission to humans has a precedent, as most current human coronaviruses originated in animals. Zoonotic transmission is also supported by the fact that RaTG13 binds to hACE2, although the fit is not optimal. The investigative team noted the requirement for further studies, noting that these would "potentially increase knowledge and understanding globally."
Sources: en.wikipedia.org
RNA-induced silencing complex (RISC) A ribonucleoprotein complex which works to silence endogenous and exogenous genes by participating in various RNA interference pathways at the transcriptional and translational levels. RISC can bind both single-stranded and double-stranded RNA fragments and then cleave them or use them as guides to target complementary mRNAs for degradation.
This essay discusses the fairy-story as a literary form. It was initially written as the 1939 Andrew Lang Lecture at the University of St Andrews, Scotland. Tolkien focuses on Andrew Lang's work as a folklorist and collector of fairy tales. He disagreed with Lang's broad inclusion, in his Fairy Book collections, of traveller's tales, beast fables, and other types of stories. Tolkien held a narrower perspective, viewing fairy stories as those that took place in Faerie, an enchanted realm, with or without fairies as characters. He viewed them as the natural development of the interaction of human imagination and human language.
=== Later history === The Zaporizhian Sich became a vassal polity of the Polish–Lithuanian Commonwealth during feudal times. Under increasing pressure from the Polish–Lithuanian Commonwealth, in the mid-17th century the Sich declared an independent Cossack Hetmanate. The Hetmanate was initiated by a rebellion under Bohdan Khmelnytsky against Polish and Catholic domination, known as the Khmelnytsky Uprising. Afterwards, the Treaty of Pereyaslav (1654) brought most of the Cossack state under Russian rule. The Sich, with its lands, became an autonomous region under the Russian protectorate. The Don Cossack Army, an autonomous military state formation of the Don Cossacks under the citizenship of the Moscow State in the Don region in 1671–1786, began a systematic conquest and colonization of lands to secure the borders on the Volga, the whole of Siberia (see Yermak Timofeyevich), and the Yaik (Ural) and Terek Rivers. Cossack communities had developed along the latter two rivers well before the arrival of the Don Cossacks.
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== Reactivity ratios == The reactivity ratio of a growing copolymer chain terminating in a given monomer is the ratio of the reaction rate constant for addition of the same monomer and the rate constant for addition of the other monomer. That is,
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Sources: en.wikipedia.org
The letters GHK are the one-letter codes for glycine, histidine and lysine, the three amino acids in the peptide. The suffix Cu indicates that the peptide is bound to a copper ion, normally copper(II).
The free tripeptide and its copper complex have been measured in human plasma, saliva, urine and some tissue extracts. Reported concentrations vary widely between studies, and the role of the complex in normal physiology remains partly unresolved.
The plain peptide lacks the metal, so its charge, colour and binding behaviour differ. The copper complex is blue and carries a bound copper ion, while the metal-free form is colourless and has different solution chemistry.
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.