Everything below concerns chromatographic purity. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-10-12. Where a claim depends on a specific study, the study is described rather than over-claimed.
The peptide portion consists of three amino acids: glycine, histidine and lysine. Copper(II) coordinates through the imidazole nitrogen of histidine, the alpha-amino group of glycine and a deprotonated amide nitrogen of the backbone, producing a roughly square-planar geometry. This arrangement gives the complex its characteristic blue-to-violet colour and helps it resist dissociation in water. Reported stability constants are high, although values differ between studies because of differences in ionic strength and measurement method.
The International Nomenclature of Cosmetic Ingredients lists the substance as copper tripeptide-1, the name that appears on most topical product labels. Related designations include copper peptide and GHK-Cu, and the hyphenated form is common in research literature. In cosmetics the material is regulated as an ingredient rather than as a drug, so products may reach the market without evidence of the effects claimed for them. Whether those effects are clinically meaningful is an open question, since most supportive data come from laboratory work and small trials.
Analytical verification commonly relies on high-performance liquid chromatography for purity assessment and mass spectrometry for identity confirmation. Spectroscopic methods such as UV-visible absorption and electron paramagnetic resonance can probe the metal centre itself, since the d9 configuration of copper(II) produces characteristic signals. Elemental analysis or plasma-based techniques quantify copper content. Because each method reports a different aspect of the same sample, purity figures are most meaningful when the technique and its detection wavelength are stated alongside the value.
Stability of the complex in solution depends on pH, temperature, and the presence of competing ligands. It is generally described as more resistant to breakdown than the metal-free chain, since coordination reduces susceptibility to enzymatic attack. Oxidation and hydrolysis can nevertheless proceed over time in aqueous media. Storage guidance in laboratory settings commonly involves refrigeration, protection from light, and avoidance of strongly alkaline conditions. Published data on long-term behaviour vary considerably and depend on the specific matrix.
| Property | Value | Notes |
|---|---|---|
| INCI name | Copper tripeptide-1 | Standard designation on cosmetic ingredient labels |
| Peptide sequence | Gly-His-Lys | Three-residue ligand; binding occurs at the histidine side chain |
| Metal-to-peptide ratio | 1 to 1 | One copper(II) ion per peptide unit |
| Appearance | Blue to violet powder | Colour arises from copper-to-peptide electronic transitions |
| Water solubility | Freely soluble | Commonly formulated in aqueous or water-alcohol systems |
The molecular weight and charge of GHK-Cu depend on the pH and the number of coordinated ligands. At neutral pH, the peptide typically binds one copper ion, but ternary complexes with other biomolecules can form. Spectroscopic methods such as electron paramagnetic resonance and circular dichroism are used to study the coordination environment. Reports on the exact geometry vary because the complex is dynamic in solution. Researchers often use synthetic GHK-Cu rather than extracted material to control stoichiometry and purity.
GHK-Cu is a coordination complex formed from the tripeptide glycyl-L-histidyl-L-lysine and a copper(II) ion. The peptide binds copper through its histidine imidazole nitrogen, the terminal amino group, and the deprotonated amide nitrogen. This arrangement creates a square-planar or distorted geometry around the metal center, depending on pH and the presence of competing ligands. The complex occurs naturally in human plasma, saliva, and urine at low concentrations, and its sequence is conserved across many vertebrate species.
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 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.
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.
Solid GHK-Cu is usually supplied as a lyophilized powder and is kept cold and dry. Moisture, light, and repeated temperature cycling shorten its useful life in the laboratory. In aqueous solution the complex undergoes slow hydrolysis of the peptide backbone and gradual loss of coordinated copper. Buffers containing strong chelators, such as EDTA, compete for the metal and strip it from the peptide. Working solutions are therefore prepared shortly before use, and leftover liquid is not returned to the stock container.
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.
Nicotinamide riboside kinase 2 is an enzyme that in humans is encoded by the NMRK2 gene (previously ITGB1BP3). As a nicotinamide riboside kinase (EC 2.7.1.22), this enzyme functions to phosphorylate nicotinamide riboside which produces nicotinamide mononucleotide, an important enzyme cofactor. Nicotinamide riboside kinase 2 is primarily found in the muscle and heart, unlike the other known human isoform, nicotinamide riboside kinase 1, which is more widely expressed.
=== Greg Grayson === Greg Grayson (Ben Lloyd-Hughes) is a VP on Pierpoint's CPS desk. He is initially romantically interested in Harper; she rejects his advances, but the two remain friends afterwards. Greg copes with Pierpoint's ruthless culture using drugs, and also explores writing in his spare time, which Eric publicly mocks him for. During an office Christmas party, Harper tells Robert to look after Greg and make sure he stays sober, but Robert and Greg end up indulging in heavy drug use with a client, culminating in Greg running headfirst into a window and injuring himself. Greg leaves Pierpoint after the incident. In series 2 it is revealed that Greg has had a book published. Greg briefly reappears at the end of series 3, now working as a venture capital investor in California. He listens to a sales pitch from Robert for Little Labs, a startup producing medicinal psilocybin.
=== Use in traditional medicine === In modern South Korea, S. mutilans and other Scolopendra species are used in Korean traditional medicine. The centipedes are used whole to treat various medical issues, including joint problems (which is its major use), alopecia areata, stroke, convulsions, lymphangitis, lumps or masses, neoplasm, poisonous tumours, carbuncles, and snake bites. These centipedes were considered one of the most prescribed, medically important, and expensive insect/arthropod drugs in Korean traditional medicine. They are frequently prescribed alone, despite arthropod drugs are usually prescribed with a mix of other medicinal materials for desired effects. In China, S. mutilans is the only centipede species registered for clinical application by the Pharmacopeia of the People's Republic of China. Despite being the only species listed, other species of centipedes, including S. mojiangica, S. multidens, and S. negrocapitis, were also regularly used as substitutes in clinical practice.
== Market share == While there are many different ways to sequence DNA, only a few dominate the market. In 2022, Illumina had about 80% of the market; the rest of the market is taken by only a few players (PacBio, Oxford, 454, MGI)
== Clinical significance == ALT is commonly measured clinically as part of liver function tests and is a component of the AST/ALT ratio. When used in diagnostics, it is almost always measured in international units/liter (IU/L) or μkat. While sources vary on specific reference range values for patients, 0-40 IU/L is the standard reference range for experimental studies.
Sources: en.wikipedia.org
Around this time, a coachbuilder company called PT. Marvia Graha Motor (owned by Marvy Apandi, the executive director of Indomobil Group) built around 50 units replica of Porsche 911 (964) based on MR90 hatchbacks. While retaining the original 1.4-litre engine, 5-speed manual gearbox, suspension and dashboard (later models has 964 dashboard replica), the body was made from fiberglass by using the 964 production tools from VW Group. At that time Indomobil had a trial by assembling two Porsche 964 and planned to build Porsche and Audi in Indonesia to compete with BMW and Mercedes-Benz. The plan was terminated because the production quality was below VW Group's standard.
=== Manipulating the interactions === The protein–DNA interactions can be modulated using stimuli like ionic strength of the buffer, macromolecular crowding, temperature, pH and electric field. This can lead to reversible dissociation/association of the protein–DNA complex.
=== Temporary measures === Several medical treatments shift potassium ions from the bloodstream into the cellular compartment, thereby reducing the risk of complications. The effect of these measures tends to be short-lived, but may temporarily alleviate the problem until potassium can be removed from the body.
A public university, state university, or public college is a university or college that is owned by the state or that receives significant funding from a government. Whether a national university is considered "public" varies from one country (or region) to another, largely depending on the specific education landscape. In contrast a private university is usually owned and operated by a private corporation (not-for-profit or for profit). Both types are often regulated, but to varying degrees, by the government.
Written during the Eastern Han dynasty between 200 and 250 CE, it was the combined effort of practitioners in the Qin and Han dynasties who summarized, collected and compiled the results of pharmacological experience during their time periods. It was the first systematic summary of Chinese herbal medicine. Most of the pharmacological theories and compatibility rules and the proposed "seven emotions and harmony" principle have played a role in the practice of medicine for thousands of years. Therefore, it has been a textbook for medical workers in modern China. The full text of Shennong Ben Cao Jing in English can be found online.
Sources: en.wikipedia.org
It is a complex of a three-amino-acid peptide, glycine, histidine and lysine, bound to a single copper(II) ion. The metal is held mainly by the histidine side chain and the peptide backbone. Most commercial material is supplied as an acetate salt rather than as the free complex.
The free peptide was reported in 1973 by Loren Pickart, who isolated it from human plasma. Its copper-binding behaviour was characterised over the following years. The metal-bound form has been the subject of most later research.
Yes. Copper tripeptide-1 is the name used in cosmetic ingredient labelling, while GHK-Cu is the shorthand found in the scientific literature. Both refer to the same peptide-copper complex, and the two terms are interchangeable in most technical documents.
Reverse-phase high-performance liquid chromatography with ultraviolet detection is the most common approach. Purity is expressed as a share of total peak area at a specified wavelength. Mass spectrometry is then used to confirm molecular identity.