Everything below concerns Chelation. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2025-08-16. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
Quality control for GHK-Cu relies on documentation and independent testing rather than a single accepted standard. A certificate of analysis may report peptide purity, copper content, residual solvents, water content, and microbial limits, but the underlying methods and acceptance criteria vary by supplier. Verification can include mass confirmation, amino acid analysis, and comparison with a reference standard when one is available. Open questions include how different copper-binding modes or peptide isomers affect measured activity and whether conventional purity assays capture those differences. Buyers of research-grade material typically need to request raw data rather than rely solely on a summary certificate.
Laboratory characterization of GHK-Cu typically combines separation, spectroscopic, and elemental techniques. Reverse-phase high-performance liquid chromatography is widely used to assess peptide purity, often with ultraviolet detection near the copper-related absorption band or with mass spectrometry for identity confirmation. Because the molecule contains copper, elemental methods such as inductively coupled plasma mass spectrometry or atomic absorption spectroscopy are used to quantify metal content and confirm stoichiometry. No single universal pharmacopeial monograph exists for GHK-Cu. Laboratories therefore validate their own methods, and reported purity values depend on the chosen assay and calibration standards.
Stability of GHK-Cu is influenced by light, oxygen, moisture, pH, and temperature. Solid material is generally kept desiccated and frozen to reduce hydrolysis and oxidation, while aqueous solutions are best prepared fresh or stored cold in aliquots. Repeated freeze-thaw cycles can promote aggregation, precipitation, or peptide degradation. Copper coordination may change under strongly acidic or alkaline conditions, potentially altering the complex's spectroscopic properties. Published long-term stability data for specific matrices, such as cosmetic emulsions or biological buffers, are limited, so shelf-life claims should be treated as formulation-specific rather than universal.
| Property | Value | Notes |
|---|---|---|
| Peptide sequence | Gly-His-Lys | Three amino acids, histidine in the middle |
| Complex formula | C14H22CuN6O4 | One copper(II) ion per peptide |
| Molar mass (complex) | approx. 402.9 g/mol | Depends on counterion and hydration state |
| Appearance | Blue to blue-violet solid | Colour arises from copper coordination |
| Common synonyms | Copper tripeptide-1, GHK-Cu | Naming varies between disciplines |
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 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.
Aqueous solutions of GHK-Cu are less stable than the dry powder. The peptide backbone is vulnerable to hydrolysis at extreme pH, and copper can be stripped from the complex by strong chelating agents such as EDTA or citrate. Oxidising agents and high concentrations of ascorbic acid can reduce copper(II) and change the complex, which is one reason formulators often keep such ingredients in separate phases. How quickly these changes occur under real storage conditions depends on pH, buffer, temperature and packaging, and quantitative data on the subject are limited.
Dry material is normally held cold, commonly at -20 °C for long-term storage and 2 to 8 °C for working quantities, protected from light and moisture. Vials should be allowed to reach room temperature before opening so that condensation does not form on the powder. In liquid formulations the complex is generally kept near neutral to slightly acidic pH, because strongly alkaline conditions favour precipitation of copper hydroxide. Antioxidants or chelate-stabilising excipients are often added, though the specific approaches are proprietary and rarely published in 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.
Endogenous GHK occurs in blood plasma, saliva, and urine, and reported plasma concentrations decline with age in several studies. Researchers have proposed that the peptide acts as a copper carrier that delivers the metal to cells and to sites of injury. That transport role is a hypothesis supported by binding measurements and tissue-distribution data rather than a settled mechanism, and the peptide is generally described as a minor contributor to total plasma copper transport. Values reported in wound fluid and certain tissue extracts are higher than in circulating plasma.
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.
19 January – The European Court of Human Rights announces that Ireland launched legal action against the United Kingdom on 17 January over the Northern Ireland Troubles (Legacy and Reconciliation) Act 2023. The UK government gives its backing to the Pet Abduction Bill, a private member's bill that makes it illegal to steal cats and dogs in England and Northern Ireland. 20 January – A speech to the Fabian Society conference by Shadow Foreign Secretary David Lammy is interrupted by pro-Palestinian protestors. 21 January – Scotland's First Minister, Humza Yousaf, tells the BBC's Sunday with Laura Kuenssberg he is willing to work with Sir Keir Starmer if he becomes prime minister after the next general election. 22 January – The House of Lords votes 214–171 in favour of an amendment to the Safety of Rwanda (Asylum and Immigration) Bill that calls for the delay of ratification of the bill until Rwanda improves its asylum procedures. The UK government rejects calls from Welsh MPs to add the Six Nations Championship to the list of guaranteed free-to-air sporting events on British television. 23 January – Following more air strikes against Houthi targets, Sunak tells Parliament the UK would not hesitate to launch further strikes if the rebel group continue to attack shipping targets in the Red Sea, but does not seek confrontation with them.
Kunitz-type serine protease inhibitor APEKTx1 is a peptide toxin derived from the sea anemone Anthopleura elegantissima. This toxin has a dual function, acting both as a serine protease inhibitor and as a selective and potent pore blocker of Kv1.1, a shaker related voltage-gated potassium channel. APEKTx1 is a potent toxin purified from the sea anemone A. elegantissima. Besides APEKTx1, other toxins such as APETx1, APE1-1, APE1-2, APE2-2, ApC, and APETx2 have been identified in A. elegantissima. This peptide has 65 amino acids crosslinked by 3 disulphide bridges, and has a molecular mass of 7475 Da. It acts as a monomer. The toxin belongs to the type 2 sea anemone peptides targeting voltage-gated K channels. Other type 2 toxins are the kalicludines from Anemonia sulcata, which selectively block Kv1.2 channels, and SHTX II from Stichodactyla haddoni. Structural homology is also shared with the basic pancreatic trypsin inhibitor (BPTI), a very potent Kunitz-type protease inhibitor, and dendrotoxins (DTX I and α-DTX), which are potent inhibitors of voltage-gated potassium channels.
The MT-ND6 product is a subunit of the respiratory chain Complex I that is believed to belong to the minimal assembly of core proteins required to catalyze NADH dehydrogenation and electron transfer to ubiquinone (coenzyme Q10). Initially, NADH binds to Complex I and transfers two electrons to the isoalloxazine ring of the flavin mononucleotide (FMN) prosthetic arm to form FMNH2. The electrons are transferred through a series of iron-sulfur (Fe-S) clusters in the prosthetic arm and finally to coenzyme Q10 (CoQ), which is reduced to ubiquinol (CoQH2). The flow of electrons changes the redox state of the protein, resulting in a conformational change and pK shift of the ionizable side chain, which pumps four hydrogen ions out of the mitochondrial matrix.
The main function of motilin is to increase the migrating myoelectric complex component of gastrointestinal motility and stimulate the production of pepsin. Motilin is also called "housekeeper of the gut" because it improves peristalsis in the small intestine and clears out the gut to prepare for the next meal. A high level of motilin secreted between meals into the blood stimulates the contraction of the fundus and antrum and accelerates gastric emptying. It then contracts the gallbladder and increases the squeeze pressure of the lower esophageal sphincter. Other functions of motilin include increasing the release of pancreatic polypeptide and somatostatin.
=== Classes === In Team Fortress Classic, the player can choose to play as one of nine classes: the Scout, Sniper, Soldier, Demoman, Medic, Heavy Weapons Guy, Pyro, Spy, or Engineer. Each class comes equipped with at least one weapon unique to that class, and often a secondary weapon which may be common across multiple classes (typically a shotgun or nailgun). Additionally, each class gets a melee weapon (all classes, with the exception of the Medic, Spy, and Engineer, wield a crowbar, an homage to Valve's game Half-Life). Finally, each player carries grenades; the effects of grenades vary, depending on the player's class. In Escort game modes, a player may also choose to play as the Civilian class, which is armed only with an umbrella, no armor, and very little health. Civilians are typically escorted and protected by the rest of the team.
Sources: en.wikipedia.org
=== A10BH Dipeptidyl peptidase 4 (DPP-4) inhibitors === A10BH01 Sitagliptin A10BH02 Vildagliptin A10BH03 Saxagliptin A10BH04 Alogliptin A10BH05 Linagliptin A10BH06 Gemigliptin A10BH07 Evogliptin A10BH08 Teneligliptin A10BH51 Sitagliptin and simvastatin A10BH52 Gemigliptin and rosuvastatin
[Adenosyl−O−PO2−O−PO2−O−PO3]4− + ROH → [Adenosyl−O−PO2−O−PO3H]2− + [RO−P−O3]2− This equation can be written in several ways that are nearly equivalent that describe the behaviors of various protonated states of ATP, ADP, and the phosphorylated product. As is clear from the equation, a phosphate group per se is not transferred, but a phosphoryl group (PO3-). Phosphoryl is an electrophile. This process and its inverse, dephosphorylation, are common in biology. Protein phosphorylation often activates (or deactivates) many enzymes.
== History == Erythritol was discovered in 1848 by the Scottish chemist John Stenhouse and first isolated in 1852. Starting from 1945, American chemists applied newly-developed techniques of chromatography to sugarcane juice and blackstrap molasses, finding in 1950 that erythritol was present in molasses fermented by yeast. It was first approved and marketed as a sweetener in Japan in 1990, and in the US in 1997. In February 1997, Cerestar Holding Co., Mitsubishi Chemical Co., and Nikken Chemicals Co. submitted a formal generally recognized as safe (GRAS) affirmation petition with the US FDA. However, in April 1997 the FDA replaced the GRAS affirmation petition process with the current GRAS notification process, a notice was first filed by Cerestar in April 2001, and the FDA responded with "no questions" in September 2001.
== Function == The pituitary glycoprotein hormone family includes follicle-stimulating hormone, luteinizing hormone, chorionic gonadotropin, and thyroid-stimulating hormone. All of these glycoproteins consist of an identical alpha subunit and a hormone-specific beta subunit. This gene encodes the beta subunit of follicle-stimulating hormone. In conjunction with luteinizing hormone, follicle-stimulating hormone induces egg and sperm production. The FSHB gene in human DNA encodes the follicle-stimulating hormone subunit beta protein (FSH-B), or Follitropin Beta. More specifically, the FSHB gene encodes for the beta subunit of follicle-stimulating hormone (FSH). Therefore, proper transcription of FSHB allows for the proper production of FSH. FSH is a peptide hormone the pituitary gland produces that is involved with the reproductive system. FSH promotes follicular oocyte (egg) production, growth, and maturation and helps control a female's menstrual cycle. Additionally, FSH is involved in the male reproductive system by stimulating spermatogenesis (maturation of sperm cells) and initiating puberty. Studies show that variations in the FSHB gene can contribute to the likelihood of a woman becoming pregnant with fraternal, or dizygotic, twins. This is because certain heritable variations of FSHB contribute to increased production of FSH from the pituitary gland, raising the levels of FSH found in a woman's blood. It is also shown that women with these FSHB variants had their first menstrual cycle, children, and menopause at an earlier age than women without the variant.
Sources: en.wikipedia.org
=== Other uses and occurrences === Pyrolysis is used to turn organic materials into carbon for the purpose of carbon-14 dating. Pyrolysis liquids from slow pyrolysis of bark and hemp have been tested for their antifungal activity against wood decaying fungi, showing potential to substitute the current wood preservatives while further tests are still required. However, their ecotoxicity is very variable and while some are less toxic than current wood preservatives, other pyrolysis liquids have shown high ecotoxicity, what may cause detrimental effects in the environment. Pyrolysis of tobacco, paper, and additives, in cigarettes and other products, generates many volatile products (including nicotine, carbon monoxide, and tar) that are responsible for the aroma and negative health effects of smoking. Similar considerations apply to the smoking of marijuana and the burning of incense products and mosquito coils. Pyrolysis occurs during the incineration of trash, potentially generating volatiles that are toxic or contribute to air pollution if not completely burned. Laboratory or industrial equipment sometimes gets fouled by carbonaceous residues that result from coking, the pyrolysis of organic products that come into contact with hot surfaces.
AB Tetra Pak was established in Lund, Sweden, in 1951 as a subsidiary to Åkerlund & Rausing. In May of that year, the new packaging system was presented to the press, and in 1952, the first filling machine producing 100 ml cream tetrahedrons was delivered to Lundaortens Mejeriförening, a local dairy. In subsequent years, tetrahedron packages became more and more common in Swedish grocery stores, and in 1954, the first machine producing 500 ml milk packages was sold to a Stockholm dairy. That same year, the first machine was exported to Hamburg, Germany, soon to be followed by France (1954), Italy (1956), Switzerland (1957), and later the Soviet Union (1959) and Japan (1962).
== Causes == In 2019, the epidemic was described by Rolling Stone as a "uniquely American problem". In 2017, prescription rates for opioids in the United States were 40 percent higher than the rate in other developed countries such as Germany or Canada. yet the FDA did not fully utilize its regulatory mechanisms to restrict the pharmaceutical industry.
Sources: en.wikipedia.org
The peptide is glycyl-L-histidyl-L-lysine, a three-amino-acid sequence commonly abbreviated GHK. It binds a single copper(II) ion under typical laboratory conditions. The free peptide and the copper complex are separate chemical species with different properties.
The sequence was identified in human plasma in 1973. Early work examined its presence in blood and its proposed role in tissue repair. The copper-binding property was characterized afterward and became the focus of much later research.
The tripeptide has been measured in human plasma and other biological fluids. Whether it circulates mainly as the copper complex or as the free peptide remains an open question. Natural concentrations are low and difficult to measure reliably.
Identification usually combines reverse-phase high-performance liquid chromatography with mass spectrometry. The copper content can be measured separately by inductively coupled plasma mass spectrometry or atomic absorption spectroscopy. The combination helps distinguish the intact complex from free peptide or free copper.