shelf life comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2025-08-30. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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.
| 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 |
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.
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.
Material described as GHK-Cu appears in several distinct markets, including cosmetic ingredients, laboratory reagents, and consumer products, and the quality expectations attached to each differ. A certificate of analysis generally reports peptide purity by chromatography, copper content, appearance, and residual solvents or counterions. Counterion identity matters, because the complex is usually supplied as an acetate or a similar salt, and the counterion contributes to the measured mass. Independent verification of sequence and metal stoichiometry is advisable when a material is used for quantitative work. Batch-to-batch variation is common and should be documented rather than assumed negligible.
Copper peptide solutions tend to resist degradation better than many free peptides, because the bound metal protects the N-terminus and reduces susceptibility to some peptidases. Backbone hydrolysis, oxidation of the histidine imidazole ring, and photochemical reactions remain the principal degradation routes. Aqueous solutions are generally most stable near neutral to mildly acidic pH, while strongly alkaline conditions accelerate hydrolysis. Light exposure is usually avoided, since both the peptide and the copper center can take part in photochemical processes. Stability data published by suppliers often describe short-term behavior rather than multi-year shelf life.
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.
GHK-Cu is the copper complex of the tripeptide glycyl-L-histidyl-L-lysine, a short sequence found naturally in human plasma, saliva and urine. Loren Pickart reported the isolation of the free peptide in 1973 while studying factors that influenced the growth of aged liver cells in culture. The peptide was later shown to bind copper(II) with high affinity, and the metal-bound form became the focus of most subsequent research. Its concentration in circulation declines markedly with age, a pattern that is well documented, though the physiological consequences of that decline remain debated.
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.
=== Bellagio Center === The foundation also owns and operates the Bellagio Center in Bellagio, Italy. The center has several buildings, spread across a 50-acre (200,000 m2) property, on the peninsula between lakes Como and Lecco in Northern Italy. The center is sometimes referred to as the "Villa Serbelloni", the property bequeathed to the foundation in 1959 under the presidency of Dean Rusk (who was later to become U.S. President Kennedy's secretary of state).
location rhizomelic = root, i.e., bones of the upper arm or thigh mesomelic = middle, i.e., bones of the forearm or lower leg acromelic = end, i.e., bones of hands and feet. micromelic = entire limbs are shortened source chondro = of cartilage osteo = of bone spondylo = of the vertebrae plasia = form trophy = growth Examples include achondroplasia and chondrodystrophy.
Dipeptidase 2 (DPEP2) is a protein which in humans is encoded by the DPEP2 gene. DPEP2 belongs to the membrane-bound dipeptidase (EC 3.4.13.19) family. These enzymes hydrolyze a variety of dipeptides, including leukotriene D4, the beta-lactam ring of some antibiotics, and cystinyl-bis-glycine (cys-bis-gly) formed during glutathione degradation.
In the United States, an El Niño is declared when the Climate Prediction Center, which monitors the sea surface temperatures in the Niño 3.4 region and the tropical Pacific, forecasts that the sea surface temperature will be .5 °C (0.90 °F) above average or more for the next several seasons. The Niño 3.4 region stretches from the 120th to 170th meridians west longitude astride the equator five degrees of latitude on either side, are monitored. It is approximately 3,000 kilometres (1,900 mi) to the southeast of Hawaii. The most recent three-month average for the area is computed, and if the region is more than 0.5 °C (0.9 °F) above (or below) normal for that period, then an El Niño (or La Niña) is considered in progress. In February 2026, anomalous increases in tropical sea surface temperatures caused NOAA to revise the threshold distinguishing La Niña and El Niño from each other. The new method replaces a dependency on a 30-year climate base period with the Relative Oceanic Niño Index (RONI): a comparison of the ENSO region to the global tropics. The Australian Bureau of Meteorology looks at the trade winds, Southern Oscillation Index, weather models and sea surface temperatures in the Niño 3 and 3.4 regions, before declaring an ENSO event. The Japan Meteorological Agency declares that an ENSO event has started when the average five month sea surface temperature deviation for the Niño 3 region is over 0.5 °C (0.90 °F) for six consecutive months or longer.
A nuclear isomer is a metastable state of an atomic nucleus in which one or more nucleons (protons or neutrons) occupy excited state levels (higher energy levels). "Metastable" describes nuclei whose excited states have half-lives of 10−9 seconds or longer, 100 to 1000 times longer than the half-lives of the excited nuclear states that decay with a "prompt" half-life (ordinarily on the order of 10−12 seconds). Some references recommend using a threshold of 5×10−9 seconds to distinguish the metastable half-life from the normal "prompt" gamma-emission half-life. The half-lives of a number of isomers are far longer than this and may be minutes, hours, or years. The most extreme example known is the 180m73Ta nuclear isomer, which survives so long (at least 2.9×1017 years) that it has never been observed to decay spontaneously, and occurs naturally as a primordial nuclide, though uncommonly at only 1/8000 of all tantalum. The second most stable isomer is 210m83Bi, which does not occur naturally; its half-life is 3.04×106 years to alpha decay. The half-life of a nuclear isomer can exceed that of the ground state of the same nuclide, as with the two above, as well as, for example, 186m75Re, 192m277Ir, 212m84Po, 242m95Am and multiple holmium isomers.
Sources: en.wikipedia.org
== Transportation == SST class blimp Supersonic transport, aircraft Training Submarines, (US Navy hull classification symbol: SST) Mitsubishi SST, a concept car by Mitsubishi Twin Clutch SST, a twin-clutch transmission developed by Mitsubishi Safe Secure Trailer, see US Office of Secure Transportation SST, the National Rail station code for Stansted Mountfitchet railway station, Essex, England
== Mistaken portrait == For two centuries, until the discovery of the error in 2005, books, paintings and articles had incorrectly shown a profile portrait of the obscure French politician Louis Legendre (1752–1797) as a portrait of the mathematician. The error arose from the fact that the sketch was labelled simply "Legendre" and appeared in a book along with contemporary mathematicians such as Lagrange. One of only two known portraits of Legendre, rediscovered in 2008, is found in the 1820 book Album de 73 portraits-charge aquarellés des membres de I'Institut, a book of caricatures of seventy-three members of the Institut de France in Paris by the French artist Julien-Léopold Boilly as shown below. The other portrait is from the book Le Panthéon scientifique de la tour Eiffel.
== Notable alumni == Tassaduq Hussain Jillani, 21st Chief Justice of Pakistan Samar Mubarakmand, nuclear physicist Nawabzada Nasrullah Khan, politician Makhdoom Sajjad Hussain Qureshi, former Governor of Punjab Inzamam-ul-Haq, cricketer and former captain of the Pakistan national cricket team Syed Jamshed Ali, former judge of the Supreme Court of Pakistan Faiz Mohammad Khan, medical physicist specialising in radiation oncology Mazhar Kaleem, novelist Tauqeer Nasir, actor and former director-general of the Pakistan National Council of the Arts Muhammad Ali, Lollywood actor Mohsin Naqvi, Urdu poet Irshad Hussain, chemist and nanomaterials scientist Khalid Masood Khan, poet and columnist Ehsan Wyne, lawyer and politician
== Transcript variants == Transcription of C3orf62 produces 5 alternatively spliced variants and 1 unspliced form. Of the four splice variants, two of them are protein coding, one is nonsense meditated decay, and one is a retained intron. QIAGEN denotes the following as transcription factor binding sites in the C3orf62 promoter: TFCP2, Pax-6, p53, MyoD, YY1, Ik-2, AREB6, IRF-7A3.
Sources: en.wikipedia.org
== Personal life == Yates lives in Marbella with his wife, Brazilian fitness model Glauce "Gal" Ferreira, whom he had met at the 2008 Arnold Classic. His son with his ex-wife Deb is also a bodybuilder and the two work closely together. Yates practises yoga every day and has described yoga and meditation as life-altering experiences. He has endorsed the use of psychedelics such as ayahuasca for religious and spiritual purposes. He is open about his cannabis use, which predates his bodybuilding career; in a July 2017 appearance on The Joe Rogan Experience, he stated that cannabis has "anti-cancer" properties and said that he is an advocate for its legalisation for this reason in addition to its relaxing properties and temporary increases in respiratory capacity. Yates revealed his belief in Holocaust denial theories whilst being interviewed by Dave Palumbo in April 2018, claiming that the Holocaust death toll had been "exaggerated" and that two forensic studies (which he did not provide the names of) had concluded that no gas was ever used at the Auschwitz concentration camp.
=== Preparation of samples === Microtox can be applied to a variety of matrices including drinking water, stormwater runoff, effluent, industrial discharges, soils and sediments. Most samples do not require special preparation before testing besides adjusting the salinity to 2%. However, samples that have certain characteristics, such as high turbidity levels, may require special preparation. If samples require a salinity adjustment to lower the salinity, this can be accomplished by adding an appropriate amount of Microtox Osmotic Adjusting Solution to dilute the sample. For example, adding 0.1 mL of MOAS to 1 mL of sample would result in a dilution of 90.9% of the original concentration. If a greater salinity is required, this can be accomplished by dissolving solid sodium chloride in the sample to achieve a final salinity of 2% for the protection of Allivibrio fischeri. Highly turbid samples that contain particulate matter will be required to settle before the test can be conducted. Particulate matter in the sample can interfere with bioluminescence by absorbing light and give misleading test results. Interference of luminescence can also occur with samples which are highly colored (particularly red, brown or black). It may be necessary to centrifuge samples to obtain an acceptable clarity for the test. If samples contain chlorine, this may alter the toxicity to Allivibrio fischeri and also give misleading results. The samples can be de-chlorinated using a sodium thiosulphate and deionized water solution that does not affect test results.
Leena Maria Ala-Kokko (née Hämäläinen; born 20 July 1961) is a Finnish biochemist and molecular biologist. Her research focuses on collagens, in particular those found in cartilage, as well as connective tissue disease. She has worked as a professor both in Finland and in the United States and, with her husband, runs a US-based company that carries out molecular diagnostic testing of connective tissue diseases.
== Properties == Industrially produced vinylene carbonate is usually a yellow to brown liquid. By suitable process control and purification steps, a solid product with a melting point of 20-22 °C and a chlorine content below 10ppm can be obtained. Liquid vinylene carbonate turns rapidly yellow even in the absence of light and must be stabilized by the addition of radical scavengers. In solid form, the highly pure substance is long-term stable when stored below 10 °C. Vinylene carbonate dissolves in a variety of solvents such as ethanol, tetrahydrofuran, ethylene carbonate, propylene carbonate, and other dipolar aprotic electrolyte solvents used for lithium ion rechargeable batteries such as dimethyl carbonate, diethyl carbonate and the like.
Cohn (1993), assistant secretary for strategy, planning, analysis & risk of the United States Department of Homeland Security Amit Bose (1994), acting administrator of the Federal Railroad Administration Karthik Ramanathan (1994), acting assistant secretary of the treasury for financial markets Frank Scaturro (1994), lawyer, public advocate who spearheaded the restoration of Grant's Tomb; Republican candidate for New York's 4th congressional district Radhika Fox (1995), acting assistant administrator for water of the United States Environmental Protection Agency Beto O'Rourke (1995), U.S. congressman for Texas's 16th congressional district and candidate in the 2020 United States presidential election Rebekah Gee (1997), secretary of the Louisiana Department of Health, daughter of Ohio State University president E. Gordon Gee Jay Carson (1999), executive director of C40 Cities Climate Leadership Group; former press secretary for Hillary Clinton and Howard Dean's presidential campaigns John Ray Clemmons (1999), member of the Tennessee House of Representatives from the 55th district George Demos (1999), former U.S.
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(II) complex of the tripeptide glycyl-L-histidyl-lysine, a sequence of three amino acids. The copper ion is held by the histidine imidazole, the terminal amino group, and an amide nitrogen. The bound form is distinct from the free peptide in charge, color, and stability.