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Melanotan-2 is a synthetic peptide designed as an analog of alpha-melanocyte-stimulating hormone, a signaling molecule produced in the pituitary and skin. Its structure is a linear chain of seven amino acids that folds into a ring through an internal lactam bridge joining two side chains. The compound is sometimes written as MT-II or MEL-2 in informal and commercial contexts. It belongs to the melanocortin peptide family, a group of short signaling molecules that share a conserved core sequence recognized by melanocortin receptors.
Two structural changes distinguish the synthetic peptide from the natural hormone. A norleucine residue replaces methionine at one position, and a D-configured phenylalanine replaces the natural L-form at another. Both substitutions slow enzymatic breakdown, which extends the molecule's persistence relative to the parent hormone. The lactam bridge further constrains the backbone into a stable conformation. These features are standard design strategies in peptide chemistry and are not unique to this compound; they appear across many research peptides built for improved stability.
The compound was developed in the late 1980s and early 1990s by academic researchers investigating melanocortin signaling and pigmentation. Early work explored whether synthetic analogs could reproduce effects of the natural hormone under controlled conditions. The molecule never advanced through the full regulatory pathway required for approval as a medicine. From the mid-2000s onward it appeared in unregulated consumer markets, often distributed through informal channels. That gap between research origins and commercial availability shapes how the compound is discussed today.
Solid peptide kept dry at minus twenty degrees Celsius, shielded from light and moisture, is generally considered stable for extended periods. Solutions are divided into single-use aliquots and held at minus twenty or minus eighty degrees Celsius, because repeated freeze-thaw cycles promote aggregation and loss of material to container surfaces. Hydrolysis of the backbone and oxidation of tryptophan are the principal degradation routes in aqueous solution, and both accelerate at ambient temperature. Hygroscopic uptake after a vial is opened can also shift the actual mass weighed, which affects any concentration calculated from it.
Routine characterisation relies on reversed-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres, using a C18 column and a water-acetonitrile gradient containing trifluoroacetic acid. Electrospray ionisation mass spectrometry confirms the expected molecular mass and can reveal truncated or oxidised by-products that co-elute poorly. Sequence and stereochemistry require additional work, such as peptide mapping or amino acid analysis, because a chromatographic purity figure alone does not distinguish a diastereomer from the target peptide. Independent testing of research-grade material frequently shows measured content below the stated label, so a certificate of analysis is best read together with the method that produced it.
Melanotan-2 is handled in the laboratory as a lyophilised powder that dissolves readily in water, dimethyl sulfoxide and dimethylformamide, with limited solubility in ethanol. Stock solutions prepared in an organic solvent often precipitate when diluted into aqueous buffer, so gradual dilution with mixing is standard practice. The peptide carries a tryptophan residue and a histidine residue, both sensitive to oxidation and to alkaline conditions. Working solutions are therefore kept near neutral to slightly acidic pH, protected from light, and consumed within the same working session whenever that is practical.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic cyclic heptapeptide | Analog of alpha-MSH with an internal lactam bridge |
| Molecular weight | Approximately 1024 daltons | Free base value; salt forms differ |
| Appearance | White to off-white powder | Usually supplied as a lyophilized solid |
| Solubility | Freely soluble in water | Poorly soluble in nonpolar solvents |
| Typical storage | −20 °C, dry, protected from light | Repeated freeze-thaw cycles degrade peptides |
Early published reports described melanotan-2 as a tanning agent without sun protection, which means darkening is not the same as protection against ultraviolet radiation. Later studies explored the peptide in erectile dysfunction, hemorrhagic shock, and some skin conditions. No regulator in the United States or Europe has approved it for clinical use. Many products labelled melanotan-2 are sold without approval and their identity and purity are unverified. Its long-term safety in humans remains an open question.
Melanotan-2, also written Melanotan II, is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone. Its sequence is Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, and the lactam bridge between the aspartate and lysine side chains constrains the peptide into a ring. This structural change increases receptor affinity and metabolic stability relative to the native hormone. The compound was created in the 1980s as a research tool for studying pigmentation biology.
Melanocytes are the pigment-producing cells of the skin, and they carry melanocortin-1 receptors on their surface. When the receptor is activated, cyclic adenosine monophosphate rises inside the cell and raises the activity of enzymes such as tyrosinase, which increases melanin output. Melanotan-2 binds melanocortin-1 receptors in vitro and in animal models, and this binding is generally described as the basis for the tanning effect. Other receptors account for different effects: melanocortin-4 receptors contribute to appetite and erectile signalling, while melanocortin-3 and melanocortin-5 receptors contribute to energy balance and exocrine function.
Regulatory status varies by jurisdiction, and the substance is frequently described as unapproved for therapeutic use. Some authorities classify it alongside prescription-only medicines or controlled categories, while others address it through general consumer protection rules. Analytical surveys have reported mismatches between label claims and measured content in products sold online, although the scope of such testing is limited. Whether these discrepancies are widespread remains an open question. Discussion in the literature therefore tends to combine chemistry, supply-chain observation and policy analysis.
The material is commonly handled as a lyophilized powder in sealed vials. The solid dissolves readily in water and in polar organic solvents, producing a clear solution after reconstitution. Light, heat and repeated freeze-thaw cycles are the concerns most often raised in handling guidance, because peptide bonds and the constrained ring can degrade. Working solutions are generally prepared fresh, and material left in solution is treated as less stable than the dry form. These properties shape how laboratories store and aliquot reference material.
In May 2004, the United States Court of Appeals for the Federal Circuit vacated the previous judgment by the US District Court for the Northern District of Illinois, and the case was remanded back for further court proceedings. Teva continued to sell its generic during this time. The patent for Vicoprofen expired on 18 December 2004, officially opening the drug to generic manufacture. In July 2016, the FDA approved another generic equivalent, manufactured by Aurobindo Pharma Limited.
== Management == MASLD warrants treatment regardless of whether the affected person is overweight. MASLD is a preventable cause of death. Guidelines are available from the American Association for the Study of Liver Diseases (AASLD), American Association of Clinical Endocrinologists (AACE) National Institute for Health and Care Excellence (NICE), the European Association for the Study of the Liver (EASL), and the Asia-Pacific Working Party on MASFLD.
== Influence == Although acquitted, McTavish's case often is mentioned in lectures at medical colleges in Britain and is cited in textbooks and academic papers about forensic science and medical malpractice. Colin Norris, a nurse convicted of four murders and an attempted murder in 2008, is said to have been inspired partly by McTavish's case. He murdered his patients with insulin. Norris, a fellow Scottish nurse, grew up only a mile away from Ruchill where McTavish worked. Her case was discussed extensively in lectures at Dundee University when Norris studied there.
Still, during the Soviet era, Jews were encouraged to admire Cossacks as the antitheses of the "parasitic" and "feeble dwellers of the shtetl." A number of Yiddish writers, including Khaim Melamud, Shmuel Gordon, Viktor Fink, and Shmuel Godiner, presented fictionalized accounts of peaceful Jewish-Cossack coexistence, while efforts were made by the pro-Soviet press to present Khmelnytsky as a heroic figure and Cossacks as liberators from the Nazis. Historiography interprets Cossackdom in imperial and colonial terms. In Ukraine, where Cossackdom represents historical and cultural heritage, some people have begun attempting to recreate the images of Ukrainian Cossacks. Traditional Ukrainian culture is often tied in with the Cossacks, and the Ukrainian government actively supports these attempts. The traditional Cossack bulava serves as a symbol of the Ukrainian presidency, and the island of Khortytsia, the origin and center of the Zaporozhian Sich, has been restored. The video game Cossacks: European Wars is a Ukrainian-made game series influenced by Cossack culture. Cossacks are also mentioned outside Europe. The Japanese anime The Doraemons, part of the larger Doraemon anime series, has a Cossack character, Dora-nichov, who is from Russia.
Sources: en.wikipedia.org
=== Structural Variants === The most widely used sortase in biological and medical applications is the SrtA enzyme found in staphylococcus aureus bacteria, which recognizes an LPXTG binding motif. Different sortase enzymes found in staphylococcus and other bacteria have other recognition sequences. SrtB for example recognizes a NPQTN binding sequence. These other sortase variants have different properties including different binding motifs and reaction efficiencies. To use the sortase enzyme in broader applications new variations of the enzyme have been developed to exhibit desired properties. SrtA variants that exhibit similar kinetics and catalytic efficiency to the wild type have been engineered using directed evolution. This process induces mutations in the natural enzyme and selects for mutations that result in the desired properties. SrtA variants have been developed with different binding motifs (LPXSG and LAXTG). Another sortase variant, eSrtA, was specifically developed to have improved kinetics, while still other variants were developed to operate in the absence of calcium.
=== Nationality and travel history === Many nations implement border controls restricting the entry of people of certain nationalities or who have visited certain countries. For instance, Georgia refuses entry to holders of passports issued by the Republic of China. Similarly, since April 2017, nationals of Bangladesh, Pakistan, Sudan, Syria, Yemen, and Iran have been banned from entering the parts of eastern Libya under the control of the Tobruk government. The majority of Arab countries, as well as Iran and Malaysia, ban Israeli citizens, however exceptional entry to Malaysia is possible with approval from the Ministry of Home Affairs. Certain countries may also restrict entry to those with Israeli stamps or visas in their passports. As a result of tension over the Artsakh dispute, Azerbaijan currently forbids entry to Armenian citizens as well as to individuals with proof of travel to Artsakh. Between September 2017 and January 2021, the United States did not issue new visas to nationals of Iran, North Korea, Libya, Somalia, Syria, or Yemen pursuant to restrictions imposed by the Trump administration, which were subsequently repealed by the Biden administration on 20 January 2021. While in force, the restrictions were conditional and could be lifted if the countries affected meet the required security standards specified by the Trump administration, and dual citizens of these countries could still enter if they presented a passport from a non-designated country.
=== Bipolar disorder === Lithium is primarily used as a maintenance drug in the treatment of bipolar disorder to stabilize mood and prevent manic episodes. It is also effective in the acute treatment of manic episodes. It is effective for mania within the first 7 days of treatment. For acute treatment, although recommended by treatment guidelines for the treatment of depression in bipolar disorder, the evidence that lithium is superior to placebo for acute bipolar depression is low-quality. Atypical antipsychotics are considered more effective for treating acute bipolar depressive episodes. Lithium is effective for the long term prevention of bipolar depressive episodes. Lithium treatment was previously considered to be unsuitable for children, however more recent studies show its effectiveness for treatment of early-onset bipolar disorder in children as young as eight. The required dosage is slightly less than the toxic level (representing a low therapeutic index), requiring close monitoring of blood levels of lithium during treatment. Within the therapeutic range there is a dose-response relationship. A limited amount of evidence suggests lithium carbonate may contribute to the treatment of substance use disorders for some people with bipolar disorder. People with bipolar disorder are at a 3 times higher risk for dementia. Lithium reduces the risk of dementia by 50% among people with bipolar disorder.
== External links == Ferring Pharmaceuticals biography Archived 13 August 2010 at the Wayback Machine Ferring Pharmaceuticals Friends of the Royal Textile Academy of Bhutan Polypeptide Laboratories BV Nordic Pharmaceuticals BV Euro-Diagnostica BV Editions Paulsen
International Union of Biochemistry and Molecular Biology (IUBMB) An international non-governmental organization devoted to promoting scientific research and education in the disciplines of biochemistry and molecular biology, primarily by standardizing biochemical nomenclature, developing and publishing laboratory methods, and awarding grants and fellowships to students and researchers.
Sources: en.wikipedia.org
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Algae ( AL-jee, UK also AL-ghee; sing.: alga ) are any of a large and diverse group of photosynthetic organisms. It excludes the land plants (embryophytes). Such organisms range from microscopic unicellular microalgae (including cyanobacteria and phytoplankton) to seaweeds, multicellular macroalgae which may grow up to 50 metres (160 ft) in length. Most algae are aquatic (especially marine), and some form cohesive colonies. Freshwater algae include Charophyta such as the filamentous Spirogyra and the grasslike stoneworts. Most algae are plankton carried passively by water, although some macroalgae have holdfasts for anchorage. Algae are polyphyletic as they have multiple evolutionary origins. Although algae with two-membraned chloroplasts seem to form a paraphyletic group within the clade Archaeplastida, other algae with chloroplasts that have three or more membranes evolved from protists that acquired photosynthesis after engulfing archaeplastids. Chlorophytes, rhodophytes (red algae) and glaucophytes (grey algae) have primary chloroplasts directly derived from endosymbiont cyanobacteria, while diatoms, cryptomonads, euglenoids and phaeophyceae (brown algae) have secondary chloroplasts derived from indirectly endosymbiont red algae or green algae. Most algae are single-celled organisms without roots, leaves, or stems. Most are photoautotrophs and the main primary producers of aquatic ecosystems, although some are mixotrophs that derive metabolic energy both from internal photosynthesis and from foraging external nutrients.
== Signs and symptoms == Rheumatoid arthritis (RA) is a chronic autoimmune disorder that can affect multiple organ systems. It mainly affects fluid filled connections between joints (synovial joints), causing inflammation, pain, and stiffness in the joints. RA also affects other organs in 20–40% of people. RA typically develops slowly and affects both sides of the body. Systemic symptoms such as fatigue, low-grade fevers and weight loss are also seen in RA.
The analysis of the entire complement of phosphorylated proteins in a cell is certainly a feasible option. This is due to the optimization of enrichment protocols for phosphoproteins and phosphopeptides, better fractionation techniques using chromatography, and improvement of methods to selectively visualize phosphorylated residues using mass spectrometry. Although the current procedures for phosphoproteomic analysis are greatly improved, there is still sample loss and inconsistencies with regards to sample preparation, enrichment, and instrumentation. Bioinformatics tools and biological sequence databases are also necessary for high-throughput phosphoproteomic studies.
Dyson, along with 33 other Essendon players, was found guilty of using a banned performance-enhancing substance, thymosin beta-4, as part of Essendon's sports supplements program during the 2012 season. He and his team-mates were initially found not guilty in March 2015 by the AFL Anti-Doping Tribunal, but a guilty verdict was returned in January 2016 after an appeal by the World Anti-Doping Agency. He was suspended for two years which, with backdating, ended in November 2016; as a result, he served approximately fourteen months of his suspension and missed the entire 2016 suburban football season.
Sources: en.wikipedia.org
It is a synthetic seven-amino-acid peptide modeled on alpha-melanocyte-stimulating hormone. It carries two non-natural substitutions and a cyclic bridge that increase its stability relative to the natural hormone. It circulates as a research chemical and is not an approved medicine.
Melanotan-1, also called afamelanotide, is a shorter linear analog with a different amino acid sequence and no lactam ring. It has been evaluated in formal clinical programs, while melanotan-2 has not. The two are distinct molecules and are not interchangeable.
No. Bremelanotide is a related but distinct cyclic peptide that reached approved status for one specific clinical indication. Melanotan-2 is a separate molecule with its own sequence and properties. Shared ancestry in the melanocortin family does not make them the same substance.
Purity is normally stated as an area percentage from high-performance liquid chromatography, for example ninety-five or ninety-eight percent. That figure describes the proportion of ultraviolet-absorbing material eluting as the main peak. It says nothing about water content, counterions, residual solvents or mass fraction of the peptide itself.