cyclic heptapeptide 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.
Last reviewed on 2025-10-23. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Receptor binding at MC1R on melanocytes raises intracellular cyclic AMP and increases expression of tyrosinase and related enzymes. The downstream result is greater synthesis of eumelanin, the dark pigment, without ultraviolet exposure acting as the trigger. The compound is not selective, however, and also engages MC3R, MC4R and MC5R, which are expressed in the central nervous system and elsewhere. That lack of selectivity is the explanation usually offered for effects reported outside pigmentation, including appetite suppression and nausea. Selectivity remains a central theme in comparative studies of related peptides.
Human data remain limited and mostly short-term. Reports describe small trials and observational accounts rather than large controlled studies, so questions about dose-response relationships and long-term effects on melanocytes stay open. Whether repeated exposure alters naevus behaviour is not settled in the published record. Researchers also note that self-administered use outside clinical settings makes actual exposure difficult to quantify. Statements about efficacy and safety should therefore be read as preliminary rather than established.
| 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 |
Structurally, Melanotan-2 retains the core recognition motif of alpha-melanocyte-stimulating hormone while adding a lactam bridge that links two side chains and constrains the molecule into a ring. This modification lowers susceptibility to enzymatic degradation. The compound acts as an agonist at melanocortin receptors, particularly subtypes associated with melanin production. Because the same receptor family influences several physiological processes, researchers note that its activity is not confined to pigmentation alone. Receptor selectivity continues to be examined in published studies.
Melanotan-2 is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone, a naturally occurring peptide involved in pigmentation signalling. Its sequence incorporates modified residues that increase potency and extend biological activity relative to the native hormone. The compound binds receptors of the melanocortin family and is examined mainly in laboratory research. It does not occur naturally and exists only as a manufactured chemical entity produced by solid-phase synthesis.
The peptide was developed during the 1980s by researchers investigating melanocortin signalling and skin pigmentation pathways. Early work focused on analogues of alpha-melanocyte-stimulating hormone that would resist enzymatic breakdown more effectively than the parent molecule. Melanotan-2 emerged from that programme as a shortened, cyclised variant. Reports describing its synthesis and receptor activity later appeared in the scientific literature. Commercial availability grew through unregulated channels rather than through pharmaceutical approval.
== Matching gunshot residue to a specific source == If the ammunition used was specifically tagged in some way by special elements, it is possible to know the cartridge used to produce the gunshot residue. Inference about the source of gunshot residue can be based on the examination of the particles found on a suspect and the population of particles found on the victim, in the firearm or in the cartridge case, as suggested by the ASTM Standard Guide for gunshot residue analysis by scanning electron microscopy/energy dispersive X-ray spectrometry. Advanced analytical techniques such as ion beam analysis (IBA), carried out after scanning electron microscopy, can support further information allowing one to infer about the source of gunshot residue particles. Christopher et al. showed as the grouping behaviour of different makes of ammunition can be determined using multivariate analysis. Bullets can be matched back to a gun using comparative ballistics.
== As a drug target == The oxoglutarate dehydrogenase complex (α-ketoglutarate dehydrogenase complex) is responsible for converting AKG into succinyl-CoA in the citric acid cycle. It is one of the rate-limiting enzymes in the cycle. In breast cancer with lung metasatsis models, inhibiting this enzyme (causing an accumulation of AKG) reduces cancer cell growth; a similar effect is observed with AKG supplementation in mice with B-cell lymphoma. On the other hand, a dysfunction of this enzyme (again causing AKG accumulation) leads to increased lipid peroxidation in CHCHD2-linked Parkinson's disease models and appears to be partly responsible for elevated phosphorylated α-synuclein levels, as improving the function of this complex causes both AKG and phosphorylated α-synuclei to decrease.
March 4, 2002: Law concerning patients' rights and the quality of the healthcare system. March 4, 2002: Law concerning family names: the concept of patronymic name is replaced by that of family name; father and mother can give their family name to their child, according to different modalities (choice of one or the other, or combination of both in an order they have defined). March 4, 2002: Law concerning parental authority. July 1, 2002: Creation of the Ministry Delegate for Parity and Professional Equality. March 18, 2003: Law for internal security; it includes elements related to passive solicitation, and others creating the "aggravating circumstance of committing a crime or offense due to the victim's sexual orientation." April 11, 2003: Law concerning the election of regional councilors and representatives to the European Parliament, as well as public aid to political parties; rule of alternating candidates of each gender on electoral lists. June 18, 2003: Law concerning the transmission of family names. July 30, 2003: Law reforming the election of senators, which includes elements related to representation and parity. November 26, 2003: Law concerning the control of immigration, the residence of foreigners in France, and nationality. December 18, 2003: Social Security Financing Act for 2004. March 15, 2004: Law regulating, in application of the principle of secularism, the wearing of signs or outfits manifesting religious affiliation in public schools, colleges, and high schools.
When naming a complex ion, the ligands are named before the metal ion. The ligands' names are given in alphabetical order. Numerical prefixes do not affect the order. Multiple occurring monodentate ligands receive a prefix according to the number of occurrences: di-, tri-, tetra-, penta-, or hexa-. Multiple occurring polydentate ligands (e.g., ethylenediamine, oxalate) receive bis-, tris-, tetrakis-, etc. Anions end in o. This replaces the final 'e' when the anion ends with '-ide', '-ate' or '-ite', e.g. chloride becomes chlorido and sulfate becomes sulfato. Formerly, '-ide' was changed to '-o' (e.g. chloro and cyano), but this rule has been modified in the 2005 IUPAC recommendations and the correct forms for these ligands are now chlorido and cyanido. Neutral ligands are given their usual name, with some exceptions: NH3 becomes ammine; H2O becomes aqua or aquo; CO becomes carbonyl; NO becomes nitrosyl. Write the name of the central atom/ion. If the complex is an anion, the central atom's name will end in -ate, and its Latin name will be used if available (except for mercury). The oxidation state of the central atom is to be specified (when it is one of several possible, or zero), and should be written as a Roman numeral (or 0) enclosed in parentheses. Name of the cation should be preceded by the name of anion. (if applicable, as in last example) Examples:
Sources: en.wikipedia.org
=== Gig workers === In July 2023, the Karnataka government announced a free life and accident insurance cover of ₹4 lakh for gig workers, consisting of ₹2 lakh each for life and accidental insurance. Lad said the initiative followed representations from gig-worker organizations.
The first functionally characterized de novo gene identified in mice, a noncoding RNA gene, was also described in 2009. In primates, a 2008 informatic analysis estimated that 15/270 primate orphan genes had been formed de novo. A 2009 report identified the first three de novo human genes, one of which is a therapeutic target in chronic lymphocytic leukemia. This was, however, shown to lack sufficient evidence for translation and it is regarded as a lncrna. Since this time, a plethora of genome-level studies have identified large numbers of orphan genes in many organisms, although the extent to which they arose de novo, and the degree to which they can be deemed functional, remain debated.
=== Failed proposed changes === 2015: Proposals to amalgamate local councils in Wellington and Northland were accepted by the Local Government Commission for consideration, although following consultation they ultimately were not formed into a final proposal. The status quo remains. 2015: Amalgamation of four local councils and the regional council in Hawke's Bay was proposed by the Local Government Commission. A district wide referendum was held in Sep-2015, and the proposal was defeated by 66% of voters. 2015: The Local Government Commission received a proposal to review local government arrangements on the West Coast. In August 2016 the Commission decided to progress the application. The Commission then invited alternative applications to the original application. The Commission's call for alternative reorganisation applications or other proposals for change to West Coast local government arrangements closed on 15 March 2017. The Commission received 23 responses, 19 of which made specific proposals for change. In December 2017 the Local Government Commission determined its preferred option for local government reorganisation on the West Coast to be the transfer of district plan preparation from the Buller, Grey and Westland district councils to the West Coast Regional Council. 2017: The Local Government Commission received a proposal to amalgamate the Masterton, Carterton and South Wairarapa District Councils into a combined Wairarapa District Council. The proposal was defeated by referendum with 59% of voters rejecting the proposed merger.
ACE in plasma was discovered by Leonard T. Skeggs, Norman Shumway, and their colleagues in 1956, but at that time there was no known physiological basis for its use in heart failure treatment. That changed in 1962, when the physiological rationale for using vasodilators to reduce afterload in heart failure was established by American cardiologist Edmund Sonnenblick through force-velocity studies of isolated cardiac muscle. These studies demonstrated that the resistance against which the ventricle contracts directly determines its performance—providing the theoretical justification for afterload reduction as a therapeutic strategy that ACE inhibitors would later exploit. Around this time, it was also noted that those who worked in banana plantations in South-western Brazil collapsed after being bitten by a pit viper, leading to a search for a blood pressure lowering component in its venom. Brazilian scientist Sérgio Henrique Ferreira reported a bradykinin-potentiating factor (BPF) present in the venom of Bothrops jararaca, a South American pit viper, in 1965. Ferreira then went to John Vane's laboratory as a postdoctoral fellow with his already-isolated BPF. The conversion of the inactive angiotensin I to the potent angiotensin II was thought to take place in the plasma. However, in 1967, Kevin K. F. Ng and John R. Vane showed plasma ACE is too slow to account for the conversion of angiotensin I to angiotensin II in vivo. Subsequent investigation showed rapid conversion occurs during its passage through the pulmonary circulation.
tobacco acts like a narcotic poison, like opium, and like alcohol, though usually in a less degree". In December 1952, the Reader's Digest reprinted an article titled Cancer by the Carton which outlined the research links between smoking and lung cancer. Prior to World War I, lung cancer was considered to be a rare disease, which most physicians would never see during their career. With the postwar rise in popularity of cigarette smoking, however, came an epidemic of lung cancer. For instance, it is estimated that "35 to 79 percent of excess veteran deaths due to heart disease and lung cancer are attributable to military-induced smoking"
Sources: en.wikipedia.org
Another common system uses Greek letter prefixes as locants, which is useful in identifying the relative location of carbon atoms as well as hydrogen atoms to other functional groups. The α-carbon (alpha-carbon) refers to the first carbon atom that attaches to a functional group, such as a carbonyl. The second carbon atom is called the β-carbon (beta-carbon), the third is the γ-carbon (gamma-carbon), and the naming system continues in alphabetical order. The nomenclature can also be applied to the hydrogen atoms attached to the carbon atoms. A hydrogen atom attached to an α-carbon is called an α-hydrogen, a hydrogen atom on the β-carbon is a β-hydrogen, and so on. Organic molecules with more than one functional group can be a source of confusion. Generally the functional group responsible for the name or type of the molecule is the 'reference' group for purposes of carbon-atom naming. For example, the molecules nitrostyrene and phenethylamine are quite similar; the former can even be reduced into the latter. However, nitrostyrene's α-carbon atom is adjacent to the phenyl group; in phenethylamine this same carbon atom is the β-carbon atom, as phenethylamine (being an amine rather than a styrene) counts its atoms from the opposite "end" of the molecule.
Woods assures Biko that he will meet with a Government official to discuss the matter. Woods then meets with Jimmy Kruger (John Thaw), the South African Minister of Justice, in his house in Pretoria in an attempt to prevent further abuses. Minister Kruger first expresses discontent over their actions; however, Woods is later harassed at his home by security forces, who insinuate that their orders came directly from Kruger. Later, Biko travels to Cape Town to speak at a student-run meeting. En route, security forces stop his car and arrest him asking him to say his name, and he says, "Bantu Stephen Biko". He is held in harsh conditions and beaten, causing a severe brain injury. A doctor recommends consulting a nearby specialist in order to best treat his injuries, but the police refuse out of fear that he might escape. The security forces instead decide to take him to a police hospital in Pretoria, around 700 miles (1,100 km) away from Cape Town. He is thrown into the back of a prison van and driven on a bumpy road, aggravating his brain injury and resulting in his death. Woods then works to expose the police's complicity in Biko's death. He attempts to expose photographs of Biko's body that contradict police reports that he died of a hunger strike, but he is prevented just before boarding a plane to leave and informed that he is now 'banned', therefore not able to leave the country.
Properdin promotes phagocytosis of apoptotic T cells in two ways. One way is through binding to apoptotic T cells, which initiates AP-mediated C3b deposition, promoting cell uptake through CR3-bearing phagocytes. Another way is through properdin binding on T cells and directly mediating phagocytes. Properdin contains abilities to eliminate apoptotic cells in order to reduce harmful inflammatory and autoimmune reactions. Additionally, properdin binds malignant T cell lines, therefore, properdin deficiency may be a risk in the development of specific T cell malignancies. The alternative pathway is not dependent on antibodies. This branch of the complement system is activated by IgA immune complexes and bacterial endotoxins, polysaccharides, and cell walls, and results in producing anaphylatoxins, opsonins, chemotactic factors, and the membrane attack complex, all of which help fight pathogens.
in a particular measurement. The desorption of a molecule from the surface depends on the binding energy of the molecule to the surface and the temperature. The typical overall adsorption rate is thus often a combined result of the adsorption and desorption.
=== 2 May === Russia claimed to have taken Berdychi, near Avdiivka. It also claimed to have shot down a drone over Crimea. Two people were killed in separate Russian attacks in Donetsk and Kharkiv Oblasts.
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.
It is a synthetic cyclic heptapeptide and a non-selective melanocortin receptor agonist. Structurally it is modelled on alpha-melanocyte-stimulating hormone, a peptide that occurs naturally in the body.