This is a working overview of afamelanotide, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-12-28 and is reviewed periodically as new material appears.
Pharmacologically, melanotan-2 behaves as a non-selective agonist across the melanocortin receptor family. Binding at MC1R on dermal melanocytes promotes eumelanin synthesis, which underlies the tanning response described in early human work. Activity at the centrally expressed MC4R receptor is associated with reported effects on appetite and erectile function. Because the peptide does not discriminate strongly among receptor subtypes, attributing any single observed effect to one receptor pathway is generally not possible without selective antagonists or receptor knockout models.
Research interest has centred on photoprotection and pigmentation, with a smaller body of work on appetite and sexual function. Published human data remain limited to small, frequently uncontrolled studies, and the compound has never received marketing approval from a national medicines regulator. Most laboratory work treats it as a pharmacological tool for probing melanocortin signalling in cell culture or animal models. Whether pigmentation changes observed in people translate into measurable protection against ultraviolet-induced DNA damage remains an open question.
Melanotan-2 is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone, the naturally occurring peptide involved in pigmentation signalling. Its sequence is conventionally written as Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, with a lactam bridge joining the aspartate side chain to the lysine side chain. The empirical formula is C50H69N15O9 and the monoisotopic mass lies near 1023.5 daltons. N-terminal acetylation and the D-configured phenylalanine both increase resistance to enzymatic breakdown compared with the parent hormone.
Published pharmacokinetic information is limited and comes mainly from small studies rather than registrational trials. Plasma half-life is usually described as short, on the order of tens of minutes, followed by rapid tissue distribution and clearance of the intact peptide. Metabolites and low concentrations of parent compound have been reported in urine, a detail relevant to anti-doping and forensic testing. Whether repeated exposure changes receptor sensitivity or clearance over time remains an open question. Values differ noticeably between analytical assays, so published numbers should be read as approximate rather than definitive.
Melanotan II is a synthetic cyclic heptapeptide with the sequence Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, corresponding to a molecular formula of C50H69N15O9 and a monoisotopic mass near 1024 daltons. It was designed as a structural analogue of alpha-melanocyte-stimulating hormone, a peptide hormone produced by cleavage of proopiomelanocortin. A lactam bridge between the aspartate and lysine side chains closes the ring, and the C-terminal amide removes a free carboxyl group. Both modifications increase resistance to enzymatic degradation compared with the linear parent hormone. Four substitutions distinguish it from afamelanotide, the linear analogue studied under the name melanotan I.
| Property | Value | Notes |
|---|---|---|
| Common synonyms | Melanotan II; MT-II; N-acetyl-norleucyl-cyclo[Asp-His-D-Phe-Arg-Trp-Lys] amide | Naming follows peptide convention; the numeral distinguishes it from melanotan-1 |
| Molecular formula | C50H69N15O9 | Includes the lactam bridge; no counter-ion assumed |
| Monoisotopic mass | 1023.53 Da | Free base; salts and counter-ions shift the observed value |
| Appearance | White to off-white lyophilised powder | Batch-to-batch colour variation is not itself proof of impurity |
| Typical analytical method | RP-HPLC purity determination with ESI-MS identity confirmation | Retention time alone does not establish sequence identity |
=== Chronic pain === Under normal conditions, pain conduction begins with some noxious signal followed by an action potential carried by nociceptive (pain sensing) afferent neurons, which elicit excitatory postsynaptic potentials (EPSP) in the dorsal horn of the spinal cord. That message is then relayed to the cerebral cortex, where we translate those EPSPs into "pain". Since the discovery of astrocyte-neuron signaling, our understanding of the conduction of pain has been dramatically complicated. Pain processing is no longer seen as a repetitive relay of signals from body to brain, but as a complex system that can be up- and down-regulated by a number of different factors. One factor at the forefront of recent research is in the pain-potentiating synapse located in the dorsal horn of the spinal cord and the role of astrocytes in encapsulating these synapses. Garrison and co-workers were the first to suggest association when they found a correlation between astrocyte hypertrophy in the dorsal horn of the spinal cord and hypersensitivity to pain after peripheral nerve injury, typically considered an indicator of glial activation after injury. Astrocytes detect neuronal activity and can release chemical transmitters, which in turn control synaptic activity. In the past, hyperalgesia was thought to be modulated by the release of substance P and excitatory amino acids (EAA), such as glutamate, from the presynaptic afferent nerve terminals in the spinal cord dorsal horn.
According to the Soviet astronomer, the Earth's civilization would be too young to be able to contact another civilization that would certainly be more advanced; the Solar System is too young with its 5 billion years, and the first ancestors of today's man appeared only 6 million years ago at the earliest; the oldest celestial objects are between 10 and 14 billion years old; it is clear that the other civilizations are incomparably older than the human civilization. Therefore, the knowledge of these civilizations must be greater than Earth's, and, he reasoned, they must surely be aware of what humans are doing. Kardashev believed it is probable that the present state of Earth's civilization is only one of the stages through which civilizations pass during their evolution. It is thus possible to define civilization on the basis of this universal characteristic, which allowed Aleksandr Lyapunov to define life as "a highly stable state of matter, which uses information encoded by the states of individual molecules to produce maintaining reactions", which Kardashev calls the "functional definition of civilization".
=== Subtypes of bone sarcoma === Osteosarcoma Chondrosarcoma Poorly differentiated round/spindle cell tumors (includes Ewing sarcoma) Hemangioendothelioma Angiosarcoma Fibrosarcoma/myofibrosarcoma Chordoma Adamantinoma Other: Liposarcoma Leiomyosarcoma Malignant peripheral nerve sheath tumor Rhabdomyosarcoma Synovial sarcoma Malignant solitary fibrous tumor.
Thus, most einsteinium samples are contaminated, and their intrinsic properties are often deduced by extrapolating back experimental data accumulated over time. Other experimental techniques to circumvent the contamination problem include selective optical excitation of einsteinium ions by a tunable laser, such as in studying its luminescence properties. Magnetic properties have been studied for einsteinium metal, its oxide and fluoride. All three materials showed Curie–Weiss paramagnetic behavior from liquid helium to room temperature. The effective magnetic moments were deduced as 10.4±0.3 μB for Es2O3 and 11.4±0.3 μB for the EsF3, which are the highest values among actinides, and the corresponding Curie temperatures are 53 and 37 K.
For example, the internal thoracic artery can be left attached to the subclavian artery while rerouting blood flow to bypass occluded coronary arteries and improve heart circulation. In organ transplantation, in situ is used to describe procedures performed within the donor's body to preserve organ viability. In situ perfusion is a technique employed during organ retrieval to restore blood flow to organs while they remain in their original location. This method minimizes ischemic injury and preserves organ viability for transplantation. In contrast, ex situ machine perfusion involves perfusing the organ outside the donor's body, typically after it has been removed.
Sources: en.wikipedia.org
BOAC threatened to cancel its order, and Heseltine several times summoned the board, who had threatened to resign en masse, to his office, impressing Parkinson by his skills of persuasion. Civil servants were happy that his love of generating headlines helped the cause of Concorde sales. The queen, Princess Margaret and Princess Anne were all seen accompanying Heseltine on board Concorde to drum up publicity. In the summer of 1972 he sent Concorde 002 on a tour of Iran, India, Singapore, Japan and Australia. Heseltine and his wife Anne accompanied the plane as far as Singapore (the press joked that Lee Kuan Yew might not let him in with such long hair), and he met it at Toulouse on the way back, but not a single plane was sold. By this stage there were options to sell 74 Concordes to 17 airlines around the world (the original hope had been to sell 30), but this went wrong because of the rises in the oil price in 1973 and 1979; in the event only 10 were ever sold, five each to British Airways (as BOAC had become in 1974) and Air France. Heseltine won praise for his efforts at salesmanship, but some civil servants felt that he was more committed to the plane than Tony Benn had been, and that he should have acted decisively to cut back marketing efforts sooner than he did. He did not mention Concorde at all in his books Where There's A Will or The Challenge of Europe. Heseltine was a key mover in the setting up of the European Space Agency (ESA) in 1973. He cancelled the British Geostationary Technological satellite and handed back the grant to the Treasury.
Tyrosine-specific protein kinases (EC 2.7.10.-) phosphorylate tyrosine amino acid residues, and like serine/threonine-specific kinases are used in signal transduction. They act primarily as growth factor receptors and in downstream signaling from growth factors. Some examples include:
== Select publications == Müller, Thomas; Badu-Tawiah, Abraham; Cooks, R. Graham (2012). "Accelerated Carbon-Carbon Bond-Forming Reactions in Preparative Electrospray". Angewandte Chemie International Edition. 51 (47): 11832–11835. doi:10.1002/anie.201206632. ISSN 1521-3773. PMID 23042619. Badu-Tawiah, Abraham K.; Eberlin, Livia S.; Ouyang, Zheng; Cooks, R. Graham (2016). "Faculty Opinions recommendation of Chemical aspects of the extractive methods of ambient ionization mass spectrometry". Annual Review of Physical Chemistry. 64: 481–505. doi:10.1146/annurev-physchem-040412-110026. PMID 23331308. Damon, Deidre E.; Davis, Kathryn M.; Moreira, Camila R.; Capone, Patricia; Cruttenden, Riley; Badu-Tawiah, Abraham K. (10 February 2016). "Direct Biofluid Analysis Using Hydrophobic Paper Spray Mass Spectrometry". Analytical Chemistry. 88 (3): 1878–1884. doi:10.1021/acs.analchem.5b04278.s001. PMID 26730614.
=== 1997 === 24 August Secrets of the Super Psychics, about Uri Geller and others, made by Open Media 8 September Black Holes, astronomer Phil Charles; the Japanese Ginga (satellite) and V404 Cygni, which orbits a black hole; the William Herschel Telescope in La Palma; Woolsthorpe Manor, south of Grantham, where over 18 months in 1665, Newton deduced the laws of physics; Sir Martin Rees, the Astronomer Royal; vicar John Michell of Thornhill, West Yorkshire; physicist Kip Thorne of Caltech, who made a bet with Stephen Hawking in 1997 - the Thorne–Hawking–Preskill bet; Igor Dmitriyevich Novikov of the Theoretical Astrophysics Center of the University of Copenhagen; Sir Roger Penrose; the Magellanic Clouds are the nearest neighbouring galaxy; the radio galaxy Messier 87 looked at by the Array Operations Center of the National Radio Astronomy Observatory at Sorroco, New Mexico - in March 2021, this would be the first black hole to be photographed, by the Event Horizon Telescope. Narrated by John Hurt, produced by Heather Couper, directed by Richard Smith, made by Pioneer Film And Television Productions, with ABC of Australia and the Discovery Channel.
Sources: en.wikipedia.org
Opioids are among the world's oldest known drugs. The earliest known evidence of Papaver somniferum in a human archaeological site dates to the Neolithic period around 5,700–5,500 BCE. Its seeds have been found at Cueva de los Murciélagos in the Iberian Peninsula and La Marmotta in the Italian Peninsula. Use of the opium poppy for medical, recreational, and religious purposes can be traced to the fourth century BC, when ideograms on Sumerians clay tablets mention the use of "Hul Gil", a "plant of joy". Opium was known to the Egyptians, and is mentioned in the Ebers Papyrus as an ingredient in a mixture for the soothing of children, and for the treatment of breast abscesses. Opium was also known to the Greeks. It was valued by Hippocrates (c. 460 – c. 370 BC) and his students for its sleep-inducing properties, and used for the treatment of pain. The Latin saying "Sedare dolorem opus divinum est", trans. "Alleviating pain is the work of the divine", has been variously ascribed to Hippocrates and to Galen of Pergamum. The medical use of opium is later discussed by Pedanius Dioscorides (c. 40 – 90 AD), a Greek physician serving in the Roman army, in his five-volume work, De Materia Medica. During the Islamic Golden Age, the use of opium was discussed in detail by Avicenna (c. 980 – June 1037 AD) in The Canon of Medicine. The book's five volumes include information on opium's preparation, an array of physical effects, its use to treat a variety of illness, contraindications for its use, its potential danger as a poison and its potential for addiction.
While most definitions of tissue engineering cover a broad range of applications, in practice, the term is closely associated with applications that repair or replace portions of or whole tissues (i.e. organs, bone, cartilage, blood vessels, bladder, skin, muscle etc.). Often, the tissues involved require certain mechanical and structural properties for proper functioning. The term has also been applied to efforts to perform specific biochemical functions using cells within an artificially created support system (e.g. an artificial pancreas, or a bio artificial liver). The term regenerative medicine is often used synonymously with tissue engineering, although those involved in regenerative medicine place more emphasis on the use of stem cells or progenitor cells to produce tissues.
=== Manual solutions === Manual methods such as HEPA filtered vacuuming serves as a backup to eliminating mold via environmental control. HEPA vacuums possess air filters that do not allow mold to be spread into the air again. Installing drying fans, wiping dry books and surrounding furniture, as well as air ducts and shelves will also help to prevent further infestations. In extreme cases, some books and items are discarded to protect the rest of the collection from being affected. These preservation activities are provided by available library staff or hired contractors.
=== Pharmacogenomics === Individual polymorphisms of the cytochrome P450-2D6 enzyme, and more over the isolated indocine metabolite from the inhabitation of CPY134a, with a varied rate of gustation due to physiological factors affect the ability of individuals to metabolize harmine.
This infuriated American colonists and led to the Boston Tea Party, where 90,000 pounds of EIC tea were dumped into the Boston Harbor. As news spread, tea was destroyed throughout the colonies. In Greenwich New Jersey for example, chests of tea were burned in Market Square. As a consequence of these acts and the American revolution (1765–1791), tea drinking became seen as unpatriotic. One article in the Boston Gazette on 15 August, 1768 stated: “Let us abjure the poisonous baneful plant and its odious infusion – poisonous and odious, I mean, not on account of its physical qualities but on account of the political diseases and death that are connected with every particle of it.” Boycotts of tea by revolutionary patriots led to an increase in consumption of other beverages, such as coffee, yaupon tea, or herbal teas infused with peppermint, sage or dandelions. In spite of the distaste for tea that was fueled by the revolution, tea continued to be used by Americans, especially after the war. For example, George Washington regularly had tea for breakfast and dinner, in the English fashion. American merchants Samuel Shaw and Robert Morris sent the first merchant ship to China (the Empress of China) and soon Chinese tea was being shipped to America by American merchant vessels.
Sources: en.wikipedia.org
It is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone, containing seven amino acids with a lactam ring and a D-configured phenylalanine residue. It is supplied as a lyophilised powder for laboratory research.
The natural hormone is a linear tridecapeptide that is rapidly degraded in circulation. Melanotan-2 is shortened, cyclised, N-terminally acetylated, and carries a D-amino acid substitution, all of which slow enzymatic breakdown.
No national medicines regulator has approved melanotan-2 for therapeutic or cosmetic use. In several jurisdictions it is treated as an unapproved prescription medicine, and its legal classification differs from country to country.
No. It is a synthetic analogue carrying four amino acid changes, a lactam ring and an amidated C-terminus. The natural hormone is a linear thirteen-amino-acid peptide processed from proopiomelanocortin.