A practical reference on Cyclic heptapeptide: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2025-12-03. Anything still debated is marked as such rather than presented as settled.
Early research on PT-141 grew out of work on melanotan II, a related cyclic peptide studied for pigmentation. Investigators observed that centrally acting melanocortin agonists also influenced sexual behaviour in animal models, and the programme shifted toward that endpoint. A nasal formulation was evaluated in clinical trials but showed inconsistent absorption, and later studies used subcutaneous administration instead. Regulatory approval in the United States followed in 2019 for a defined population of premenopausal women with acquired, generalised hypoactive sexual desire disorder. That approval was specific to that group rather than a broad indication.
Bremelanotide acts as a non-selective agonist at melanocortin receptors, with reported activity at MC1R, MC3R, MC4R and MC5R. The proposed basis for its central effects is activation of MC4R populations in the hypothalamus, a region associated with appetite and reproductive signalling. Because the peptide carries a net positive charge and polar side chains, it does not cross biological membranes freely, which is one reason oral administration is not the standard route. Effects generally appear within an hour of parenteral administration and are described as centrally mediated rather than peripheral.
Identity and purity are established with orthogonal methods rather than a single test. Reverse-phase high-performance liquid chromatography with ultraviolet detection gives a purity figure by area normalization, while mass spectrometry confirms the expected molecular ion. Amino acid analysis or peptide mapping can detect sequence errors that a mass value alone would miss, and residual counterion content is sometimes measured separately. Common impurities include truncated sequences, oxidized residues, and deamidated products; reporting them individually is more informative than a single composite purity number.
Lyophilized peptide arrives as a white to off-white cake or powder and is normally held at minus twenty degrees Celsius or colder for extended periods. Short-term bench work at ambient temperature is tolerable for minutes, not hours, because the solid is hygroscopic and picks up moisture that promotes hydrolysis. Vials should stay in a desiccator or a sealed bag with desiccant, protected from light, since aromatic residues in the sequence are susceptible to photo-oxidation. Inventory records that note arrival date and storage location reduce the chance of using degraded material.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Cyclic heptapeptide | Synthetic analogue of alpha-MSH |
| Molecular formula | C50H68N14O10 | Acetate salt form commonly reported |
| Molecular mass | ~1025 Da | Monoisotopic value near 1025.2 |
| Key structural motif | Lactam bridge | Asp side chain to Lys side chain |
| Solid appearance | White to off-white powder | Lyophilised and hygroscopic |
Identity and purity are usually established with reversed-phase high-performance liquid chromatography combined with mass spectrometry. A gradient of water and acetonitrile containing trifluoroacetic acid is a common mobile phase, and ultraviolet detection near 214 nanometres responds to the peptide backbone. Mass spectrometry confirms the expected molecular mass and helps reveal truncation or oxidation products. Purity is reported as a peak-area percentage, a figure that depends on the wavelength and gradient used, so values from different laboratories are not always directly comparable. Peptide mapping and amino acid analysis provide additional confirmation when required.
Regulatory status varies by jurisdiction, where approved prescription products, compounded preparations and research-grade material are treated as distinct categories with different documentation requirements. Suppliers of research material commonly issue a certificate of analysis listing purity, identity and sometimes endotoxin content. Independent verification by a third-party laboratory is often recommended because self-reported figures are difficult to check. Literature discussions usually state the source, purity and storage conditions of the material used, since these details affect reproducibility. Analysts note that a reported purity figure does not by itself describe biological activity.
PT-141 is the research designation for bremelanotide, a synthetic cyclic heptapeptide developed as a melanocortin receptor agonist. The peptide contains seven amino acids with an internal lactam bridge that constrains the backbone into a stable ring. Cyclisation of this kind improves resistance to enzymatic degradation relative to linear analogues. The compound was first explored for effects on melanin production, because several melanocortin receptors influence pigmentation. Its later association with sexual desire emerged from observations made during that early work, and the molecule became the subject of a separate development programme.
Bremelanotide is a moderately large peptide with a molecular mass near 1025 daltons. In lyophilised form it appears as a white to off-white powder and is freely soluble in water and other polar solvents. The intact lactam ring is essential for receptor affinity, while linearised fragments bind far more weakly. Solutions are sensitive to extremes of pH and to prolonged exposure to light and heat, so handling typically involves buffered conditions and cold storage. Its short plasma half-life reflects rapid distribution and clearance rather than chemical breakdown inside the vial.
Reverse-phase high-performance liquid chromatography is the standard method for assessing purity. Mass spectrometry confirms molecular identity and detects sequence variants or truncation products. Ultraviolet absorbance at 214 or 280 nm is used for quantification, with the choice depending on the peptide sequence. Method validation typically addresses linearity, limit of detection, and precision across a defined concentration range. Impurity profiling may also employ ion-exchange or size-exclusion chromatography, and these techniques complement one another.
Certificate of analysis documents usually report purity percentage, molecular weight, and appearance. Researchers verify identity by comparing observed and theoretical mass values. Chain-of-custody records and batch numbers help trace material from source to experiment. Independent verification of supplier claims is considered good practice when material identity is critical to a study. Records should include the storage history of each aliquot, and unexpected deviations in appearance or solubility warrant re-testing before use.
Lyophilized peptide material is generally stored at -20 °C or below to limit degradation, while reconstituted solutions are less stable and are typically kept refrigerated and protected from light. Repeated freeze-thaw cycles can accelerate aggregation and should be minimized. Stability for any specific lot depends on purity, moisture content, and packaging. Handling in a temperature-controlled environment reduces variability across replicates, and exposure to ambient humidity during weighing can introduce error. Aliquotting reduces the number of times a stock container is opened.
== Paleontology == The oldest known fossil of Conidae is from the lower Eocene, about 55 million years ago. Analysis of nucleotide sequences indicate that all living species of Conidae belong to one of two clades that diverged about 33 million years ago. One clade includes most of the species in the eastern Pacific and western Atlantic regions, which were connected by the Central American Seaway until the emergence of the Isthmus of Panama less than three million years ago. The other clade includes most of the species in the eastern Atlantic and Indo-Pacific regions, which were connected by the Neo-Tethys Sea until 21 to 24 million years ago.
Provides $40 million for the National Garden of American Heroes; Requires the FCC and NTIA to identify and auction 600 MHz of the electromagnetic spectrum between 1.3 and 10 GHz by 2034, potentially raising up to $85 billion; Reduces the $200 tax levied on the manufacture or transfer of firearm silencers and short-barreled rifles on the National Firearms Act to $0, effectively eliminating the tax levied on those items; Expands the Radiation Exposure Compensation Act to people affected by nuclear development and testing; and Repeals the international package de minimis entry privilege, which allowed shipments under $800 to enter the U.S. tariff-free. Eliminates penalties for noncompliance with Corporate Average Fuel Economy standards.
In the run-up to the election, TikTok removed over 134,000 fake accounts, almost 2 million fake followers, 1,173 accounts impersonating Moldovan officials and over 9,300 videos that violated rules on civic integrity, disinformation and AI content generation; prevented 2.9 million fake likes and 1.8 million fake follow requests, also blocking the creation of over 268,000 spam accounts; and dismantled five coordinated networks with at least 7,593 accounts that "promoted pro-Russian politicians and attempted to discredit the current government". Furthermore, TikTok developed an in-app Electoral Center in partnership with the Central Electoral Commission of Moldova and worked with Reuters and the STOP FALS! Moldovan organization to fight, identify and educate about disinformation.
=== Category:EC 1.8 (act on a sulfur group of donors) === Category:EC 1.8.1 (with NAD+ or NADP+ as acceptor) Glutathione reductase EC 1.8.1.7 Thioredoxin reductase EC 1.8.1.9 Category:EC 1.8.2 (with a cytochrome as acceptor) Category:EC 1.8.3 (with oxygen as acceptor) Sulfite oxidase EC 1.8.3.1 Category:EC 1.8.4 (with a disulfide as acceptor) Category:EC 1.8.5 (with a quinone or similar compound as acceptor) Category:EC 1.8.6 deleted, included in EC 2.5.1.18 Category:EC 1.8.7 (with an iron–sulfur protein as acceptor) Category:EC 1.8.98 (with other, known, acceptors) Category:EC 1.8.99 (with other acceptors)
== Dihydrogen bond == The hydrogen bond can be compared with the closely related dihydrogen bond, which is also an intermolecular bonding interaction involving hydrogen atoms. These structures have been known for some time, and well characterized by crystallography; however, an understanding of their relationship to the conventional hydrogen bond, ionic bond, and covalent bond remains unclear. Generally, the hydrogen bond is characterized by a proton acceptor that is a lone pair of electrons in nonmetallic atoms (most notably in the nitrogen, and chalcogen groups). In some cases, these proton acceptors may be pi-bonds or metal complexes. In the dihydrogen bond, however, a metal hydride serves as a proton acceptor, thus forming a hydrogen-hydrogen interaction. Neutron diffraction has shown that the molecular geometry of these complexes is similar to hydrogen bonds, in that the bond length is very adaptable to the metal complex/hydrogen donor system.
Sources: en.wikipedia.org
This acquisition increased the total number of 7-Eleven stores in the US and Canada to nearly 9800. Following the purchase, the Oklahoma 7-Elevens were fully integrated into national branding, marketing, and loyalty campaigns. In April 2021, 7-Eleven launched the "Take it to Eleven" ad campaign. The slogan was partially inspired by the chain's name, but also the term "up to eleven" made popular in the film This is Spinal Tap. The slogan was only for the main 7-Eleven brand and not A-Plus or Stripes. By summer 2021, the company had installed just a few electric vehicle charging stations, but announced plans to expand considerably, with a target of 250 DC fast-charging locations in the U.S. and Canada by the end of 2022, starting with four states (California, Colorado, Florida and Texas). Less than two years later, in mid-March 2023, 7-Eleven announced plans for 7Charge, "its new, proprietary EV charging network and app", promoting the Android and iOS mobile apps, which allow users to find 7-Eleven - and future Speedway and Stripes - charger locations and pay for charging. 7Charge locations offer CCS and CHAdeMO charging; Tesla drivers, and other vehicles using the (once-proprietary) NACS connector, can also charge, but require a user-supplied CCS adapter. In August 2022, 7-Eleven acquired Skipcart, a same-day and on-demand delivery platform. In early 2024, parent company Seven & i Holdings' CEO Ryuichi Isaka announced changes to the business model of US stores, placing the company's focus on fresh foods instead of a "[reliance] on gasoline and cigarettes".
Christianity and Islam had the highest number of adherents among the religious citizens. Eastern Christianity predominated among Christians, with Russia's traditional Russian Orthodox Church being the largest Christian denomination. About 90% of the Soviet Union's Muslims were Sunnis, with Shias being concentrated in the Azerbaijan SSR. Smaller groups included Roman Catholics, Jews, Buddhists, and a variety of Protestant denominations (especially Baptists and Lutherans). Religious influence had been strong in the Russian Empire. The Russian Orthodox Church enjoyed a privileged status as the church of the monarchy and took part in carrying out official state functions. The immediate period following the establishment of the Soviet state included a struggle against the Orthodox Church, which the revolutionaries considered an ally of the former ruling classes. In Soviet law, the 'freedom to hold religious services' was constitutionally guaranteed, although the ruling Communist Party regarded religion as incompatible with the Marxist spirit of scientific materialism. In practice, the Soviet system subscribed to a narrow interpretation of this right, and in fact used a range of official measures to discourage religion and curb the activities of religious groups. The 1918 Council of People's Commissars decree establishing the Russian SFSR as a secular state also decreed that 'the teaching of religion in all [places] where subjects of general instruction are taught, is forbidden.
=== Versus anaerobic exercise === Aerobic exercise and fitness can be contrasted with anaerobic exercise, of which strength training and short-distance running are the most salient examples. The two types of exercise differ by the duration and intensity of muscular contractions involved, as well as by how energy is generated within the muscle. Common kettlebell exercises combine aerobic and anaerobic aspects. Allowing 24 hours of recovery between aerobic and strength exercise leads to greater fitness. New research on the endocrine functions of contracting muscles has shown that both aerobic and anaerobic exercise promote the secretion of myokines, with attendant benefits including growth of new tissue, tissue repair, and various anti-inflammatory functions, which in turn reduce the risk of developing various inflammatory diseases. Myokine secretion in turn is dependent on the amount of muscle contracted, and the duration and intensity of contraction. As such, both types of exercise produce endocrine benefits. In almost all conditions, anaerobic exercise is accompanied by aerobic (in the presence of oxygen) exercises because the less efficient anaerobic metabolism must supplement the aerobic system due to energy demands that exceed the aerobic system's capacity. During anaerobic exercise, the body must generate energy through other processes than aerobic metabolism, including glycolysis paired with lactic acid fermentation, and the phosphocreatine system to generate energy in the form of ATP.
== Equipment == In using form-fill-seal packaging machines, the main function is to place the product in a flexible pouch suitable for the desired characteristics of the final product. These pouches can either be pre-formed or thermoformed. The food is introduced into the pouch, the composition of the headspace atmosphere is changed within the package; it is then heat sealed. These types of machines are typically called pillow-wrap, which horizontally or vertically form, fill and seal the product. Form-fill-seal packaging machines are usually used for large scale operations. In contrast, chamber machines are used for batch processes. A filled pre-formed wrap is filled with the product and introduced into a cavity. The cavity is closed and vacuum is then pulled on the chamber and the modified atmosphere is inserted as desired. Sealing of the package is done through heated sealing bars, and the product is then removed. This batch process is labor-intensive and thus requires a longer period of time; however, it is relatively cheaper than packaging machines which are automated. Additionally, snorkel machines are used to modify the atmosphere within a package after the food has been filled. The product is placed in the packaging material and positioned into the machine without the need of a chamber. A nozzle, which is the snorkel, is then inserted into the packaging material. It pulls a vacuum and then flushes the modified atmosphere into the package. The nozzle is removed and the package is heat sealed. This method is suitable for bulk and large operations.
Sources: en.wikipedia.org
Goodman impelled technical and procedural progress and popularized the open rhinoplasty approach. In 1987, Gunter reported the technical effectiveness of the open rhinoplasty approach for performing a secondary rhinoplasty; his improved techniques advanced the management of a failed nose surgery. In early 2021, it was reported that a trend that involved getting a rhinoplasty had emerged on the social media platform TikTok. The trend became known as the #NoseJobCheck trend and involved users of the platform posting videos that showed how their noses looked before and after their rhinoplasty surgeries, with a specific audio soundtracking the video. From October 2020 to January 2021, the #NoseJobCheck audio had been used in over 120,000 videos and videos with the #NoseJobCheck hashtag had accumulated over one billion views.
nicotinamide + Nomega-[(2'-phospho-ADP)-D-ribosyl]-protein-L-arginine Thus, the two substrates of this enzyme are NAD+ (or NADP+) and protein L-arginine, whereas its two products are nicotinamide and Nomega-(ADP-D-ribosyl)-protein-L-arginine (or Nomega-[(2'-phospho-ADP)-D-ribosyl]-protein-L-arginine, respectively). This enzyme belongs to the family of glycosyltransferases, specifically the pentosyltransferases. The systematic name of this enzyme class is NAD(P)+:protein-L-arginine ADP-D-ribosyltransferase. Other names in common use include ADP-ribosyltransferase, mono(ADP-ribosyl)transferase, NAD+:L-arginine ADP-D-ribosyltransferase, NAD(P)+-arginine ADP-ribosyltransferase, and NAD(P)+:L-arginine ADP-D-ribosyltransferase. At least five forms of the enzyme have been characterised to date, some of which are attached to the membrane via glycosylphosphatidylinositol (GPI) anchors, while others appear to be secreted. The enzymes contain ~250-300 residues, which encode putative signal sequences and carbohydrate attachment sites. In addition, the N- and C-termini are predominantly hydrophobic, a characteristic of GPI-anchored proteins.
This poses a real challenge for the translators because they have to render the meaning, i.e. find an equivalent, of a very specific, scientific term in the target language and frequently the narrator uses a more general name instead of a specific term and the translator has to rely on the image presented in the programme to understand which term is being discussed in order to transpose it in the target language accordingly. Additionally, translators of minorised languages often face another problem: some terms may not exist in the target language. In such cases, they have to create new terminology or consult specialists to find proper solutions. Also, sometimes the official nomenclature differs from the terminology used by actual specialists, which leaves the translator to decide between using the official vocabulary that can be found in the dictionary, or rather opting for spontaneous expressions used by real experts in real-life situations.
Sources: en.wikipedia.org
PT-141 was the development code used for bremelanotide during its preclinical and early clinical programme. The peptide is now generally referred to by its international nonproprietary name.
The two compounds share the same cyclic core and are both non-selective melanocortin agonists. They differ chiefly at the C-terminus, where bremelanotide carries a free carboxylic acid and melanotan II a terminal amide.
Receptor binding profiles are well characterised in vitro, but the downstream pathway linking MC4R activation to behavioural effects is not fully mapped. Several intermediate neural circuits have been proposed without definitive confirmation.
Cold storage at minus twenty degrees Celsius or below is typical, with desiccant and protection from light. The solid form is far more stable than any solution.