If you have been reading about peptide analogue and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2025-11-17. Where a claim depends on a specific study, the study is described rather than over-claimed.
Semaglutide is a synthetic peptide analog of human glucagon-like peptide-1, a gut hormone released after meals. Its backbone retains the GLP-1 sequence but incorporates two substitutions that slow enzymatic breakdown by dipeptidyl peptidase-4. A short polyethylene glycol linker and a C18 fatty diacid are attached to the peptide chain, allowing the molecule to bind serum albumin and remain in circulation far longer than the native hormone. The result is a circulating half-life measured in days rather than the minutes typical of endogenous GLP-1.
Receptor activation occurs at GLP-1 receptors distributed across pancreatic islets, the hypothalamus, and the gastrointestinal tract. Binding triggers G protein signaling that raises cyclic AMP and enhances glucose-dependent insulin release. Because the effect depends on prevailing glucose levels, insulin secretion does not rise when blood sugar is already low. Signaling in the brain and gut also influences appetite and gastric emptying, which is why the compound appears in both metabolic and weight-related research literature.
Development began in the early 2010s with the goal of extending GLP-1 activity beyond the brief window achieved by native peptide infusion. The earliest approved formulation was a subcutaneous injection given once weekly. A later oral tablet pairs the peptide with an absorption enhancer, sodium N-(8-[2-hydroxybenzoyl] amino) caprylate, usually shortened to SNAC. That carrier lowers local pH and helps the peptide cross gastric tissue. Both routes deliver the same active molecule.
Semaglutide 是一种经结构修饰的胰高血糖素样肽-1 类似物，其主链与内源性 GLP-1(7-36) 约有百分之九十四的序列一致性。第 8 位丙氨酸被 α-氨基异丁酸取代，使二肽基肽酶-4 无法识别原有切割位点。第 34 位赖氨酸换为精氨酸，进一步降低酶解速率。第 26 位赖氨酸经间隔基连接一条含十八个碳的二酸脂肪链，该侧链赋予分子与血浆白蛋白结合的能力。
该分子作为 GLP-1 受体的选择性激动剂发挥作用，受体属于 B 类 G 蛋白偶联受体家族，激活后经 Gs 通路提升细胞内环腺苷酸水平。在胰腺 β 细胞，信号促进葡萄糖依赖性的胰岛素释放，血糖偏低时该作用明显减弱。在胰岛 α 细胞，胰高血糖素分泌受到抑制。中枢神经系统与胃肠道同样存在受体表达，相应信号参与食欲调节以及胃排空速率的降低。
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic peptide, GLP-1 receptor agonist | Not a small molecule |
| Backbone substitutions | Non-natural residue at position 8, arginine at position 34 | Slows enzymatic cleavage |
| Side chain | C18 fatty diacid with PEG linker | Enables albumin binding |
| Approximate molecular mass | 4114 Da | Varies slightly with salt form |
| Reported half-life | About one week | Longer than native GLP-1 by orders of magnitude |
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 nm is the standard purity method, reported as area percent. Mass spectrometry, usually with electrospray ionisation, confirms identity and reveals covalent modifications. Size-exclusion chromatography quantifies aggregates and fragments. Peptide mapping after enzymatic digestion localises changes to specific sequence regions. Circular dichroism and infrared spectroscopy report on secondary structure, while light scattering tracks particle formation in liquid formulations. No single technique captures every quality attribute.
Quality control relies on pharmacopoeial monographs where they exist, combined with in-house specifications for identity, purity, water content, and counter-ion composition. Reference standards allow calibration across laboratories, although certified materials for every analogue are not universally obtainable. Batch records, chromatograms, and mass spectra form the documentation trail. Regulatory classification varies by jurisdiction and intended use, and research-grade material differs from pharmaceutical-grade material in testing scope. Analytical uncertainty is often expressed as relative standard deviation across replicate injections.
Lyophilised semaglutide is generally held at -20 °C or below, protected from light and moisture. Reconstituted solutions are typically kept at 2-8 °C and used within a defined window because degradation accumulates over time. Repeated freeze-thaw cycles are discouraged, since each cycle can promote aggregation and reduce monomeric content. Room-temperature stability of the solid has been examined in some studies but remains incompletely characterised for long durations, so cold storage is the conservative default for research material.
Pharmacological activity arises from agonism at the glucagon-like peptide-1 receptor, a G protein-coupled receptor expressed in the pancreas, the gastrointestinal tract, and the brainstem. Receptor activation raises intracellular cyclic adenosine monophosphate and enhances insulin release in a glucose-dependent manner, an effect that diminishes when blood glucose concentration is low. Other effects include slowed gastric emptying and hypothalamic satiety signalling. These pathways are described well. Receptor desensitisation rates across tissues, relative to the endogenous hormone, are still under investigation, and reported findings differ between laboratories.
The company that developed the compound filed it as a long-acting analogue, and it gained first approval in 2017 for type 2 diabetes. Later authorisations from several regulators extended the indication to chronic weight management, and the World Health Organization added the glucagon-like peptide-1 receptor agonist drug class to its model list of essential medicines in 2023. Production uses solid-phase peptide synthesis followed by side-chain conjugation and chromatographic purification. Supply constraints and cost differences across regions are well documented. Literature on long-term outcomes continues to grow, with many trials reporting surrogate endpoints rather than hard clinical endpoints.
Reconstituted solutions are less stable than the dry powder, and stability depends on concentration, pH, buffer composition, and container material. Low-protein-binding tubes reduce loss of peptide to plastic surfaces. Some researchers add a carrier protein to limit adsorption at low concentrations. The exact shelf life of a given solution is best determined empirically through a stability study rather than assumed from general guidance, because published data cover only a limited set of conditions.
Storage conditions for semaglutide depend heavily on the presentation. Lyophilized research powder is generally kept at two to eight degrees Celsius in a sealed container, protected from light and moisture. Manufacturer labeling for finished injectable products specifies refrigeration before first use, with defined in-use periods at room temperature afterward. The oral tablet form is stored at controlled room temperature and is more tolerant of short excursions. Temperature excursions should be documented rather than inferred.
Portable water purification devices are self-contained, easily transported units used to purify water from untreated sources (such as rivers, lakes, and wells) for drinking purposes. Their main function is to eliminate pathogens, and often also suspended solids and some unpalatable or toxic compounds. These units provide an autonomous supply of drinking water to people without access to clean water supply services, including inhabitants of developing countries and disaster areas, military personnel, campers, hikers, and workers in wilderness, and survivalists. They are also called point-of-use water treatment systems and field water disinfection techniques. Techniques include heat (including boiling), filtration, activated charcoal adsorption, chemical disinfection (e.g. chlorination, iodine, ozonation, etc.), ultraviolet purification (including sodis), distillation (including solar distillation), and flocculation. Often these are used in combination.
Territories on both sides of the new Polish-Ukrainian border were also "ethnically cleansed". Of the Ukrainians and Lemkos living in Poland within the new borders (about 700,000), close to 95% were forcibly moved to the Soviet Ukraine, or (in 1947) to the new territories in northern and western Poland under Operation Vistula. In Volhynia, 98% of the Polish pre-war population was either killed or expelled; in Eastern Galicia, the Polish population was reduced by 92%. According to Timothy D. Snyder, about 70,000 Poles and about 20,000 Ukrainians were killed in the ethnic violence that occurred in the 1940s, both during and after the war. According to an estimate by historian Jan Grabowski, about 50,000 of the 250,000 Polish Jews who escaped the Nazis during the liquidation of ghettos survived without leaving Poland (the remainder perished). More were repatriated from the Soviet Union and elsewhere, and the February 1946 population census showed about 300,000 Jews within Poland's new borders.[e] Of the surviving Jews, many chose to emigrate or felt compelled to because of the anti-Jewish violence in Poland. Because of changing borders and the mass movements of people of various nationalities, the emerging communist Poland ended up with a mainly homogeneous, ethnically Polish population (97.6% according to the December 1950 census). The remaining members of ethnic minorities were not encouraged, by the authorities or by their neighbors, to emphasize their ethnic identities.[i][a1]
The two basic categories of tequila are mixtos and 100% agave. Mixtos use no less than 51% agave, with other sugars making up the remainder. Mixtos use both glucose and fructose sugars. There are five categories of tequila defined by the NOM:
Affected children, who seem healthy initially, may experience symptoms like low blood sugar without ketones (hypoketotic hypoglycemia) and vomiting Can escalate to lethargy, seizures and coma, typically triggered by illness Acute episodes may also involve enlarged liver (hepatomegaly) and liver issues Sudden death Treatments
Sources: en.wikipedia.org
== External links == Mercaptans (or Thiols) at The Periodic Table of Videos (University of Nottingham) Applications, Properties, and Synthesis of ω-Functionalized n-Alkanethiols and Disulfides – the Building Blocks of Self-Assembled Monolayers by D. Witt, R. Klajn, P. Barski, B.A. Grzybowski at Northwestern University. Mercaptan, by The Columbia Electronic Encyclopedia What is Mercaptan? Archived 2008-12-20 at the Wayback Machine, by Columbia Gas of Pennsylvania and Maryland. What Is the Worst Smelling Chemical? Archived 2011-06-06 at the Wayback Machine, by About Chemistry.
=== Casein allergy === A small fraction of the population is allergic to casein. Casein intolerance, also known as "milk protein intolerance", is experienced when the body cannot break down the proteins of casein. The prevalence of casein allergy or intolerance ranges from 0.25% to 4.9% of young children. Numbers for older children and adults are not known. Casein that is heat-treated has been shown to be more allergenic and harder to digest when fed to infants. Breast milk has not been shown to cause an allergic reaction typically, but should be administered to an infant with caution each time in case of adverse reaction from something the breastfeeding parent consumed that contained casein. Following a casein-free diet has been shown to improve outcomes of infants who are breastfed while allergic or intolerant to dairy protein. Supplementation of protease enzyme has been shown to help casein intolerant individuals digest the protein with minimal adverse reaction.
On December 15, 2020, the acquisition was completed, and Dunkin' Brands ceased to exist as a separate company, with Dunkin', Baskin-Robbins, and the trademark management of Mister Donut, becoming part of Inspire Brands. In May 2026, Dunkin' current parent company Inspire Brands signed a franchise agreement with Montreal-based holding company Foodtastic to bring the restaurant chain back to Canada eight years after the company ceased its operations in the North. Peter Mammas, the president and CEO of restaurant holding company Foodtastic said its return this time will be different, and that this time the chain’s focus will be on Canadian ownership. Mammas expects the first Dunkin’ cafes to open in Canada later this year. A year from now, he says the company will likely be able to open a cafe a week, and about 50 cafes a year. “We have boots on the ground, so we’re going to have local support to support the franchises,” he said. He also said the company will concentrate on opening stores in Quebec and Ontario for the first two years before opening cafes in the Maritimes and the West Coast.
Although statistics of the Soviet economy are notoriously unreliable and its economic growth difficult to estimate precisely, by most accounts, the economy continued to expand until the mid-1980s. During the 1950s and 1960s, it had comparatively high growth and was catching up to the West. However, after 1970, the growth, while still positive, steadily declined much more quickly and consistently than in other countries, despite a rapid increase in the capital stock (the rate of capital increase was only surpassed by Japan). Professor of Economic History Bob Allen contends that in the era in which the Soviet economy was publicly owned and planned (1928–1989), the Soviet Union's GDP per capita growth outpaced nearly all other world economies, trailing only Japan, South Korea, and Taiwan. Data shows that Soviet per capita growth expanded by a factor of 5.2, exceeding the growth rates of Western Europe at 4.0, and the US, Canada, Australia, and New Zealand at 3.3. Ultimately, the Soviet model of public ownership proved more effective at raising average incomes during this period than the world's primary industrialized capitalist systems. Scholar Christopher Davidson argued that, during the 1980s, the Reagan administration attempted to weaponize the global energy market against the USSR. At the request of CIA Director William J. Casey, Saudi Arabia flooded the market with oil, dropping the price from $28 to $10 per barrel, and draining Soviet foreign currency reserves. This was later described by a former CIA chief of staff as a "body blow to the Soviets.
Anima and animus—(archetype) the contrasexual aspect of a person's psyche. In a woman's psyche, her inner personal masculine is conceived as a complex and an archetypal image; in a man's psyche, his inner personal feminine is conceived both as a complex and an archetypal image. Archetype—a concept "borrowed" from anthropology to denote supposedly universal and recurring mental images or themes. Jung's descriptions of archetypes varied over time. Archetypal images—universal symbols that mediate opposites in the psyche, often found in religious art, mythology, and fairy tales across cultures. Collective unconscious—aspects of unconsciousness experienced by all people in different cultures. Complex—the repressed organisation of images and experiences that governs perception and behaviour. Extraversion and introversion—personality traits of degrees of openness or reserve contributing to psychological type. Individuation—the process of fulfilment of each individual "which negates neither the conscious or [sic] unconscious position but does justice to them both". Interpersonal relationship—the way people relate to others reflects how they relate to themselves. This may also be extended to relations with the natural environment. Numinous—a healing, transformative or destructive spiritual power. Also, an invisible power inherent in an object. Jung develops the concept from the work of Rudolf Otto, who based it on the Latin numen. Persona—element of the personality that arises "for reasons of adaptation or personal convenience"—the "masks" one puts on in various situations.
Sources: en.wikipedia.org
== Awards received while alive == In 1919, she was awarded the Notable Service Medal by President Herbert Hoover for her work in refrigeration. In 1940, she became the second recipient of the Garvan–Olin Medal, then called the Francis P. Garvan Medal, from the American Chemical Society.
or greater and depend on impurity concentration. Near zero carrier density, graphene exhibits positive photoconductivity and negative photoconductivity at high carrier density, governed by the interplay between photoinduced changes of both the Drude weight and the carrier scattering rate. Graphene doped with various gaseous species (both acceptors and donors) can be returned to an undoped state by gentle heating in a vacuum. Even for dopant concentrations in excess of 1012 cm−2, carrier mobility exhibits no observable change. Graphene doped with potassium in ultra-high vacuum at low temperature can reduce mobility 20-fold. The mobility reduction is reversible on heating the graphene to remove the potassium. Due to graphene's two dimensions, charge fractionalization (where the apparent charge of individual pseudoparticles in low-dimensional systems is less than a single quantum) is thought to occur. It may therefore be a suitable material for constructing quantum computers using anyonic circuits.
=== Normal === In healthy adults, the normal concentrations of CRP varies between 0.8 mg/L and 3.0 mg/L. However, some healthy adults show elevated CRP at 10 mg/L. CRP concentrations also increase with age, possibly due to subclinical conditions. Additionally, there are seasonal variations of CRP concentrations, with highest levels occurring in the winter. Gene polymorphism of interleukin-1 family, interleukin 6, and polymorphic GT repeat of the CRP gene do affect the usual CRP concentrations when a person does not have any medical illnesses.
One mode of monazite formation is crystallization from an igneous melt. The concentric zoning pattern reflects the changing composition of the melt which affects the composition of the crystallizing monazite.
Sources: en.wikipedia.org
Native GLP-1 is degraded within minutes by circulating enzymes. The synthetic version carries substitutions at positions that block enzymatic cleavage, plus a fatty acid side chain that promotes albumin binding. These two changes together extend circulation time from minutes to roughly a week.
Albumin binding keeps a large fraction of the compound in a slowly released reservoir within the bloodstream. Plasma levels decline gradually rather than falling sharply after each administration. That profile supports dosing intervals measured in days instead of hours.
The active peptide sequence is the same in both formats. The oral version adds an absorption enhancer that is not present in the injected solution. Differences in excipients and formulation affect uptake rather than the identity of the active molecule.
差别集中在三处：第 8 位残基被非天然氨基酸取代，第 34 位换成精氨酸，第 26 位增加一条脂肪酸侧链。前两处改动降低酶解速率，侧链则通过白蛋白结合延长循环时间。综合结果是半衰期从约两分钟延长到约一周。