deamidation raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2025-09-16. Anything still debated is marked as such rather than presented as settled.
Receptor binding triggers G protein signaling that raises intracellular cyclic AMP in pancreatic beta cells. Insulin release follows in a glucose-dependent manner, so secretion increases when blood glucose is elevated and diminishes when it is not. The same signaling suppresses glucagon release from alpha cells and slows gastric emptying, which blunts the post-meal glucose rise. In the brain, receptor activation in regions such as the arcuate nucleus is associated with reduced appetite and lower energy intake. How much each of these effects contributes to overall weight change is not fully settled.
Two structural features account for the prolonged half-life of semaglutide. A modified amino acid at position 8 resists cleavage by dipeptidyl peptidase-4, the enzyme that rapidly degrades native GLP-1. A fatty diacid side chain binds serum albumin, which limits renal clearance and protects the peptide from enzymatic breakdown. These modifications yield a plasma half-life of approximately one week in humans, allowing once-weekly administration. The relationship between plasma concentration and clinical effect varies between individuals, and sources of that variability are still being characterized.
Quantification and purity assessment rely on separation methods coupled to optical or mass detection. Reversed-phase high-performance liquid chromatography resolves the intact peptide from related impurities and is the standard assay technique. Size-exclusion chromatography measures aggregates, while ion-exchange chromatography separates charge variants produced by deamidation. Mass spectrometry confirms identity and detects mass shifts of a few daltons. In biological matrices, liquid chromatography with tandem mass spectrometry is often used because immunoassays can cross-react with endogenous GLP-1 or with circulating fragments.
As a peptide, semaglutide is sensitive to conditions that break amide bonds or modify side chains. Deamidation of asparagine and glutamine residues, oxidation of methionine and tryptophan, and non-covalent aggregation are the main degradation routes described in published stability work. Rate depends strongly on pH, buffer species, ionic strength, temperature and exposure to light. Formulators therefore choose a defined solution pH and often add excipients such as phosphate buffer, propylene glycol and phenol, each of which plays a separate role in pH control, tonicity or preservation.
| Property | Value | Notes |
|---|---|---|
| Chemical class | GLP-1 receptor agonist peptide | Mimics endogenous incretin signaling |
| Molecular mass | Approximately 4114 Da | Modified 31-amino-acid backbone |
| Appearance | White to off-white powder | Typical of lyophilized peptide material |
| Solubility | Soluble in water | Behavior depends on salt form and buffer |
| Elimination half-life | About one week | Supported by albumin binding and protease resistance |
Large randomised trials in adults with type 2 diabetes and in adults with obesity have reported reductions in body weight and improvements in several cardiovascular risk markers. One outcome trial found a lower incidence of major adverse cardiovascular events in participants with diabetes and established cardiovascular disease. Gastrointestinal effects such as nausea and vomiting are the most frequently reported adverse events and often diminish over time. Changes in lean body mass during weight loss are an area of ongoing investigation. Effects in adolescents and in pregnancy are less well characterised, and current labelling advises against use during pregnancy.
Semaglutide is a synthetic peptide analogue of glucagon-like peptide-1, a gut hormone released after nutrient intake. The molecule contains 31 amino acid residues and differs from the native sequence at several positions. A non-natural residue at position eight resists the enzyme that normally truncates the hormone, while a lysine-linked fatty diacid side chain promotes binding to serum albumin. These two modifications extend the circulating half-life from minutes to roughly one week. The peptide is produced by solid-phase synthesis followed by selective acylation, and its identity and purity are confirmed by spectrometric and chromatographic techniques.
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.
Peptide degradation follows several routes. Hydrolysis cleaves the backbone at susceptible residues, oxidation targets methionine and tryptophan side chains, and aggregation produces higher-molecular-weight species that are difficult to reverse. Light exposure accelerates oxidation, which is why amber glass or opaque secondary packaging is common. Repeated freeze-thaw cycles promote aggregation and are best avoided. Stability-indicating methods detect these changes before they become visible.
Quality control for research material typically involves reversed-phase HPLC for purity and identity, mass spectrometry for molecular weight confirmation, and Karl Fischer titration for residual water content. Peptide content is often reported as the mass of actual peptide rather than total powder mass, since counterions and water contribute to the latter. A certificate of analysis should list the method used for each specification. Limits and acceptance criteria vary by supplier and by intended application.
Stability studies examine how temperature, pH, and moisture influence degradation rates over time. In aqueous solution, hydrolysis and deamidation accelerate as pH moves away from mildly acidic conditions. Light exposure and residual metal ions can also trigger oxidation of susceptible residues. Accelerated aging at elevated temperature is used to estimate shelf life, though extrapolation to room temperature carries uncertainty because individual degradation pathways do not always scale predictably.
Lyophilized semaglutide powder is typically held at minus twenty degrees Celsius for long-term storage. At that temperature, solid-state degradation reactions proceed slowly and the peptide remains intact for extended periods. Repeated freeze-thaw cycles are best avoided because they promote aggregation and can shift the proportion of monomeric peptide present. Working aliquots are often prepared so that each portion is thawed only once, and desiccant is placed inside the vial to limit moisture uptake.
=== Arabati Baba Teḱe controversy === In 2002, a group of armed members of the Islamic Religious Community of Macedonia (ICM), a Sunni group that is the legally recognized organisation which claims to represent all Muslims in North Macedonia, unlawfully entered the Bektashi Order's Arabati Baba Teḱe in an attempt to reclaim this tekke as a mosque although the facility has never functioned as such. Subsequently, the Bektashi Order of North Macedonia sued the government for failing to restore the tekke to the Bektashis, pursuant to a law passed in the early 1990s returning properties previously nationalized under the Yugoslav government. The law, however, deals with restitution to private citizens, rather than religious communities. The ICM claim to the tekke is based upon their contention to represent all Muslims in North Macedonia; and indeed, they are one of two Muslim organizations recognized by the government, both Sunni. The Bektashi community filed for recognition as a separate religious community with the Macedonian government in 1993, which has refused to recognize them.
January 23: Law granting an additional benefit to pregnant women already receiving allowances under the law of August 5, 1914. June 18: Law amending the law of April 7, 1915, authorizing the government to revoke naturalization decrees of former nationals of enemy countries: naturalized persons from a country at war with France can be stripped of French nationality, and this loss may extend to the wife and children depending on circumstances. July 27: Law establishing "Wards of the Nation"; women may hold positions in national and departmental offices. August 5: Law concerning breastfeeding in industrial and commercial establishments. October 1: Law on the repression of public drunkenness and regulation of drinking establishments; part of a campaign against clandestine prostitution by both women and men. Additionally, girls under 18 may no longer work in drinking establishments unless they are family members of the owner. 1919
In May 2023, Lula met with Cape Verde prime minister Ulisses Correia e Silva in Brasília. Correia e Silva said his country could play an important role in bringing Brazil closer to ECOWAS countries while Lula stated that "Brazil believes in a solidary, mutually beneficial South-South cooperation based on shared experiences" between countries with Africa being a top priority. Lula said that he intends to step up cooperation programmes with Cape Verde in education and agriculture areas and that he plans to visit at least two African countries in 2023, namely Cape Verde and South Africa, respectively for the 2023 CPLP Summit and the 15th BRICS summit. In July 2023, Lula visited Cape Verde and met with president José Maria Neves who greeted "Brazil's comeback to international forums". Lula said he wants to "recover the good and productive relations Brazil used to have with Africa", and expressed his desire to open more Brazilian embassies in African countries and to pay another visit to Cape Verde to attend to 2023 CPLP Summit.
==== Other drugs ==== Acamprosate (Alcomed; Aotal; calcium acetylhomotaurinate; Campral; Campral EC; NS-11; Regtect; Sobriol; Zulex) – various actions – alcoholism Baclofen (Baclocur) – GABAB receptor agonist – alcoholism Calcium carbimide (Temposil) – aldehyde dehydrogenase 2 (ALDH2) inhibitor – alcoholism Cyanamide – aldehyde dehydrogenase 2 (ALDH2) inhibitor – alcoholism Disulfiram (Antabuse, Antabus) – aldehyde dehydrogenase 2 (ALDH2) inhibitor – alcoholism Flumazenil (flumazepil; Anexate) – GABAA receptor negative allosteric modulator/benzodiazepine antidote – benzodiazepine overdose Lofexidine (BA-168; BritLofex; Lucemyra; MDL-14042; MDL-14042A; RMI-14042A) – α2-adrenergic receptor agonist – opioid-related disorders Sodium oxybate (Alcover; SMO immediate release formulation) – GABAB and GHB receptor agonist – alcoholism
Muscimol is said to have similar effects on sleep in rodents as the related experimental pharmaceutical drug gaboxadol (THIP). In humans, gaboxadol decreases sleep onset latency, increases sleep duration, increases slow wave sleep (SWS) and slow wave activity (SWA), and does not suppress REM sleep. The effects of muscimol and gaboxadol on sleep differ from those of widely used GABAA receptor positive allosteric modulators like benzodiazepines and Z-drugs, which can instead disrupt SWS and SWA despite improving sleep onset and duration. Although muscimol and gaboxadol have similar effects on sleep, muscimol has additionally been found to increase REM sleep unlike gaboxadol. Ibotenic acid, a prodrug of muscimol, is active at doses of approximately 20 to 100 mg orally in humans. About 10 to 20% of ibotenic acid is said to be converted into muscimol following decarboxylation. Substantial amounts of ibotenic acid are also rapidly excreted unchanged.
Sources: en.wikipedia.org
=== 22 January === German Foreign Minister Annalena Baerbock stated that Germany would not stand in the way if Poland or other countries provide Leopard 2 tanks. Russian state media reported that Russian forces advanced into Orikhiv and Huliaipole towns in Zaporizhzhia Oblast.
Each temperature cycle theoretically doubles the quantity of target sequence. Detection of sequence variations using PCR typically involves the design and use oligonucleotide reagents that amplify the variant of interest more efficiently than wildtype sequence. PCR is currently the most widely used method for detection of DNA sequences. The detection of the marker might use real time PCR, direct sequencing, microarray chips—prefabricated chips that test many markers at once, or MALDI-TOF The same principle applies to the proteome and the genome. High-throughput protein arrays can use complementary DNA or antibodies to bind and hence can detect many different proteins in parallel. Molecular diagnostic tests vary widely in sensitivity, turn around time, cost, coverage and regulatory approval. They also vary in the level of validation applied in the laboratories using them. Hence, robust local validation in accordance with the regulatory requirements and use of appropriate controls is required especially where the result may be used to inform a patient treatment decision. Benefits
=== United States === The Centers for Disease Control and Prevention (CDC) issued a health alert to report that between March 2013 and May 2013, 14 overdose deaths related to injected acetylfentanyl had occurred among intravenous drug users (ages between 19 and 57 years) in Rhode Island. After confirming five overdoses in one county, including a fatality, Pennsylvania asked coroners and medical examiners across the state to screen for acetylfentanyl. As a result of this investigation, Pennsylvania confirmed at least one acetylfentanyl overdose death and attributed at least 50 fatalities to either fentanyl or acetylfentanyl during the first half of 2013. In July 2015, the DEA informed about 52 confirmed fatalities involving acetylfentanyl in the United States between 2013 and 2015.
Natural killer cell (NK) therapies and CAR-NK cell approaches are also being explored, leveraging NK cells' innate ability to target tumor cells. Other strategies include cancer vaccines, which aim to provoke an immune response against tumor-associated antigens, and may be either preventive or therapeutic. Immunomodulatory agents such as cytokines (e.g., interleukin-2, interferon-alpha) and Bacillus Calmette-Guerin (BCG) are used to enhance immune activity or alter the tumor microenvironment. Oncolytic virus therapies, which employ engineered viruses to selectively kill cancer cells while promoting systemic immunity, are also under investigation. In 2018, American immunologist James P. Allison and Japanese immunologist Tasuku Honjo received the Nobel Prize in Physiology or Medicine for their discovery of cancer therapy by inhibition of negative immune regulation.
=== Death === The Culture has a relatively relaxed attitude towards death. Genetic manipulation and the continual benevolent surveillance of the Minds make natural or accidental death almost unknown. Advanced technology allows citizens to make backup copies of their personalities, allowing them to be resurrected in case of death. The form of that resurrection can be specified by the citizen, with personalities returning either in the same biological form, in an artificial form (see below), or even just within virtual reality. Some citizens choose to go into "storage" (a form of suspended animation) for long periods of time, out of boredom or curiosity about the future. Attitudes individual citizens have towards death are varied (and have varied throughout the Culture's history). While many, if not most, citizens make some use of backup technology, many others do not, preferring instead to risk death without the possibility of recovery (for example when engaging in extreme sports). These citizens are sometimes called "disposables", and are described in Look to Windward. Taking into account such accidents, voluntary euthanasia for emotional reasons, or choices like sublimation (abandoning physical reality), the average lifespan of humans is said in Excession to be around 350 to 400 years. Some citizens choose to forgo death altogether, although this is rarely done and is viewed as an eccentricity.
Sources: en.wikipedia.org
Little is known of the reproductive behavior of the white shark. There are two anecdotal accounts of the species possibly mating, one in 1991 and another in 1997, both off New Zealand. These testimonies both report belly-to-belly rolling during copulation. Researchers assume that the male bites onto the female's head or fin while inserting one of his claspers (sex organs), as is the case in other shark species. The accounts also suggest that white sharks mate in shallow water away from feeding areas. Females at Guadalupe and Cape Cod have been seen with scarring that may have been the result of copulation, possible evidence that these areas are used for mating. Conversely, other studies have concluded that white sharks may mate offshore; males off western North America were found to gather in the open ocean during spring and were followed by some females, suggesting a lek mating system where females move through and choose their partners. In 2013, it was proposed that whale carcasses are an important location for sexually mature sharks to meet for mating, especially with the frenzied excitement. Captures of pregnant females have provided key insights into the species's reproduction. The white shark is ovoviviparous; fertilized eggs hatch within the female, and the embryos continue to develop within each uterus. Their nourishment comes in three stages: they first feed on their yolk sacs, then a milky substance secreted by the uterus known as lipid histotrophy, and finally switch to consuming unfertilized eggs.
== Treatment == Treatment is normally azithromycin by oral tablets, or less commonly by a course of other antibiotics, such as benzathine benzylpenicillin, an alternative for patients where azithromycin treatment failed, or tetracycline tablets. Penicillin has been the front-line treatment since at least the 1960s, but there is no solid evidence of the evolution of penicillin resistance in yaws. The historical strategy for the eradication of yaws (1952–1964) was:
=== Early knowledge and study === Humans have had an observational relationship with birds since prehistory, with some stone-age drawings being amongst the oldest indications of an interest in birds. Birds were perhaps important as food sources, and bones of as many as 80 species have been found in excavations of early Stone Age settlements. Water bird and seabird remains have also been found in shell mounds on the island of Oronsay off the coast of Scotland.
First Reverse Aging Trial in Humans ° The biopharmeceutical company Life Biosciences, founded by David A. Sinclair, announced the start of a phase 1 clinical trial for ER-100, a novel therapy intended to reverse age-related vision loss via the activation of three genes in retinal ganglion cells, marking the first time a cellular reprogramming therapy was given to humans.
Sources: en.wikipedia.org
Native GLP-1 is degraded within minutes by dipeptidyl peptidase-4 and cleared quickly. Semaglutide carries a position 8 substitution that blocks that cleavage and a fatty diacid chain that binds albumin. Together these changes extend its circulating half-life to about one week.
Yes. Stimulation of insulin secretion is glucose-dependent, meaning the effect is larger when blood glucose is high and minimal when it is normal. This property separates GLP-1 receptor agonists from agents that drive insulin release regardless of glucose level.
Receptor expression in hypothalamic and brainstem regions is well documented, and reduced energy intake is consistently observed. The relative contribution of central versus peripheral signaling to total weight change is still an open question addressed by ongoing research.
Ice formation concentrates solutes and can mechanically stress the peptide or damage the delivery device. Thawing afterwards may leave aggregates that are not visible to the eye. Refrigeration keeps the solution above its freezing point while slowing chemical degradation.