deamidation is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2026-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
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 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.
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.
Semaglutide is a synthetic peptide of thirty-one amino acids that shares roughly ninety-four percent sequence identity with human glucagon-like peptide-1. Two substitutions resist enzymatic cleavage by dipeptidyl peptidase-4, and a fatty diacid side chain attached through a linker promotes binding to serum albumin. That albumin binding slows renal clearance and extends the circulating half-life from minutes to approximately one week. The structural changes are well established in the published literature. Whether the same modifications affect receptor signalling bias in ways that matter clinically remains an open question.
| 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 |
Quality control for peptide material focuses on identity, purity, content and the profile of impurities. Common degradants include deamidated and oxidised forms, plus aggregates formed during storage or handling. Forced degradation studies under heat, light, acid and peroxide help define which conditions accelerate change and which analytical methods detect it. Limits for individual impurities are set by pharmacopoeial monographs or manufacturer specifications. How much a given impurity affects biological activity is often uncertain, and conclusions may depend on the assay used.
Solid peptide material is generally kept at reduced temperature to limit degradation. Short-term storage at 2 to 8 degrees Celsius is common, while longer archival storage at minus 20 degrees Celsius or below is typical for lyophilised powder. Vials should remain sealed and protected from light, because ultraviolet exposure can oxidise susceptible residues. Repeated freeze-thaw cycles are avoided, as they promote aggregation and loss of soluble material. Solutions are less stable than solids and are usually prepared close to the time of use.
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.
Handling guidance for research quantities calls for single-use aliquots, an inert atmosphere where practical, and avoidance of repeated freeze-thaw cycles that accelerate aggregation. Certificates of analysis typically report purity by peak area, water content, counter-ion identity, and residual solvent levels. In the scientific literature the compound is usually described by its full amino acid sequence, its registry number, or its structural class rather than by any proprietary label. Reporting standards vary between journals, and reviewers increasingly request raw chromatograms alongside tabulated purity figures. Whether current purity thresholds are adequate for every experimental context is debated.
Reversed-phase high-performance liquid chromatography with ultraviolet detection is the dominant approach for peptide purity assessment, usually paired with mass spectrometry to confirm molecular mass and sequence. Peptide mapping by enzymatic digestion and tandem mass spectrometry locates modifications such as deamidation and oxidation. Quantitation in plasma matrices can be performed by LC-MS/MS after solid-phase extraction. Method validation follows general guidance on accuracy, precision, linearity, and limits of detection. Comparability of results between laboratories, when no shared reference standard is available, remains an open question.
Stability studies focus on deamidation of asparagine and glutamine residues, oxidation of methionine, and aggregation into higher-order species. The fatty acid side chain adds susceptibility to oxidative change and can promote self-association at high concentration. Lyophilised material is comparatively robust when kept cold and dry, while aqueous solutions require refrigeration and protection from light. Forced degradation experiments under heat, acid, base, and peroxide conditions establish the specificity of each analytical method. Which degradation route dominates under real storage conditions depends on the formulation and stays formulation-specific.
=== BBC === In September 2013, Willis was confirmed as the replacement for Holly Willoughby on the BBC One talent show The Voice UK. On 11 January 2014, she began co-presenting the third series with JLS singer Marvin Humes, who replaced Reggie Yates. In March 2014, it was announced that The Voice UK had been renewed for two future series. Both Willis and Humes returned to the show for the fourth series in 2015 and fifth series in 2016. In 2017, the show moved to ITV. Willis and Reggie Yates co-hosted the Saturday night game show Prized Apart on BBC One. The series began on 13 June 2015 and was axed after the first series, due to poor ratings. In May 2026, it was announced that Willis would become one of the new hosts of Strictly Come Dancing alongside Josh Widdicombe and Johannes Radebe replacing long-standing presenters Tess Daly and Claudia Winkleman.
== Applications == The products based on collagen proteins are used for food, health and nutrition, pharmaceutical industries and technical applications for example Photo, Ballistic, Restoration, Lubricants, Technical detergents.
Although the term was coined in the late 1980s one of the first retroactively recognized examples of a killer application is the VisiCalc spreadsheet, released in 1979 for the Apple II. Because it was not released for other computers for 12 months, people spent US$100 (equivalent to $400 in 2025) for the software first, then $2,000 to $10,000 (equivalent to $9,000 to $44,000) on the requisite Apple II. Byte wrote in 1980, "VisiCalc is the first program available on a microcomputer that has been responsible for sales of entire systems", and Creative Computing's VisiCalc review is subtitled "reason enough for owning a computer". Others also chose to develop software, such as EasyWriter, for the Apple II first because of its higher sales, helping Apple defeat rivals Commodore International and Tandy Corporation. The co-creator of WordStar, Seymour Rubinstein, argued that the honor of the first killer app should go to that popular word processor, given that it came out a year before VisiCalc and that it gave a reason for people to buy a computer. However, whereas WordStar could be considered an incremental improvement (albeit a large one) over smart typewriters like the IBM Electronic Selectric Composer, VisiCalc, with its ability to instantly recalculate rows and columns, introduced an entirely new paradigm and capability unavailable on larger computers. Lotus 1-2-3 similarly benefited sales of the IBM PC. Noting that computer purchasers did not want PC compatibility as much as compatibility with certain PC software, InfoWorld suggested "let's tell it like it is.
Darglitazone (previously known as CP 86325-2) is a member of the thiazolidinedione class of drugs and an agonist of peroxisome proliferator-activated receptor-γ (PPAR-γ), an orphan member of the nuclear receptor superfamily of transcription factors. It has a variety of insulin-sensitizing effects, such as improving glycemic and lipidemic control, and was studied by Pfizer as a potential treatment of metabolic disorders such as type 2 diabetes mellitus. Its development was terminated in 1999.
Sources: en.wikipedia.org
==== PET imaging ==== Similar to MRI imaging, metal radionuclides can be loaded into nanogels and crosslinked to obtain PET radiotracers for imaging. Nanogels containing copper isotopes commonly used for PET imaging demonstrated overall stability and accumulation in tumors, which produced a higher signal in comparison to nearby tissue. Other studies have explored similar technologies with redox-responsive nanogels loaded with an isotope of gallium and other trivalent metals for PET imaging. Nanogels composed of dextran have also been developed for imaging tumor-associated macrophages with radionuclides and targeting the bone.
While the exact end date of the Cold War is debated among historians, it is generally agreed upon that the implementation of nuclear and conventional arms control agreements, the withdrawal of Soviet military forces from Afghanistan and Eastern Europe, and the resultant collapse of the Soviet Union marked the end of the Cold War. Scholars remain divided over the underlying causes, with materialist accounts emphasizing Soviet economic decline and ideational accounts stressing the personal worldviews of Gorbachev and Reagan coupled with the broader appeal of the Western European model.
=== Alexandria Ship Project === In January 2016, a mid-18th century ship was discovered on the waterfront of Alexandria, Virginia. Conservation efforts include keeping the wood submerged and wet since the wooden frame was waterlogged. The conservation of this ship is ongoing. When the waterlogged wooden frame was originally removed from the archaeological site, the timber frames were stored in fresh water vats until June 2017. The framed structure was then packaged and sent to the Conservation Research Laboratory at Texas A&M University for conservation. Documentation and conservation included laser scanning, modeling, X-ray, and wood degradation analysis before the treatment using polyethylene glycol and vacuum freeze drying
Funding for research into type 1 diabetes originates from the government, industry (e.g., pharmaceutical companies), and charitable organizations. Government funding in the United States is distributed via the National Institutes of Health, and in the UK via the National Institute for Health and Care Research or the Medical Research Council. The Juvenile Diabetes Research Foundation (JDRF), founded by parents of children with type 1 diabetes, is the world's largest provider of charity-based funding for type 1 diabetes research. Other charities include the American Diabetes Association, Diabetes UK, Diabetes Research and Wellness Foundation, Diabetes Australia, and the Canadian Diabetes Association.
Arrived in Europe in the 16th century, this solanaceous plant (with a pink skinned tuber in England and a yellow skin in Spain) spread in the Principality of Liege, Ireland, Flanders, Germany, Switzerland, Italy, Austria, etc. In France, its resemblance with toxic species (for example the daturas, known for their toxicity to livestock, but also to humans) and the lack of techniques of conservation and use, are brakes to its cultivation, beside purely agronomic reasons (bad ecological adaptation) or religious (non-perception of the tithe on this food). In the Théâtre d'agriculture et Mesnage des champs, published in 1600, Olivier de Serres already recommended the cultivation of the "white truffle" or "cartoufle" and found it to have a flavor worthy of the best black truffles. Around 1750, the cultivation and consumption of tubers were recommended by several people or institutions: Duhamel du Monceau, the bishops of Albi and Léon, the minister Turgot, Rose Bertin, the Agricultural Society of Rennes. Ten years before the publications of Antoine Parmentier and Samuel Engel, Duhamel du Monceau "strongly exhorts farmers not to neglect the cultivation of this plant" and remarks that "it is an excellent food especially with a little bacon and salted pork". But the French population remains more than reticent before this dish: the majority of French people still disdain it as a food for humans, even if it is cultivated and used in some regions.
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.
It is a glucagon-like peptide-1 receptor agonist, often grouped with the incretin mimetics. Its backbone is modified from the human hormone to resist enzymatic degradation and to bind albumin. These two features distinguish it from the native peptide.