This is a working overview of deamidation, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-06-21. Anything still debated is marked as such rather than presented as settled.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular class | 31-amino-acid peptide | Modified glucagon-like peptide-1 analogue |
| Molecular mass | approximately 4114 Da | Calculated for the free peptide backbone |
| Appearance | white to off-white powder | Typical of purified lyophilised peptide batches |
| Solubility class | freely soluble in water | Aqueous solubility improves at slightly alkaline pH |
| Typical storage | -20 degrees Celsius, dry, dark | Protect from repeated freeze-thaw cycles |
Serum protein binding dominates the pharmacokinetic profile. The attached chain associates strongly with albumin, shielding the peptide from enzymatic attack and slowing filtration by the kidney. This interaction extends the circulation half-life to roughly one week in humans, which supports weekly administration intervals. An oral version pairs the peptide with an absorption enhancer that transiently alters gastric epithelium, permitting limited uptake; bioavailability by that route is substantially lower than by injection.
Semaglutide belongs to the glucagon-like peptide-1 receptor agonist class, a group of synthetic peptides that imitate an incretin hormone released by intestinal L cells after food intake. Native GLP-1 circulates for only a few minutes because dipeptidyl peptidase-4 cleaves it rapidly. The hormone acts on pancreatic islets, the gastrointestinal tract, and several brain regions. Because the natural peptide is short-lived, development work concentrated on analogues that keep receptor activity while resisting enzymatic breakdown and renal clearance.
The semaglutide sequence is a 31-residue analogue of human GLP-1, altered at three positions relative to the parent hormone. Aminoisobutyric acid replaces alanine at position 8, arginine replaces lysine at position 34, and a lipophilic diacid is attached to lysine 26 through a short linker. These features are reported consistently in the structural literature. The position 8 substitution blocks recognition by dipeptidyl peptidase-4, while the attached chain drives strong, reversible association with a carrier protein in blood.
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.
The primary target is the GLP-1 receptor, a class B G protein-coupled receptor expressed on pancreatic beta cells, in the gut, and in several brain regions. Receptor activation raises intracellular cyclic AMP, which potentiates glucose-dependent insulin secretion and lowers glucagon release when blood glucose is elevated. Signalling in the hypothalamus and brainstem is associated with reduced appetite and slower gastric emptying. Because the insulinotropic effect depends on prevailing glucose levels, the hypoglycaemic risk of the peptide alone is described as low in most study settings. The relative contribution of peripheral and central actions remains an active research question.
=== Catabolism === Isoleucine is both a glucogenic and a ketogenic amino acid. After transamination with alpha-ketoglutarate, the carbon skeleton is oxidised and split into propionyl-CoA and acetyl-CoA. Propionyl-CoA is converted into succinyl-CoA, a TCA cycle intermediate which can be converted into oxaloacetate for gluconeogenesis (hence glucogenic). In mammals acetyl-CoA cannot be converted to carbohydrate but can be either fed into the TCA cycle by condensing with oxaloacetate to form citrate or used in the synthesis of ketone bodies (hence ketogenic) or fatty acids.
== Background == Chinese Communist Party general secretary Xi Jinping and United States president Donald Trump held their first meeting during Trump's second presidency at the Busan Summit on 30 October 2025. At the meeting, Trump announced plans to visit China in April of the following year and invited Xi to visit the United States at an appropriate time. The state visit was planned for the first week of April, but the meeting was postponed to May due to the 2026 Iran war. On 25 March, The White House announced Trump's visit would last from 12 to 15 May. In the lead-up to the summit, regional security concerns regarding the conflict with Iran became a key diplomatic focus. On 16 April, Defense Secretary Pete Hegseth announced that Beijing had provided high-level assurances to the White House that it would not send weapons to Iran, explicitly ruling out the potential transfer of surface-to-air missiles to the Iranian military. Hegseth attributed this breakthrough to the "strong and direct relationship" between President Trump and Xi Jinping, noting that the assurances were vital for the upcoming meeting in Beijing. U.S. secretary of state Marco Rubio met on 13 February with Wang Yi, director of the Office of the Central Foreign Affairs Commission and foreign minister. The two sides discussed President Donald Trump's planned visit to China. On 30 April, Wang held a phone call with Rubio to conduct preliminary communication regarding subsequent head-of-state diplomacy. Steve Daines led the first bipartisan U.S.
=== Linear Pottery Culture === Ceramic Petrography has been used extensively in the study of the Linear Pottery Culture (LBK), a European Neolithic culture dating to around 5550 BCE – 4500 BCE. Petrographic analysis has allowed archaeologists to classify LBK ceramics and establish chronological sequences. It has also allowed archaeologists to source raw materials, understand trade routes, and analyse the various production methods. By examining the mineralogical composition and microstructure of LBK pottery, researchers have identified geological sources of raw materials, revealing procurement strategies and exchange networks. Additionally, petrographic analysis has provided insights into pottery manufacturing, including clay selection, forming techniques, surface treatments, and firing methods, contributing to our understanding of technological advancements and cultural practices. Through ceramic petrography, archaeologists can now understand far more about this culture, even with limited material to work with. Indeed, ceramic petrography has shed light on LBK typology, chronology, raw material procurement, trade networks, and technological innovations within the broader context of Neolithic Europe.
== Target and events == The primary target of the doctrine was originally the largest communist country, the Soviet Union. However, additional targets also included the other communist countries like the China, Laos, Vietnam, and North Korea. After the dissolution of the Soviet Union in 1991 and China's economic prominence in the early 21st century, China became the major target of the doctrine.
It was during this time period that President Roosevelt made his first visit to Mexico in April 1943, in what was an exchange visit, as President Ávila Camacho was also visiting the US. Both met in the city of Monterrey, specifically at the Palacio de Gobierno, and one of the topics covered there was Mexican participation in the war. These meetings demonstrated that never before had such a close and positive bilateral relationship been formed between the two countries, thus resolving an era of hostility that began a century ago.
Sources: en.wikipedia.org
The enterprise viewpoint, which focuses on the purpose, scope and policies for the system. It describes the business requirements and how to meet them. The information viewpoint, which focuses on the semantics of the information and the information processing performed. It describes the information managed by the system and the structure and content type of the supporting data. The computational viewpoint, which enables distribution through functional decomposition on the system into objects which interact at interfaces. It describes the functionality provided by the system and its functional decomposition. The engineering viewpoint, which focuses on the mechanisms and functions required to support distributed interactions between objects in the system. It describes the distribution of processing performed by the system to manage the information and provide the functionality. The technology viewpoint, which focuses on the choice of technology of the system. It describes the technologies chosen to provide the processing, functionality and presentation of information.
==== Stepwise coupling and coding ==== One of the most forward-looking method commonly used for DNA-encoding is applied in the synthesis of single-pharmacophore libraries. As the figure shows the library is built repeating the usual cycles of S&P synthesis, The second operation of the cycle is modified: in addition to coupling with the BBs the encoding DNA oligomer is elongated by attaching the code of the BB by ligation.
Attempting to quit "cold turkey" may result in neurological damage due to excitotoxicity, severe physical injuries received during convulsions, and even death resulting from arrhythmias during grande Mal seizures, paralleling death caused by delirium tremens.
Overall, 24 out of 25 patients treated with brentuximab vedotin and AVD achieved complete remission. Brentuximab vedotin is also being investigated as a substitute for vincristine (another mitotic inhibitor which prevents tubulin polymerization) in patients with being treated with CHOP (a combination of cyclophosphamide, hydroxydaunorubicin, vincristine, prednisone or prednisolone) for a non-Hodgkin lymphoma. A phase III clinical trial comparing the two combination therapies (CHOP and CHP-brentuximab vedotin) was completed in October 2020, with results published in 2021. The ECHELON-1 phase 3 trial compared brentuximab vedotin with bleomycin both in combination with adriamycin, vinblastine, dacarbazine (AVD) chemotherapy as a firstline treatment for advanced classical Hodgkin lymphoma. The outcome of the trial resulted in a positive recommendation by the Committee for Medicinal Products for Human Use (CHMP) as part of a combination treatment in adults with previously untreated CD30+ stage 3 Hodgkin lymphoma.
4-Hydroxyphenylpyruvic acid (4-HPPA) is an intermediate in the metabolism of the amino acid phenylalanine. The aromatic side chain of phenylalanine is hydroxylated by the enzyme phenylalanine hydroxylase to form tyrosine. The conversion from tyrosine to 4-HPPA is in turn catalyzed by tyrosine aminotransferase. Additionally, 4-HPPA can be converted to homogentisic acid which is one of the precursors to ochronotic pigment. It is an intermediary compound in the biosynthesis of scytonemin.
Sources: en.wikipedia.org
The origin and usage of the term metalloid is convoluted. The name was popularized by Jöns Berzelius in the early 19th century, but he did not use it in the current meaning, but rather for a diverse group of nonmetal elements. James Apjohn's "Manual of Metalloids" published in 1864 divided all elements into either metals or metalloids. Since the mid-20th century it has been used to refer to intermediate or borderline chemical elements. The International Union of Pure and Applied Chemistry (IUPAC) previously recommended abandoning the term metalloid, and suggested using the term semimetal instead. Despite the recommendation, the term metalloid was increasingly used in the literature in 1970–2010, while semimetal remained less popular. Use of the term semimetal has more recently been discouraged by Atkins et al. as it has a more common meaning that refers to the electronic band structure of a substance rather than the overall classification of an element. The most recent IUPAC publications on nomenclature and terminology do not include any recommendations on the usage of the terms metalloid or semimetal.
== Coaching career == Immediately after Hird retired from playing football, there was much speculation as to whether he would be interested in a coaching role at a club in the AFL, but primarily at Essendon. After initially dodging questions about his future, Hird stated in August 2010 that "There's something in me, deep in my heart, that says at some point I want to coach Essendon". These words came as a surprise to many, including former premiership teammate Matthew Lloyd, who said that Hird had "changed his whole persona in regards to how he's answering his questions... Just in regards to saying, 'I'll coach one day. I want to coach Essendon one day'. Even those type of words, I haven't heard before." These comments by Hird, considered to be Essendon's "favourite son", furthered speculation towards the future of then-Essendon coach Matthew Knights. A rumour emerged following these comments suggesting that Hird was part of an unofficial agreement with the Essendon board to replace Matthew Knights for the 2011 AFL Season. However, two days after Hird's initial comments, he announced that he had changed his mind due to the intense division and speculation over Matthew Knights' future following Hird's initial comments. Hird stated that he was ruling himself out of coaching Essendon for at least three years.
Patients being treated for osteoporosis or non-malignant bone disease with oral bisphosphonates/quarterly or yearly infusions of intravenous bisphosphonates for >5 years Patients being treated for osteoporosis or non-malignant bone disease with bisphosphonates/denosumab for any length of time as well as being treated with systemic glucocorticoids Patients being treated with anti-resorptive/anti-angiogenic drugs/both as part of cancer management Previous MRONJ diagnosis "N.B. Patients who have taken bisphosphonate drugs at any time in the past and those who have taken denosumab in the last nine months are allocated to a risk group as if they are still taking the drug."
1936: The first all-steel reefers entered service. 1946: Two experimental aluminum-body refrigerator cars entered service on the PFE; an experimental reefer with a stainless-steel body was built for the SFRD. 1950: The U.S. refrigerator car roster dropped to 127,200. 1957: The last ice bunker refrigerator cars were built. 1958: The first mechanical reefers (using diesel-powered refrigeration units) entered revenue service. 1959: The flush, "plug" style sliding door was introduced as an option, providing a larger door to ease loading and unloading. The tight-fitting doors were better insulated, helping the car maintain a more even temperature. An early example is the DT&I XL-1 car by Evans. 1966: Japanese National Railways started operation of fish freight express trains by newly built "resa 10000" type refers. 1969: ACF constructed several experimental center flow hopper cars incorporating mechanical cooling systems and insulated cargo cells. The units were intended for shipping bulk perishables. 1971: The last ice-cooled reefers were retired. 1980: The U.S. refrigerator car roster dropped to 80,000. 1986: The last reefers in Japan were replaced by reefer containers. 1990s: The first cryogenically cooled reefers entered service. 2001: The number of refrigerator cars in the United States bottomed out at approximately 8,000. 2005: The number of reefers in the United States climbs to approximately 25,000, due to significant new refrigerator car orders. 2006: Railex launches 55-car unit train reefer service between the U.S. West Coast and New York.
=== Flash Joule heating === In 2019, flash Joule heating (transient high-temperature electrothermal heating) was discovered to be a method to synthesize turbostratic graphene in bulk powder form. The method involves electrothermally converting various carbon sources, such as carbon black, coal, and food waste into micron-scale flakes of graphene. More recent works demonstrated the use of mixed plastic waste, waste rubber tires, and pyrolysis ash as carbon feedstocks. The graphenization process is kinetically controlled, and the energy dose is chosen to preserve the carbon in its graphenic state (excessive energy input leads to subsequent graphitization through annealing).
Sources: en.wikipedia.org
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.
No. It shares high sequence identity but carries non-natural modifications that alter its stability and clearance. The naturally occurring hormone is broken down within minutes, while the synthetic analogue circulates far longer.
Attachment to serum albumin reduces renal filtration of the peptide and shields it from enzymatic breakdown. The consequence is a much longer interval between administrations than unmodified peptides allow. The precise contribution of binding affinity to overall duration is still being quantified.
Manufacturers commonly state multi-year stability when the powder is kept dry and frozen. Actual shelf life depends on residual moisture, vial sealing, and storage temperature. A re-test by chromatography is the only way to confirm remaining purity.