deamidation comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2025-12-10. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Semaglutide is a synthetic peptide analog of glucagon-like peptide-1 (GLP-1), a hormone released from intestinal L-cells after food intake. The compound belongs to the incretin mimetic class and acts at GLP-1 receptors distributed across pancreatic, gastrointestinal, cardiovascular, and central nervous system tissues. Compared with native GLP-1, the molecule carries structural changes that extend its activity from minutes to roughly one week. It is studied for glycemic control in type 2 diabetes and for weight management, and its effects on cardiovascular and other outcomes remain active research areas.
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.
Storage guidance for the finished injectable product distinguishes the unused state from the in-use state. Before first use, pens are kept refrigerated between 2 and 8 degrees Celsius, protected from light, and never frozen, since freezing can disrupt the peptide or the device. After first use, label instructions in several markets permit storage at room temperature up to about 30 degrees Celsius for a limited number of days. Solid research-grade material is normally held at or below minus 20 degrees Celsius, often with desiccant, and allowed to equilibrate before opening.
| 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.
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.
Handling practices center on minimizing contamination and adsorption. Lyophilized peptide tends to accumulate static charge, so weighing is done with antistatic measures and calibrated balances. Reconstitution with appropriate solvent should be gentle, avoiding vigorous vortexing that generates foam and shear. Solutions are typically aliquoted before freezing to reduce repeated temperature cycling. Personal protective equipment and a fume hood are standard for powder handling.
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.
Junior became the foundation chairman in 1917. Through the Laura Spelman Rockefeller Memorial (LSRM), established by Senior in 1918 and named after his wife, the Rockefeller fortune was for the first time directed to supporting research by social scientists. During its first few years of work, the LSRM awarded funds primarily to social workers, with its funding decisions guided primarily by Junior. In 1922, Beardsley Ruml was hired to direct the LSRM, and he most decisively shifted the focus of Rockefeller philanthropy into the social sciences, stimulating the founding of university research centers, and creating the Social Science Research Council. In January 1929, LSRM funds were folded into the Rockefeller Foundation, in a major reorganization. The Rockefeller family helped lead the foundation in its early years, but later limited itself to one or two representatives, to maintain the foundation's independence and avoid charges of undue family influence. These representatives have included the former president John D. Rockefeller III, and then his son John D. Rockefeller, IV, who gave up the trusteeship in 1981. In 1989, David Rockefeller's daughter, Peggy Dulany, was appointed to the board for a five-year term. In October 2006, David Rockefeller Jr. joined the board of trustees, re-establishing the direct family link and becoming the sixth family member to serve on the board.
=== Dwarf sports === Dwarfs have support and compete in sport by a number of organizations nationally and internationally. They are included in some events in the athletics at the Summer Paralympics. The Dwarf Athletic Association of America and the Dwarf Sports Association UK provide opportunities for dwarfs to compete nationally and internationally in the Americas and Europe, respectively. The World Dwarf Games (WDG) are a multi-sport event for athletes of short stature. The WDG have been held every four years since 1993 and are the world's largest sporting event exclusively for athletes with dwarfism. The Dwarf Sports Association UK organizes between 5 and 20 events per month for athletes with restricted growth conditions in the UK. For instance, swimming and bicycling are often recommended for people with skeletal dysplasias, since those activities put minimal pressure on the spine. Since its early days, professional wrestling has had the involvement of dwarf athletes. "Midget wrestling" had its heyday in the 1950s–'70s, when wrestlers such as Little Beaver, Lord Littlebrook, and Fuzzy Cupid toured North America, and Sky Low Low was the first holder of the National Wrestling Alliance's World Midget Championship. In the next couple of decades, more wrestlers became prominent in North America including foreign wrestlers like Japan's Little Tokyo. Although the term is seen by some as pejorative, many past and current midget wrestlers including Hornswoggle said they take pride in the term due to its history in the industry and its marketability.
Most applications of NMR involve full NMR spectra, that is, the intensity of the NMR signal as a function of frequency. Early attempts to acquire the NMR spectrum more efficiently than simple CW methods involved illuminating the target simultaneously with more than one frequency. A revolution in NMR occurred when short radio-frequency pulses began to be used, with a frequency centered at the middle of the NMR spectrum. In simple terms, a short pulse of a given "carrier" frequency "contains" a range of frequencies centered about the carrier frequency, with the range of excitation (bandwidth) being inversely proportional to the pulse duration, i.e. the Fourier transform of a short pulse contains contributions from all the frequencies in the neighborhood of the principal frequency. The restricted range of the NMR frequencies for most light spin-1/2 nuclei made it relatively easy to use short (1 - 100 microsecond) radio frequency pulses to excite the entire NMR spectrum. Applying such a pulse to a set of nuclear spins simultaneously excites all the single-quantum NMR transitions. In terms of the net magnetization vector, this corresponds to tilting the magnetization vector away from its equilibrium position (aligned along the external magnetic field). The out-of-equilibrium magnetization vector then precesses about the external magnetic field vector at the NMR frequency of the spins. This oscillating magnetization vector induces a voltage in a nearby pickup coil, creating an electrical signal oscillating at the NMR frequency.
== Diagnosis == In addition to evaluating the symptoms above, the health care provider may find decreased or no blood pressure in the arm or leg. Tests to determine any underlying cause for thrombosis or embolism and to confirm presence of the obstruction may include:
==== Declined ==== Grant Moody, Bexar County commissioner from the 3rd precinct Kyle Sinclair, former vice chair of the Bexar County Republican Party, candidate for the 28th district in 2024 and nominee for the 20th district in 2022 (ran in the 21st district)
Sources: en.wikipedia.org
=== Diagnostic Nerve Root Block === A highly targeted Diagnostic Nerve Root Block (DNRB) using local anesthetic (eg, 1 cc of 0.25% bupivacaine) can be used as a diagnostic test to determine if a Tarlov cyst is symptomatic.
=== Phase 2 === AGX-201 (histamine dihydrochloride salt) – histamine H1 receptor antagonist and histamine H3 receptor agonist – migraine [7] BHV-2100 – transient receptor potential cation channel subfamily M member 3 (TRPM3) antagonist – migraine [8] Botulinum toxin A longer acting (IPN-10200; mrBoNT) – acetylcholine release inhibitor and neuromuscular blocking agent – migraine [9] CAM-01 (C-AM-01) – undefined mechanism of action – migraine [10] Dihydroergotamine mesilate (DFN-19) – non-selective monoamine receptor modulator and ergoline – migraine [11] Doxepin intranasal (Dolorac) – tricyclic antidepressant (non-selective monoamine reuptake inhibitor and receptor modulator and other actions) – headache [12] Elismetrep (K-304; MT-8554) – transient receptor potential cation channel subfamily M member 8 (TRPM8) antagonist – migraine [13] Erenumab (Aimovig; AMG-334) – monoclonal antibody against calcitonin gene-related peptide receptor (CGRPR) – headache [14] Eslicarbazepine acetate (Aptiom; BIA 2-093; ESL; Exalief; SEP-0002093; SEP-2093; Stedesa; Zebinix) – sodium channel blocker – migraine [15] IONIS-PKKRx (ISIS-546254; ISIS-PKKRx) – antisense oligonucleotide against kallikrein – migraine [16] Ketoprofen topical (ELS-M11; Topofen) – COX inhibitor/NSAID – migraine [17] LAT-8881 (AOD9604; Tyr-hGH171191) – human growth hormone protein fragment and lanthionine synthetase C-like protein (LanCL) ligand – migraine [18] LU-AG09222 (ALD-1910) – monoclonal antibody against pituitary adenylate cyclase-activating polypeptide (PACAP) – migraine [19] LY-3451838 (PACAP-38 antibody) – monoclonal antibody against pituitary adenylate cyclase-activating polypeptide (PACAP) – migraine [20] Lysergic acid diethylamide (LSD; MM-120) – non-selective serotonin receptor agonist and psychedelic hallucinogen – cluster headache [21] MTX-101 – undefined mechanism of action – migraine [22] Pasireotide (Signifor; SOM-230) – somatostatin receptor agonist – cluster headache [23] Prabotulinumtoxin A (ABP-450; DWP-450; Evosyal; Jeuveau; Nabota; Nuceiva) – acetylcholine release inhibitor and neuromuscular blocking agent – migraine [24] Sepranolone (isoallopregnanolone; UC-1010) – GABAA receptor negative allosteric modulator and neurosteroid – menstrual migraine [25] TRV-250 – δ-opioid receptor (DOR) agonist – migraine [26] (R)-Verapamil – calcium channel blocker and other actions – cluster headache [27] Zelminemab (AMG-301) – monoclonal antibody against pituitary adenylate cyclase-activating polypeptide type I receptor (PAC1R) – migraine [28]
A smaller Bektashi tekke, the Dikmen Baba Tekkesi, is in operation in the Turkish-speaking town of Kanatlarci, North Macedonia that also has stronger ties with Turkish Bektashis. In Kosovo, the relatively small Bektashi community has a tekke in the town of Gjakovë and was under the leadership of Baba Mumin Lama until his passing in 2021. This community recognizes the Bektashi leadership of Tirana. In Bulgaria, the türbes of Kıdlemi Baba, Ak Yazılı Baba, Demir Baba, and Otman Baba function as heterodox Islamic pilgrimage sites, and before 1842 were the centers of Bektashi tekkes. Bektashis continue to be active in Turkey and their semi-clandestine organizations can be found in Istanbul, Ankara and İzmir. The community in Turkey was headed by Debebaba Bedri Noyan from 1960 until his death in 1997. There are currently two rival claimants to the Dedebabate in Turkey: Mustafa Eke and Haydar Ercan. A large, functioning Bektashi tekke was established in the United States in 1954 by Baba Rexheb in the Detroit suburb of Taylor, and the tomb (türbe) of Baba Rexheb continues to draw pilgrims of all faiths.
April 10: Primary Education Law mandates a public girls' school in communes with over 500 inhabitants unless exempted by the Departmental Council. Mixed schools under exemption must be led by a male teacher, though a woman oversees girls' needlework. Communes may offer free schools. Fines or imprisonment are imposed for teachers accepting non-assigned students, except in exempted cases. History and geography become mandatory subjects.
In January 2023, Vice President Geraldo Alckmin met with Vice President Frans Timmermans of the EU Commission in Brasília. During his visit to Brazil, Timmermans said that President Lula's efforts to end destruction in the Amazon deserves support and cooperation from the European Union, adding that the EU could donate up to €750,000 to help the Yanomami people facing a humanitarian crisis. In March 2023, the EU's commissioner for competition Margrethe Vestager met with Vice President Alckmin and other Brazilian officials during a meeting in Brasília to unveil the EU-Brazil bilateral Investment Map. In June 2023, Lula met with EU president Ursula von der Leyen to discuss areas such as environment, science and technology and trade, namely the EU-Mercosur trade deal. Lula expressed concerns over a European Union's side letter proposal of sanctioning Mercosur goods in case they fail to meet environmental goals saying that "between partners there should be mutual confidence not mistrust and sanctions" and that the sanctions could hurt genuine Brazilian green efforts. During the meeting the European Union pledged to donate 20 million euros to the Amazon Fund. In July 2023, numerous Latin American, Caribbean and European leaders, including Lula, attended the III EU-CELAC summit in Brussels to discuss topics such as global hunger, inequalities, poverty and climate change. On the sidelines of the summit, Lula made the case for the EU-Mercosur trade deal and expressed concern for protectionist policies in the agreement.
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.