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 2025-10-12. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Acylated GLP-1 receptor agonist | 31-residue synthetic peptide |
| Molecular formula | C187H291N45O59 | established for the free peptide |
| Appearance | White to off-white powder | as supplied before formulation |
| Solubility | Freely soluble in water | aqueous buffers near neutral pH |
| Typical storage | 2 to 8 degrees Celsius, protected from light | powder and solution forms differ in shelf life |
Identity and purity are usually assessed by reverse-phase high-performance liquid chromatography coupled to mass spectrometry. Retention time and observed mass are compared against a reference standard run under identical conditions. Impurity profiles reveal deamidation products, oxidized methionine variants, and truncated fragments that arise during synthesis or storage. Peptide mapping through enzymatic digestion confirms the primary sequence, while amino acid analysis offers an independent check on overall composition.
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.
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.
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.
Combination of small size, ease of engineering, high affinity and specificity makes Affibody molecules suitable alternative as monoclonal antibodies for both molecular imaging and therapeutical applications, especially for the receptor-overexpressing tumors. These proteins are characterized by a high rate of extravasation and rapid clearance of non-bound tracer from the circulation, as well as other nonspecific compartments, when compared to antibodies and their fragments
=== FY 2019–20 === On June 5, 2019, Pritzker signed a bipartisan $40-billion balanced budget for the 2019–20 fiscal year. The budget included $29 million in additional funding for efforts to encourage participation in the U.S. Census. Public spending increases were paid for by tax increases. A separate bill Pritzker signed imposed sales taxes on online retailers, a tax on insurance companies, and decoupled the Illinois state income tax from a federal tax cut for companies that bring their foreign profits to the U.S. The budget neglected any potential revenue that might be collected from the legalization of recreational marijuana. In addition, people who owed taxes from between June 30, 2011, and July 1, 2018, were able to take advantage of a "tax amnesty" program that allowed them to pay without penalty. The governor's office had expected a $150-million surplus, which it planned to use to pay down the state's $6-billion backlog of unpaid bills.
== Function == Several lines of evidence suggest that PD-1 and its ligands negatively regulate immune responses. PD-1 knockout mice have been shown to develop lupus-like glomerulonephritis and dilated cardiomyopathy on the C57BL/6 and BALB/c backgrounds, respectively. In vitro, treatment of anti-CD3 stimulated T cells with PD-L1-Ig results in reduced T cell proliferation and IFN-γ secretion. IFN-γ is a key pro-inflammatory cytokine that promotes T cell inflammatory activity. Reduced T cell proliferation was also correlated with attenuated IL-2 secretion and together, these data suggest that PD-1 negatively regulates T cell responses. Experiments using PD-L1 transfected DCs and PD-1 expressing transgenic (Tg) CD4+ and CD8+ T cells suggest that CD8+ T cells are more susceptible to inhibition by PD-L1, although this could be dependent on the strength of TCR signaling. Consistent with a role in negatively regulating CD8+ T cell responses, using an LCMV viral vector model of chronic infection, Rafi Ahmed's group showed that the PD-1-PD-L1 interaction inhibits activation, expansion and acquisition of effector functions of virus specific CD8+ T cells, which can be reversed by blocking the PD-1-PD-L1 interaction. Expression of PD-L1 on tumor cells inhibits anti-tumor activity through engagement of PD-1 on effector T cells. Expression of PD-L1 on tumors is correlated with reduced survival in esophageal, pancreatic and other types of cancers, highlighting this pathway as a target for immunotherapy.
Sources: en.wikipedia.org
=== Books === Becker, Katja; Engelen, Eva-Maria; Vec, Miloš (1 January 2003), Ethisierung - Ethikferne: Wie viel Ethik braucht die Wissenschaft? (in German) (1st ed.), Berlin: Walter de Gruyter GmbH & Co.KG, p. 243, ISBN 9783050082219 Becker, Katja; Seltzer, Paul M. (February 2011). Apicomplexan Parasites: Molecular Approaches toward Targeted Drug Development. Drug Discovery in Infectious Diseases. Vol. 2 (1st ed.). Weinheim: Wiley-Blackwell. p. 550. ISBN 978-3-527-32731-7.
On 1 March, the Department of Food and Veterinary of Lithuania announced that horse meat was found in three canned beef brands sold by Latvian company Kuršu Zeme. Canned beef made by the Latvian company was removed from sale in Lithuania. === Wiljo Import en Export B.V. and Vleesgroothandel Willy Selten B.V. === On 10 April 2013, it was reported that two Dutch trading companies, owned by the same person whom food safety officials had previously investigated, may have supplied 50,000 metric tonnes of adulterated beef containing horse meat since January 2011. On 7 February 2013, it was revealed by the Food Standards Agency that the Findus beef lasagne range in the UK, France, Norway, and Sweden, and the shepherd's pie and moussaka ranges in France, contained horse meat without proper declaration or official scrutiny. The contamination may have gone on since summer 2012 according to a leaked document.
=== Physical properties === A lutetium atom has 71 electrons, arranged in the configuration [Xe] 4f145d16s2. Lutetium is generally encountered in the +3 oxidation state, having lost its two outermost 6s and the single 5d-electron. The lutetium atom is the smallest among the lanthanide atoms, due to the lanthanide contraction, and as a result lutetium has the highest density, melting point, and hardness of the lanthanides. As lutetium's 4f orbitals are highly stabilized only the 5d and 6s orbitals are involved in chemical reactions and bonding; thus it is characterized as a d-block rather than an f-block element, and on this basis some consider it not to be a lanthanide at all, but a transition metal like its lighter congeners scandium and yttrium.
γ-Butyrolactone (GBL) or gamma-butyrolactone is an organic compound with the formula O=CO(CH2)3. It is a hygroscopic, colorless, water-miscible liquid with a pleasant odor. It is the simplest 4-carbon lactone. It is mainly used as an intermediate in the production of other chemicals, such as N-methyl-2-pyrrolidone. In humans, GBL acts as a prodrug for gamma-hydroxybutyric acid (GHB) and is often used as a recreational drug. GHB acts as a central nervous system (CNS) depressant with effects similar to those of barbiturates.
Sources: en.wikipedia.org
== Thermodynamics and inorganic chemistry == An alternative quantitative approach to inorganic chemistry focuses on energies of reactions. This approach is highly traditional and empirical, but it is also useful. Broad concepts that are couched in thermodynamic terms include redox potential, acidity, phase changes. A classic concept in inorganic thermodynamics is the Born–Haber cycle, which is used for assessing the energies of elementary processes such as electron affinity, some of which cannot be observed directly.
The Serbsky Center, Moscow Institute of Psychiatry, and Russian Center of Vegetative Pathology are reported to have confirmed the effectiveness of phenylpiracetam describing the following effects: improvement of regional blood flow in ischemic regions of the brain, reduction of depressive and anxiety disorders, increase the resistance of brain tissue to hypoxia and toxic effects, improving concentration and mental activity, a psycho-activating effect, increase in the threshold of pain sensitivity, improvement in the quality of sleep, and an anticonvulsant action, though with the side effect of an anorexic effect in extended use.
The most common form of body modification related to the penis is circumcision: removal of part or all of the foreskin, and sometimes the frenulum. It is most commonly performed as an elective procedure for prophylactic, cultural, or religious reasons. Infant circumcision can employ modern devices such as the Gomco clamp, Plastibell, and Mogen clamp. The ethics of circumcision in children is a source of controversy. Among the world's major medical organizations, there is a consensus that circumcision reduces heterosexual HIV infection rates in high-risk populations during penile-vaginal sex. There are differing perspectives on the prophylactic efficacy and cost effectiveness of circumcision in developed nations. Circumcision plays a significant role in many of the world's cultures. When performed for religious reasons, it is most common among both Jews and Muslims, among whom it is near-universal.
Sources: en.wikipedia.org
Native GLP-1 is degraded within minutes by dipeptidyl peptidase-4 and neutral endopeptidases. Semaglutide carries a non-natural amino acid at position eight that blocks that cleavage, and a fatty diacid side chain that binds albumin. The result is a much longer duration of action than the native hormone.
The fatty diacid chain associates strongly with serum albumin, which keeps the peptide in circulation and shields it from rapid renal clearance. Bound peptide is released gradually, producing a sustained receptor signal. This mechanism also reduces the peak-to-trough variation seen with shorter-acting analogues.
The balance between peripheral receptor activation and signalling in the central nervous system is not fully resolved. The extent to which slowed gastric emptying accounts for reduced energy intake, compared with direct effects on appetite circuits, is debated. Long-term effects on lean mass and on tissues outside the gut and brain are still under study.
It is a synthetic peptide of 31 amino acids, built to resemble the natural incretin hormone GLP-1. Because of its size and composition it is handled analytically like other therapeutic peptides, using chromatographic and mass spectrometric methods rather than the techniques typical of small organic drugs.