This is a working overview of deamidation, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-11-27. Anything still debated is marked as such rather than presented as settled.
Structure-activity work shows that fatty acid length, linker chemistry and the position of acylation all influence albumin affinity and receptor potency. Plasma protein binding exceeds 99 percent, which restricts distribution and slows renal clearance. Degradation proceeds largely through general proteolysis and fatty acid oxidation rather than cytochrome P450 metabolism, so exposure to common oxidative drug interactions is limited. Whether these clearance routes vary meaningfully between individuals is not fully established.
The molecule is a synthetic 39-amino-acid peptide whose backbone derives from the sequence of human glucose-dependent insulinotropic polypeptide, with several substitutions that raise metabolic stability and shift receptor preference. A C20 fatty diacid is attached through a short linker to a lysine side chain, a modification that increases binding to serum albumin. The reported monoisotopic mass is approximately 4813 Da. Near neutral pH the peptide carries a net negative charge, and the lipid tail makes the molecule markedly more hydrophobic than the unmodified parent sequence.
Dual agonism at the GIP and GLP-1 receptors underlies the observed pharmacology. Activation of GLP-1 receptors raises glucose-dependent insulin release, lowers glucagon secretion, slows gastric emptying and reduces appetite. GIP receptor activation contributes additional effects on adipose tissue and on energy balance, and the combined action on appetite appears larger than either pathway alone in animal models. Signalling bias and the relative contribution of each receptor arm to weight-related effects remain areas of active investigation.
After subcutaneous injection, absorption is gradual, and peak plasma levels are generally reached within one to three days. Albumin binding extends the apparent half-life to roughly five days, which supports a weekly administration schedule. Metabolism proceeds mainly through proteolytic cleavage of the peptide backbone and beta-oxidation of the fatty acid chain, rather than through cytochrome P450 pathways. Eliminated fragments are largely recycled through general protein turnover, and excretion of intact drug in urine is minimal. These properties distinguish the molecule from short-acting incretin mimetics.
Tirzepatide is a synthetic peptide of 39 amino acids engineered from the native glucose-dependent insulinotropic polypeptide sequence. Its structure incorporates several non-natural residues and a C-terminal segment derived from glucagon-like peptide-1, together with a C20 fatty diacid moiety attached through a linker. The lipophilic side chain promotes binding to serum albumin, which slows renal clearance after administration. The compound is classified as a dual incretin receptor agonist and is supplied as a lyophilized powder for reconstitution or as a preformulated solution, depending on the presentation.
| Property | Value | Notes |
|---|---|---|
| Molar mass | approximately 4813 Da | calculated from the 39-residue sequence |
| Appearance | white to off-white powder | typical of lyophilised peptide material |
| Solubility class | freely soluble in water | measured value depends on salt form and pH |
| Plasma protein binding | >99 percent | linked to the fatty diacid side chain |
| Class | dual GIP and GLP-1 receptor agonist | receptor activity varies with the assay used |
Lyophilized material is generally held at -20 degrees Celsius or lower, desiccated and protected from light, where it remains stable for extended periods. Reconstituted or ready-to-use solution is usually kept at 2 to 8 degrees Celsius with minimal agitation. Repeated freeze-thaw cycles should be avoided because they promote aggregation and reduce the soluble monomer fraction. Shipment of frozen solid commonly uses dry ice, while refrigerated liquid moves with validated cold packs. Stability beyond documented periods is not established.
Characterization of the peptide relies on reversed-phase high-performance liquid chromatography for purity and related-substance profiling, with ultraviolet detection near 214 nanometers. Mass spectrometry confirms molecular mass and reveals modifications such as oxidation or deamidation. Peptide mapping after enzymatic digestion verifies the amino acid sequence, while amino acid analysis supplies compositional data. Circular dichroism and infrared spectroscopy are used to assess secondary structure, particularly the alpha-helical content that influences aggregation behavior in solution.
Common degradation routes include hydrolysis of labile amide bonds, deamidation of asparagine and glutamine residues, oxidation of methionine and tryptophan, and non-covalent aggregation. Aggregates can form during freeze-thaw cycling, at elevated pH, or when peptide concentration is high. Each route produces characteristic chromatographic or mass shifts that are tracked during stability studies. Whether a given minor impurity alters biological activity is often an open question, and specification limits are typically set on identity and purity rather than on functional data for trace species.
The peptide backbone contains 39 amino acids and includes alpha-aminoisobutyric acid residues, which are not among the standard proteinogenic set. A C20 fatty diacid moiety is attached through a linker, allowing the compound to bind serum albumin and extend its circulation time. This albumin binding is the main reason the molecule supports once-weekly administration rather than more frequent dosing. The measured molecular mass is approximately 4,813 daltons, placing it firmly in the peptide rather than small-molecule class.
Tirzepatide is a synthetic peptide that activates both the glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptors. This dual agonist profile distinguishes it from earlier incretin-based compounds that act on a single receptor. The molecule was engineered from the native GIP sequence and carries several non-natural residues that slow enzymatic breakdown. Researchers designed it to combine the insulinotropic effects of GIP signaling with the appetite and gastric-emptying effects associated with GLP-1 activation.
Development of tirzepatide took place under a research program that sought to test whether simultaneous engagement of two incretin receptors would produce greater metabolic effects than single-receptor agonism. Clinical trials were organized into the SURPASS series for type 2 diabetes and the SURMOUNT series for obesity and weight management. Regulatory clearance for type 2 diabetes came in 2022 in the United States, followed by approval for chronic weight management in 2023. The trial programs reported reductions in glycated hemoglobin and body weight relative to comparators, though long-term cardiovascular and durability data continue to accumulate.
== Function == In mice, the agouti gene encodes a paracrine signalling molecule that causes hair follicle melanocytes to synthesize the yellow pigment pheomelanin instead of the black or brown pigment eumelanin. Pleiotropic effects of constitutive expression of the mouse gene include adult-onset obesity, increased tumor susceptibility, and premature infertility. This gene is highly similar to the mouse gene and encodes a secreted protein that may (1) affect the quality of hair pigmentation, (2) act as an inverse agonist of alpha-melanocyte-stimulating hormone, (3) play a role in neuroendocrine aspects of melanocortin action, and (4) have a functional role in regulating lipid metabolism in adipocytes. In mice, the wild type agouti allele (A) presents a grey phenotype, however, many allele variants have been identified through genetic analyses, which result in a wide range of phenotypes distinct from the typical grey coat. The most widely studied allele variants are the lethal yellow mutation (Ay) and the viable yellow mutation (Avy) which are caused by ectopic expression of agouti. These mutations are also associated with yellow obese syndrome which is characterized by early onset obesity, hyperinsulinemia and tumorigenesis. The murine agouti gene locus is found on chromosome 2 and encodes a 131 amino acid protein. This protein signals the distribution of melanin pigments in epithelial melanocytes located at the base of hair follicles with expression being more sensitive on ventral hair than on dorsal hair.
The four substrates of this enzyme are L-lysine, reduced nicotinamide adenine dinucleotide phosphate (NADPH), oxygen, and a proton. Its products are N(6)-hydroxy-L-lysine, oxidised NADP+, and water. The enzyme is a flavin-containing monooxygenase that uses molecular oxygen as oxidant and incorporates one of its atoms into the starting material. The systematic name of this enzyme class is L-lysine,NADPH:oxygen oxidoreductase (6-hydroxylating). It is also called lysine N6-hydroxylase. It participates in siderophore biosynthesis and uses flavin adenine dinucleotide as a cofactor.
== Physiology == Amino acids, e.g. from ingested food, can be oxidized by the body as an alternative source of energy, yielding urea and carbon dioxide. The oxidation pathway starts with the removal of the amino group by a transaminase; the amino group is then fed into the urea cycle. The first step in the conversion of amino acids into metabolic waste in the liver is removal of the alpha-amino nitrogen, which produces ammonia. Because ammonia is toxic, it is excreted immediately by fish, converted into uric acid by birds, and converted into urea by mammals. Ammonia (NH3) is a common byproduct of the metabolism of nitrogenous compounds. Ammonia is smaller, more volatile, and more mobile than urea. If allowed to accumulate, ammonia would raise the pH in cells to toxic levels. Therefore, many organisms convert ammonia to urea, even though this synthesis has a net energy cost. Being practically neutral and highly soluble in water, urea is a safe vehicle for the body to transport and excrete excess nitrogen. Urea is synthesized in the body of many organisms as part of the urea cycle, either from the oxidation of amino acids or from ammonia. In this cycle, amino groups donated by ammonia and L-aspartate are converted to urea, while L-ornithine, citrulline, L-argininosuccinate, and L-arginine act as intermediates. Urea production occurs in the liver and is regulated by N-acetylglutamate. Urea is then dissolved into the blood (in the reference range of 2.5 to 6.7 mmol/L) and further transported and excreted by the kidney as a component of urine.
== Design constraints == The design of a molecular dynamics simulation should account for the available computational power. Simulation size (n = number of particles), timestep, and total time duration must be selected so that the calculation can finish within a reasonable time period. However, the simulations should be long enough to be relevant to the time scales of the natural processes being studied. To make statistically valid conclusions from the simulations, the time span simulated should match the kinetics of the natural process. Otherwise, it is analogous to making conclusions about how a human walks when only looking at less than one footstep. Most scientific publications about the dynamics of proteins and DNA use data from simulations spanning nanoseconds (10−9 s) to microseconds (10−6 s). To obtain these simulations, several CPU-days to CPU-years are needed. Parallel algorithms allow the load to be distributed among CPUs; an example is the spatial or force decomposition algorithm. During a classical MD simulation, the most CPU intensive task is the evaluation of the potential as a function of the particles' internal coordinates. Within that energy evaluation, the most expensive one is the non-bonded or non-covalent part. In big O notation, common molecular dynamics simulations scale by
The collections of the Library of Congress include more than 32 million catalogued books and other print materials in 470 languages; more than 61 million manuscripts; the largest rare book collection in North America, including the rough draft of the Declaration of Independence, a Gutenberg Bible (originating from the Saint Blaise Abbey, Black Forest—one of only three perfect vellum copies known to exist); over 1 million U.S. government publications; 1 million issues of world newspapers spanning the past three centuries; 33,000 bound newspaper volumes; 500,000 microfilm reels; U.S. and foreign comic books—over 12,000 titles in all, totaling more than 140,000 issues; 1.9 million moving images (as of 2020); 5.3 million maps; 6 million works of sheet music; 3 million sound recordings; more than 14.7 million prints and photographic images including fine and popular art pieces and architectural drawings; the Betts Stradivarius; and the Cassavetti Stradivarius. The library developed a system of book classification called Library of Congress Classification (LCC), which is used by most U.S. research and university libraries. The library serves as a legal repository for copyright protection and copyright registration, and as the base for the United States Copyright Office. Regardless of whether they register their copyright, all publishers are required to submit two complete copies of their published works to the library—this requirement is known as mandatory deposit. Nearly 15,000 new items published in the U.S. arrive every business day at the library.
Sources: en.wikipedia.org
In popular health and wellness trends, the term "detoxification" or "detox" is often used in reference to special diets, supplements, or products that claim to remove toxins from the body. However, the body already removes harmful substances naturally. Organs such as the liver, kidneys, gastrointestinal tract, lungs, and skin work together to get rid of chemicals and waste. Scientific reviews have found limited evidence supporting the effectiveness of commercial "detox" diets or cleansing regimens, because the body's systems do this work every day. The diagram shows a simplified version of the physiological process of metabolism and excretion. Xenobiotic exposure can occur in different ways through different routes. Orally ingested compounds first pass through the gastrointestinal tract and gut microbiome where some xenobiotics can be metabolized before entering the bloodstream, while inhaled, intravenous, or dermal exposures enter circulation more directly. In the bloodstream, xenobiotics are transported to the liver, which acts as the primary site of metabolic detoxification. In hepatocytes, compounds undergo enzymatic transformation in two main phases: Phase I reactions (often mediated by cytochrome P450 enzymes) introduce functional groups, and Phase II reactions conjugate these compounds to increase water solubility and facilitate elimination. In Phase III, metabolites are transported and excreted from the body. The kidneys eliminate many substances in urine, while others are secreted into bile and excreted in feces after intestinal processing.
=== Legal status === In September 2023, the Committee for Medicinal Products for Human Use of the European Medicines Agency recommended authorizing lebrikizumab (Ebglyss) for the treatment of atopic dermatitis. Lebrikizumab was authorized for medical use in the European Union in November 2023. In September 2023, the US Food and Drug Administration (FDA) declined to approve lebrikizumab due to certain findings during an inspection of a contract manufacturer, unrelated to the clinical trial data, safety, or label for lebrikizumab. Lebrikizumab was approved by the FDA in September 2024.
=== Degrees === Petechiae – small pinpoint hematomas less than 3 mm in diameter; Purpura (purple) – a bruise about 3–10 mm in diameter, generally round in shape; Ecchymosis – subcutaneous extravasation of blood in a thin layer under the skin, i.e. bruising, over 1 cm in diameter.
It can do this by abstracting a proton with its basic nitrogen to make a positively charged intermediate and then use another molecule, a buffer, to extract the proton from its acidic nitrogen. In carbonic anhydrases, a histidine proton shuttle is utilized to rapidly shuttle protons away from a zinc-bound water molecule to quickly regenerate the active form of the enzyme. In helices E and F of hemoglobin, histidine influences binding of dioxygen as well as carbon monoxide. This interaction enhances the affinity of Fe(II) for O2 but destabilizes the binding of CO, which binds only 200 times stronger in hemoglobin, compared to 20,000 times stronger in free heme. The tautomerism and acid-base properties of the imidazole side chain has been characterized by 15N NMR spectroscopy. The two 15N chemical shifts are similar (about 200 ppm, relative to nitric acid on the sigma scale, on which increased shielding corresponds to increased chemical shift). NMR spectral measurements shows that the chemical shift of N1-H drops slightly, whereas the chemical shift of N3-H drops considerably (about 190 vs. 145 ppm). This change indicates that the N1-H tautomer is preferred, possibly due to hydrogen bonding to the neighboring ammonium. The shielding at N3 is substantially reduced due to the second-order paramagnetic effect, which involves a symmetry-allowed interaction between the nitrogen lone pair and the excited π* states of the aromatic ring. At pH > 9, the chemical shifts of N1 and N3 are approximately 185 and 170 ppm.
=== Chromatography === Alkylamides can be used as chromatographic stationary phases. Those phases have been investigated for the separation of oligonucleotides. Ion-pair reverse-phase high-performance liquid chromatography is used to separate and analyse the oligonucleotides after automated synthesis.
Sources: en.wikipedia.org
=== Hormones === To cause gall formation, the T-DNA encodes genes for the production of auxin or indole-3-acetic acid via the IAM pathway. This biosynthetic pathway is not used in many plants for the production of auxin, so it means the plant has no molecular means of regulating it and auxin will be produced constitutively. Genes for the production of cytokinins are also expressed. This stimulates cell proliferation and gall formation.
{\displaystyle {\boldsymbol {\sigma }}=-p\mathbf {I} +\mu \left(\nabla \mathbf {u} +(\nabla \mathbf {u} )^{\mathsf {T}}\right)+\left(\zeta -{\tfrac {2}{3}}\mu \right)(\nabla \cdot \mathbf {u} )\mathbf {I} .}
The Foreign Ministry also confirmed that no Malaysians in the country were affected by the strikes, stating that the situation is closely monitored and actively obtaining updates to ensure safety of Malaysians. Prime Minister Anwar Ibrahim described the operation on Facebook as "unusual in scope and nature" as well as constitutes a "clear violation of international law and amounts to an unlawful use of force against a sovereign state". Oman: The Ministry of Foreign Affairs stated that it respects state sovereignty and independence and fully supports international law. In order to avoid escalation and bring about reconciliation, it urged all sides to use moderation and promote communication. Pakistan: The Ministry of Foreign Affairs stated that it attaches "great importance" to the wellbeing of the Venezuelan people, and urges the need for restraint and de-escalation in line with the principles of the Charter of the United Nations. It added that it is engaged with the situation on the ground to ensure the safety and security of Pakistanis in Venezuela. Philippines: The Department of Foreign Affairs stated that it is monitoring the situation in Venezuela and urged "concerned parties to resolve disputes through peaceful means, and to exercise restraint to prevent escalation of conflict". It said the Philippine Embassy in Bogotá, the non-resident mission for Venezuela, had "issued a travel and safety advisory to Filipinos in Venezuela" and was prepared to provide assistance.
Fentanyl is a synthetic opioid with a potency 20 to 40 times that of heroin and 100 times that of morphine; its primary legal utilization is in pain management for cancer patients and those recovering from painful surgeries. Illicit use of fentanyl continues to fuel an epidemic of synthetic opioid drug overdose deaths in the US. From 2011 to 2021, synthetic opioid deaths per year increased from 2,600 overdoses to 70,601. Since 2018, fentanyl and its analogues have been responsible for most drug overdose deaths in the US, causing over 71,238 deaths in 2021. Fentanyl is often mixed, cut, or ingested alongside other drugs, including cocaine and heroin, to boost their effects. The fentanyl epidemic has erupted into a highly acrimonious dispute between the US and Mexican governments. While US officials blame the flood of fentanyl crossing the border primarily on Mexican crime groups utilizing Chinese precursors, former Mexican President Andrés Manuel López Obrador insisted that the main source of this synthetic drug was Asia. He argued that the crisis of a lack of family values in the US drives people to use the drug.
=== Synthetic Yeast 2.0 === As part of the Synthetic Yeast 2.0 project, various research groups around the world have participated in a project to synthesise synthetic yeast genomes, and through this process, optimise the genome of the model organism Saccharomyces cerevisiae. The Yeast 2.0 project applied various DNA assembly methods that have been discussed above, and in March 2014, Jef Boeke of the Langone Medical Centre at New York University, revealed that his team had synthesized chromosome III of S. cerevisiae. The procedure involved replacing the genes in the original chromosome with synthetic versions and the finished synthetic chromosome was then integrated into a yeast cell. It required designing and creating 273,871 base pairs of DNA – fewer than the 316,667 pairs in the original chromosome. In March 2017, the synthesis of 6 of the 16 chromosomes had been completed, with synthesis of the others still ongoing.
Sources: en.wikipedia.org
It is a synthetic peptide of 39 amino acids bearing a lipid side chain. Its size and architecture place it outside the small-molecule class, and laboratories generally handle it with the precautions used for biologic-like molecules.
The fatty diacid side chain promotes strong binding to serum albumin, which slows clearance and yields a half-life of roughly five days. That profile supports once-weekly administration in clinical use.
In vitro assays detect activity at both the GIP and GLP-1 receptors, but the activity ratio depends on the assay system and the signalling pathway measured. The relative contribution of each receptor to clinical effects is still being characterised.
It is a synthetic linear peptide that acts as a dual agonist at the GIP and GLP-1 receptors. It combines a modified incretin backbone with a fatty diacid side chain that extends its circulation time. It is not a small-molecule drug and is not orally absorbed in its native form.