This is a working overview of Photo-oxidation, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-05-18. Anything still debated is marked as such rather than presented as settled.
Receptor activation by tirzepatide raises intracellular cyclic AMP through Gs-coupled signalling at both targets. At the GLP-1 receptor the downstream effect includes glucose-dependent insulin release, suppressed glucagon secretion, delayed gastric emptying, and reduced appetite signalling in the hypothalamus. GIP receptor engagement adds insulinotropic activity and appears to influence lipid handling in adipose tissue. Because both receptors are stimulated at the same time, the pharmacological profile differs from that of selective GLP-1 receptor agonists, and the relative contribution of each arm remains an area of active investigation.
Clinical development proceeded through large phase 3 programmes in type 2 diabetes and in obesity or overweight with at least one weight-related comorbidity. Regulatory approvals followed in several jurisdictions for both indications. Weekly subcutaneous dosing reflects an elimination half-life of roughly five days. Open questions include the durability of metabolic effects after treatment stops, long-term cardiovascular and hepatic outcomes beyond completed trials, and whether the dual mechanism confers benefits independent of total receptor occupancy. Published literature continues to expand on these points. Substantial uncertainty remains about interindividual variability in response.
Tirzepatide is a synthetic linear peptide of 39 amino acids that acts as a dual agonist at the glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptors. Its sequence derives from native GIP but incorporates non-natural residues and a C20 fatty diacid moiety linked to a lysine side chain. The lipophilic chain promotes albumin binding, which slows renal clearance and extends circulation time. The unmodified peptide has a molecular formula of C225H348N48O68 and a molecular mass near 4,813 daltons.
在生理层面，GIP 与 GLP-1 均为肠道内分泌细胞分泌的肠促胰素，进食后参与胰岛素分泌调节与胃排空抑制。Tirzepatide 通过同时激活这两条信号通路，使胰岛素分泌的葡萄糖依赖性增强，并延缓冲胃排空、降低食欲信号。与单一 GLP-1 激动相比，双靶点作用在血糖控制和体重变化上的效应幅度更大，但具体贡献比例仍在研究之中。
脂肪酸侧链的存在使该肽与血浆白蛋白结合能力增强，从而延长循环半衰期，支持每周一次给药的用药间隔。白蛋白结合同时改变组织分布特征，减慢肾脏清除速度。该设计思路在多种长效肽类药物中被反复采用，属于既定的药代动力学策略。
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C225H348N48O68 | Unmodified peptide backbone |
| Molecular mass | approx. 4,813 Da | 39-residue linear chain |
| Receptor targets | GIP and GLP-1 | Dual agonist activity |
| Route | Subcutaneous injection | Weekly administration interval |
| Elimination half-life | approx. 5 days | Supports weekly dosing schedule |
Clinical research programs have evaluated tirzepatide in adults with type 2 diabetes and in adults with obesity or excess weight. Trials generally reported reductions in glycated hemoglobin and body weight across treatment periods of several months. Since these studies enrolled defined populations under controlled conditions, the findings describe group averages rather than individual outcomes. Open questions include the durability of effects after treatment stops, variation among subgroups, and the long-term consequences of sustained dual receptor stimulation. Published trial summaries should be consulted for exact measurements rather than secondary accounts.
Tirzepatide is a synthetic peptide built from 39 amino acid residues. Its backbone derives from the native glucose-dependent insulinotropic polypeptide sequence, altered at several positions to resist enzymatic cleavage. A fatty diacid group attached through a linker extends plasma residence time by promoting reversible binding to serum albumin. The molecule carries a net negative charge near physiological pH and has a reported molecular weight close to 4813 daltons. These features separate it from shorter incretin analogs and account for its prolonged dosing interval.
The peptide activates two G protein-coupled receptors, GIPR and GLP-1R. Binding triggers adenylyl cyclase activity and raises intracellular cyclic AMP in pancreatic beta cells, which potentiates insulin release when glucose is elevated. Signaling in the central nervous system is associated with reduced appetite and lower energy intake, while effects on gastric emptying and glucagon secretion are also reported. Because activity at both receptors is retained, the pharmacological profile is often described as incretin-based rather than selective for a single receptor.
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.
Solid tirzepatide is handled as a lyophilised, hygroscopic peptide powder that should be kept desiccated, protected from light, and stored frozen, typically at or below minus twenty degrees Celsius for long-term retention. Material left at ambient temperature for extended periods can take up moisture, which promotes aggregation and deamidation. Commercial liquid presentations are kept refrigerated between two and eight degrees Celsius and are not frozen. Reconstituted laboratory solutions are generally held cold and used within a short window because hydrolysis and oxidation continue slowly in solution.
Identity and purity are usually established with reversed-phase high-performance liquid chromatography for the main peak and with mass spectrometry for the observed molecular mass. Peptide mapping after enzymatic digestion confirms the primary sequence, while amino acid analysis provides a quantitative composition check. Size-exclusion chromatography and ion-exchange chromatography are used to look for aggregates and charge variants. Water content, residual solvents, and counter-ion content are measured separately, since a lyophilised powder is often reported on an as-is basis unless a correction is applied.
Like most synthetic peptides of this size, the material is commonly supplied as a lyophilised powder that appears white to off-white. It dissolves in aqueous buffers and in mixtures of water with a small proportion of organic solvent, though the fatty acid portion reduces solubility in pure water relative to short peptides. Hygroscopic behaviour is reported for many peptide powders, so weighing is usually performed quickly and under controlled humidity. Working solutions are typically prepared fresh and kept cold.
Long-term storage of lyophilised peptide powder is generally at minus twenty degrees Celsius or colder, with desiccant and protection from light. Short-term storage at two to eight degrees Celsius is common during active use. In solution, stability depends strongly on pH, concentration, and the presence of preservatives, and hydrolysis or aggregation can develop over weeks. Published stability data specific to this molecule are limited, so recommended conditions for research material are usually extrapolated from general peptide handling practice rather than from a dedicated study.
Bulk peptide material is normally characterised by reversed-phase high-performance liquid chromatography, which separates the target sequence from truncation products and other closely related impurities. Ultraviolet detection near 214 nanometres is common because the peptide backbone absorbs in that region. Mass spectrometry, usually electrospray ionisation coupled to a mass analyser, is used to confirm the molecular mass. Because the molecule carries a lipophilic side chain, gradient methods often need a relatively high organic modifier fraction to elute it within a practical retention window.
== Prevention == Preventing recurrence of hyperkalemia typically involves reduction of dietary potassium, removal of an offending medication, and/or the addition of a diuretic (such as furosemide or hydrochlorothiazide). Sodium polystyrene sulfonate and sorbitol (combined as Kayexalate) are occasionally used on an ongoing basis to maintain lower serum levels of potassium, though the safety of long-term use of sodium polystyrene sulfonate for this purpose is not well understood. High dietary sources include meat, chicken, seafood, vegetables such as avocados, tomatoes and potatoes, fruits such as bananas, oranges and nuts.
=== Enlargement to Central Europe === Following the Revolutions of 1989, the OECD began assisting countries in Central Europe (especially the Visegrád Group) to prepare market economy reforms. In 1990, the Centre for Co-operation with European Economies in Transition (now succeeded by the Centre for Cooperation with Non-Members) was established, and in 1991, the programme "Partners in Transition" was launched to offer a partnership to Czechoslovakia, Hungary and Poland, including a membership option for these countries. As a result of this, Poland, Hungary, the Czech Republic and Slovakia, as well as South Korea and Mexico, became members of the OECD between 1996 and 2000.
Magnesium has three stable isotopes: 24Mg, 25Mg and 26Mg. All are present in significant amounts in nature (see table of isotopes above). About 79% of Mg is 24Mg. The isotope 28Mg is radioactive and in the 1950s to 1970s was produced by several nuclear power plants for use in scientific experiments. This isotope has a relatively short half-life (21 hours) and its use was limited by shipping times. The nuclide 26Mg has found application in isotopic geology, similar to that of aluminium. 26Mg is a radiogenic daughter product of 26Al, which has a half-life of 717,000 years. Excessive quantities of stable 26Mg have been observed in the Ca-Al-rich inclusions of some carbonaceous chondrite meteorites. This anomalous abundance is attributed to the decay of its parent 26Al in the inclusions, and researchers conclude that such meteorites were formed in the solar nebula before the 26Al had decayed. These are among the oldest objects in the Solar System and contain preserved information about its early history. It is conventional to plot 26Mg/24Mg against an Al/Mg ratio. In an isochron dating plot, the Al/Mg ratio plotted is 27Al/24Mg. The slope of the isochron has no age significance, but indicates the initial 26Al/27Al ratio in the sample at the time when the systems were separated from a common reservoir.
=== Differential diagnosis === The histopathological features associated with coeliac disease can arise from other conditions as well. Differential diagnosis of negative coeliac blood tests and villous atrophy or increased inter-epithelial lymphocytes includes tropical sprue, eosinophilic gastroenteritis, lactose intolerance, lymphoma, Crohn's disease, Helicobacter pylori, drug-induced enteropathy (azathioprine, methotrexate, mycophenolate, olmesartan, colchicinenon, non-steroidal anti-inflammatory drugs, and proton pump inhibitors), Whipple's disease, giardiasis, radiation enteritis, tuberculosis, Zollinger–Ellison syndrome, collagenous sprue, common variable immunodeficiency, autoimmune enteropathy, HIV enteropathy, small intestinal bacterial overgrowth, and gastrinoma with acid hypersecretion. If the histological changes improve with a gluten-free diet despite negative coeliac disease blood tests, a diagnosis of seronegative coeliac disease may be made. Positive blood tests for coeliac disease with a lack of changes in the bowels can be caused by errors in collecting blood for the test, recent infections, congestive heart failure, chronic liver disease, and hypergammaglobulinemia. Potential coeliac disease, formerly known as "latent coeliac disease", is diagnosed when there are positive coeliac blood tests, positive HLA genetic testing, and a lack of villous atrophy. Non-celiac gluten sensitivity (NCGS) is a functional disorder that causes intestinal and extraintestinal symptoms in response to gluten.
Genetic defects in the collagen fibers of the basement membrane, including Alport syndrome and Knobloch syndrome Autoimmune diseases targeting basement membranes. Non-collagenous domain basement membrane collagen type IV is autoantigen (target antigen) of autoantibodies in the autoimmune disease Goodpasture's syndrome. A group of diseases stemming from improper function of the basement membrane zone are united under the name epidermolysis bullosa. In histopathology, thickened basement membranes are found in several inflammatory diseases, such as lichen sclerosus, systemic lupus erythematosus or dermatomyositis in the skin, or collagenous colitis in the colon.
Sources: en.wikipedia.org
==== FDA assessment ==== In April 2019, the FDA issued a statement declaring that kratom was not approved for any medical use, was potentially unsafe in commercial products available in the United States, and remained on an import alert where imported supplies would be confiscated. On April 4, 2018, the FDA issued the first mandatory recall in its history over concerns of salmonella contamination of several kratom-containing products. Samples of the products, manufactured by Triangle Pharmanaturals, and marketed under the brand name 'Raw Form Organics', tested positive for contamination and the manufacturer did not comply with federal requests for voluntary recall. FDA Commissioner Gottlieb stated that the recall was "...based on the imminent health risk posed by the contamination of this product with salmonella" and not related to other regulatory concerns. Consumers were advised to immediately discard any such products to prevent serious health risks. In February 2018, the commissioner of the FDA, Scott Gottlieb, released a statement describing further opioid-like properties of kratom and stating that it should not be used for any medical treatment or recreational use. Also in 2018, the FDA supervised the voluntary destruction of kratom dietary supplements by a nationwide distributor in Missouri, and encouraged all companies involved in kratom commerce to remove their products from the market.
== History == Initially released in 2002, the VADAR web server has gone through a number of revisions and updates (now in version 1.8). The latest version of the VADAR web server supports the submission of either PDB formatted files or PDB accession numbers and generates extensive tables and high quality graphs for quantitatively and qualitatively assessing protein structures determined by X-ray crystallography, NMR spectroscopy, 3D-threading or homology modelling. A separate website supports the analysis of multiple protein chains – as might be generated from a standard NMR structure determination effort.
=== No development reported === ACH-36 – undefined mechanism of action [22] Alprazolam sublingual – GABAA receptor positive allosteric modulator and benzodiazepine [23] Antalarmin (CP-154526) – corticotropin-releasing hormone (CRH) inhibitor [24] Buspirone controlled release (Buspirone ER) – serotonin 5-HT1A receptor partial agonist and other actions [25] BW-723C86 – serotonin 5-HT2B and 5-HT2C receptor agonist [26] Cannabidiol dry powder inhalation (RLS-103) – cannabinoid receptor modulator and other actions [27] Darigabat (CVL-865; PF-06372865; PF-6372865) – GABAA receptor positive allosteric modulator [28] Divaplon (RU-32698) – GABAA receptor positive allosteric modulator and nonbenzodiazepine/imidazolpyrimidine [29] Fananserin (RP-62203) – serotonin 5-HT2A receptor antagonist and dopamine D4 receptor antagonist [30] FR260010 (FR-260010) – serotonin 5-HT2C receptor antagonist [31] [32] GSK-588045 (GSK588045) – serotonin 5-HT1A, 5-HT1B, and 5-HT1D receptor antagonist [33] GSK-1360707 – serotonin–norepinephrine–dopamine reuptake inhibitor (SNDRI) [34] GT-001 – GABAA receptor positive allosteric modulator [35] Guanfacine extended release (Connexyn; Intuniv; Intuniv XR; S-877503; SHP-503; SPD-503) – α2-adrenergic receptor agonist [36] Itriglumide (CR-2945) – cholecystokinin B (CCKB) receptor antagonist [37] Lohocla-201 (Kindolor) – various actions [38] LY-293284 – serotonin 5-HT1A receptor agonist [39] NMRA-511 (BTRX-323511; NMRA-323511) – vasopressin V1A receptor antagonist [40] Paroxetine (Aropax; BRL-29060; Deroxat; Divarius; FG-7051; Frosinor; Motivan; NNC-207051; Paxil; Seroxat; SI-211103; Tagonis) – selective serotonin reuptake inhibitor (SSRI) [41] Psilocybin (MYCO-001; MYCO-003) – non-selective serotonin receptor agonist and psychedelic hallucinogen [42] PT-00114 (PT100114) – corticotropin-releasing hormone (CRH) inhibitor [43] Research programme: allosteric modulators - Addex Therapeutics – various actions [44] Research programme: AMPA receptor agonists - RespireRx (ampakines; CX compounds) – AMPA receptor agonists and brain-derived neurotrophic factor (BDNF) stimulants [45] Research programme: anxiety and neurological disorder therapeutics - AstraZeneca – various actions [46] Research programme: cannabis-based therapeutics - Skye Bioscience – cannabinoid receptor agonists [47] Research programme: neuropeptide S receptor modulators - Pfizer (WYE-198232) – neuropeptide receptor agonists [48] Research programme: oxytocin receptor agonist - Wyeth – oxytocin receptor agonists [49] RGH-618 – metabotropic glutamate mGlu5 receptor negative allosteric modulator [50] Riluzole (PK-26124; Rilutek; RP-54274) – various actions [51] Risperidone (JNJ-410397-AAA; R-64766; R064766; Risperdal; Risperdal Consta; Risperdal Depot) – atypical antipsychotic (non-selective monoamine receptor modulator) [52] Saripidem (SL-850274) – GABAA receptor positive allosteric modulator and nonbenzodiazepine/imidazopyridine [53] SB-242084 (SB242084) – serotonin 5-HT2C receptor antagonist [54] SRX-246 (API-246) – vasopressin V1A receptor antagonist [55] SYT-510 – anandamide reuptake inhibitor [56] Tebideutorexant (JNJ-3215; JNJ-61393215; Orexin-1) – orexin OX1 receptor antagonist [57] WAY-100135 – serotonin 5-HT1A receptor antagonist [58] Ziprasidone (CP-88059-01; CP-88059-1; Geodon; ME-2112; RQ-00000003; Zeldox) – atypical antipsychotic (non-selective monoamine receptor modulator) [59]
Aminoglycoside resistance is generally mediated by a resistance gene that inactivates the antibiotic via chemical modification. A wide range of such aminoglycoside modifying enzymes are known, including nucleotidyltranferases, phosphotransferases, or acetyltransferases: all enzymes that attach extra chemical groups to the molecule. New antibiotics have been developed based on the knowledge of some of these enzymes, incorporating structural changes that prevent specific groups of resistance enzymes from modifying the drug.
==== Mortality ==== The World Health Organization reports that babies who receive no breast milk are almost six times more likely to die by the age of one month than those who are partially or fully breastfed. Access to healthcare is the single critical determinant of survival or death for the infant.
Sources: en.wikipedia.org
In mass spectrometry, matrix-assisted laser desorption/ionization (MALDI) is an ionization technique that uses a laser energy-absorbing matrix to create ions from large molecules with minimal fragmentation. It has been applied to the analysis of biomolecules (biopolymers such as DNA, proteins, peptides and carbohydrates) and various organic molecules (such as polymers, dendrimers and other macromolecules), which tend to be fragile and fragment when ionized by more conventional ionization methods. It is similar in character to electrospray ionization (ESI) in that both techniques are relatively soft (low fragmentation) ways of obtaining ions of large molecules in the gas phase, though MALDI typically produces far fewer multi-charged ions. MALDI methodology is a three-step process. First, the sample is mixed with a suitable matrix material and applied to a metal plate. Second, a pulsed laser irradiates the sample, triggering ablation and desorption of the sample and matrix material. Finally, the analyte molecules are ionized by being protonated or deprotonated in the hot plume of ablated gases, and then they can be accelerated into whichever mass spectrometer is used to analyse them.
In January 2026, the Moore administration reached annual pay agreements with six state employee unions, but failed to reach an agreement with AFSCME Maryland Council 3, the state's largest union of state government workers, by the December 31 deadline. Despite this, a pay increase for AFSCME-represented workers equivalent to agreements reached with several smaller unions that average 2% was included in Moore's fiscal year 2027 budget proposal.
== Composition == OFM comprises more than 24 collagens (most notably types I and III), but also contains many growth factors, polysaccharides and proteoglycans that naturally exist as part of the extracellular matrix and play important roles in wound healing and soft tissue repair. The composition includes more than 150 different proteins, including elastin, fibronectin, glycosaminoglycans, basement membrane components, and various growth factors, such as vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF) and platelet derived growth factor (PDGF). OFM has been shown to recruit mesenchymal stem cells, stimulate cell proliferation, angiogenesis and vascularogenesis, and modulate matrix metalloproteinase and neutrophil elastase. The porous structure of OFM has been characterized by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), atomic force microscopy (AFM), histology, Sirius Red staining, small-angle x-ray scattering (SAXS), and micro computerized topography (MicroCT). OFM has been shown to contain residual vascular channels that facilitate blood vessel formation through angioconduction.
The Nobel Prize in Physiology or Medicine (Swedish: Nobelpriset i fysiologi eller medicin) is awarded annually by the Swedish Karolinska Institute to scientists in the various fields of physiology or medicine. It is one of the five Nobel Prizes established by the 1895 will of Alfred Nobel (who died in 1896), awarded for outstanding contributions in chemistry, physics, literature, peace, and physiology or medicine. As dictated by Nobel's will, the award is administered by the Nobel Foundation and awarded by a committee that consists of five members and an executive secretary elected by the Karolinska Institute. While commonly referred to as the Nobel Prize in Medicine, Nobel specifically stated that the prize be awarded for "physiology or medicine" in his will. Because of this, the prize can be awarded in a broader range of fields. The first Nobel Prize in Physiology or Medicine was awarded in 1901 to Emil Adolf von Behring, of Germany. Each recipient receives a medal, a diploma and a monetary award that has varied throughout the years. In 1901, von Behring received 150,782 SEK, which was equal to 7,731,004 SEK in December 2008. The award is presented in Stockholm at an annual ceremony on 10 December, the anniversary of Nobel's death. Laureates have won the Nobel Prize in a wide range of fields that relate to physiology or medicine.
Sources: en.wikipedia.org
It is a dual GIP and GLP-1 receptor agonist, frequently grouped with incretin-based peptide therapeutics. It is a peptide rather than a small molecule and is given by subcutaneous injection.
Selective agents engage only the GLP-1 receptor, whereas tirzepatide activates GIP and GLP-1 receptors simultaneously. This difference in receptor coverage is the principal pharmacological distinction emphasised in comparative reviews.
Downstream signalling is partly characterised, but the quantitative contribution of GIP versus GLP-1 receptor activation to metabolic outcomes is not settled. Review articles commonly flag this as an unresolved question rather than a settled finding.
它属于合成修饰肽，同时激动 GIP 与 GLP-1 两种肠促胰素受体。这类分子通常被称为双重肠促胰素受体激动剂，与选择性 GLP-1 激动剂在靶点范围上不同。