A practical reference on fatty diacid: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-01-23. Anything still debated is marked as such rather than presented as settled.
当前公开资料把 tirzepatide 归为肠促胰素类受体双重激动剂。它并非激素天然变体，而是经过序列改造的工程化肽。其分子量、等电点与疏水性等基础参数已在药典和化学数据库中收录，可作为分析检测和质量研究的参照。
Tirzepatide 是一种由 39 个氨基酸组成的合成肽，分子结构上以 GIP 序列为骨架并引入脂肪酸侧链修饰，使其能够同时与葡萄糖依赖性促胰岛素多肽（GIP）受体和胰高血糖素样肽-1（GLP-1）受体结合。这种双重激动特性使它在同类肽类药物中区别于选择性 GLP-1 受体激动剂。该分子最早由一家制药公司在 2010 年代报道，随后进入糖尿病与体重管理领域的临床研究。
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.
| Property | Value | Notes |
|---|---|---|
| 分子类型 | 合成修饰肽 | 39 个氨基酸，含脂肪酸侧链 |
| 受体靶点 | GIP 与 GLP-1 受体 | 双重激动剂 |
| 分子量 | 约 4.8 kDa | 以游离肽计 |
| 外观 | 白色至类白色粉末 | 冻干形态常见 |
| 溶解性 | 可溶于水及水性缓冲液 | 溶解后宜低温保存 |
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.
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.
At the receptor level, tirzepatide activates both the glucose-dependent insulinotropic polypeptide receptor and the glucagon-like peptide-1 receptor. Both belong to the class B family of G protein-coupled receptors and signal largely through cyclic AMP accumulation. The compound binds the two receptors with differing affinity, and the pattern of signaling at each site is described in the literature as biased rather than simply proportional to occupancy. Tissues carrying these receptors include pancreatic islets, adipose tissue, the central nervous system, and the gastrointestinal tract. The relative weight of each receptor population in producing metabolic effects continues to be studied.
Published work supports the view that engaging two incretin receptors produces changes in glucose handling and body weight larger than those seen with single-receptor activation. Why that difference arises is not fully settled. Open questions include how much of the observed weight effect depends on central versus peripheral signaling, and whether the two receptors form interacting complexes. Most reported findings come from controlled trials and animal models, and translation between species is imperfect. Further research is expected to refine these points over time.
Tirzepatide is a synthetic peptide built from 39 amino acid residues. Its sequence is related to human glucose-dependent insulinotropic polypeptide, with modifications that include a C-terminal extension and a C20 fatty diacid joined through a linker. Those changes raise the molecule's affinity for serum albumin, which slows renal filtration and lengthens the time it stays in circulation. The free base has an average molecular mass near 4813.5 daltons. The compound is made by solid-phase peptide synthesis followed by chromatographic purification.
As a peptide, tirzepatide is handled as a lyophilised solid in research settings and as a preserved solution in finished products. Aqueous solubility is pH dependent and reaches a minimum near the isoelectric point, which lies close to pH 5.4. Stock solutions are typically prepared in neutral or slightly basic buffer to limit precipitation. The solid is hygroscopic and should be equilibrated to room temperature before opening so that condensation does not form on the powder surface.
Recommended storage for reference material is a freezer at approximately -20 degrees Celsius, protected from light and moisture. Commercial injectable presentations are stored refrigerated between 2 and 8 degrees Celsius and must not be frozen. Product labelling generally permits a limited period at controlled room temperature once dispensed, with the exact window depending on the presentation. Repeated temperature cycling is avoided because it can promote aggregation or deamidation of the peptide chain.
Identity and purity are assessed by reversed-phase high-performance liquid chromatography, with mass confirmation by electrospray ionisation mass spectrometry. Peptide mapping after enzymatic digestion verifies the primary sequence. Size-exclusion chromatography quantifies aggregates, while circular dichroism provides a secondary-structure fingerprint. Bioanalytical quantification in plasma uses immunoassay or LC-MS/MS. Reported purity for research-grade lots is commonly 95 percent or higher, and residual water content is checked by Karl Fischer titration.
Tirzepatide is a synthetic peptide developed as a dual agonist at the glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 receptors. Its structure is built on a GIP-derived backbone with non-natural amino acid substitutions and a fatty diacid side chain that promotes albumin binding and slows clearance. That modification supports once-weekly subcutaneous dosing. Registrational trial programs reported reductions in body weight and glycated hemoglobin alongside the drug's glycemic effects.
Both receptors are class B G protein-coupled receptors that signal largely through Gs-mediated cyclic AMP production. Activation within pancreatic islets increases glucose-dependent insulin secretion and suppresses glucagon release when glucose is elevated. Outside the pancreas, signaling in the central nervous system and gut appears to influence appetite and gastric emptying. The relative contribution of each receptor to observed clinical effects remains under investigation, and the two pathways are not simply additive in practice.
Reported outcomes in large trials include dose-dependent weight reduction and improvements in glycemic markers over periods ranging from several months to more than a year. Whether the compound alters long-term cardiovascular or renal outcomes is being examined in dedicated outcome studies, so those questions remain open. Labeling describes gastrointestinal effects such as nausea and diarrhea, which tend to appear during dose escalation. Discontinuation rates and the durability of effects after treatment stops vary across study populations and are still debated.
Heinz Kähler: Die Augustusstatue von Primaporta. Köln 1959. Erika Simon: Der Augustus von Prima Porta. Bremen, Dorn 1959. (Opus nobile 13) Hans Jucker: Dokumentationen zur Augustusstatue von Primaporta, in: Hefte des Archäologischen Seminars Bern 3 (1977) S. 16–37. Paul Zanker: Augustus und die Macht der Bilder. München, C. H. Beck 1987, ISBN 3-406-32067-8 Kaiser Augustus und die verlorene Republik, Ausstellung Berlin 1988. Mainz, Zabern 1988. S. 386 f. Nr. 215. Erika Simon: Altes und Neues zur Statue des Augustus von Primaporta, in: G. Binder (Hrsg.), Saeculum Augustum, Bd. 3, Darmstadt, WBG 1991, S. 204–233. Dietrich Boschung: Die Bildnisse des Augustus, Gebr. Mann Verlag, Berlin 1993 (Das römische Herrscherbild, Abt. 1, Bd. 2) ISBN 3-7861-1695-4 Thomas Schäfer: Der Augustus von Primaporta im Wechsel der Medien, in: H. J. Wendel u.a. (Hrsg.), Wechsel des Mediums. Zur Interdependenz von Form und Inhalt, Rostock 2001, S. 37–58. Vinzenz Brinkmann und Raimund Wünsche (eds.): Bunte Götter. Die Farbigkeit antiker Skulptur. Eine Ausstellung der Staatlichen Antikensammlungen und Glyptothek München in Zusammenarbeit mit der Ny Carlsberg Glyptotek Kopenhagen und den Vatikanischen Museen, Rom, Staatliche Antikensammlungen und Glyptothek, München 2004 ISBN 3-933200-08-3. In Italian
This neuromuscular blockade permitted complete paralysis of the diaphragm and enabled control of ventilation via positive pressure ventilation. Mechanical ventilation first became common place with the polio epidemics of the 1950s, most notably in Denmark where an outbreak in 1952 lead to the creation of critical care medicine out of anesthesia. At first anesthesiologists hesitated to bring the ventilator into the operating theater unless necessary, but by the 1960s it became standard operating room equipment. Sir Robert Macintosh (1897–1989) achieved significant advances in techniques for tracheal intubation when he introduced his new curved laryngoscope blade in 1943. The Macintosh blade remains to this day the most widely used laryngoscope blade for orotracheal intubation. In 1949, Macintosh published a case report describing the novel use of a gum elastic urinary catheter as an endotracheal tube introducer to facilitate difficult tracheal intubation. Inspired by Macintosh's report, P. Hex Venn (who was at that time the anesthetic advisor to the British firm Eschmann Bros. & Walsh, Ltd.) set about developing an endotracheal tube introducer based on this concept. Venn's design was accepted in March 1973, and what became known as the Eschmann endotracheal tube introducer went into production later that year. The material of Venn's design was different from that of a gum elastic bougie in that it had two layers: a core of tube woven from polyester threads and an outer resin layer. This provided more stiffness but maintained the flexibility and the slippery surface.
The Peptide Transporter Carbon Starvation (CstA) Family (TC# 2.A.114) is a member of the APC superfamily and consists of proteins from bacteria and archaea. These proteins are of various sizes and topologies. For example, CstA of E. coli has 701 aas with 18 putative TMSs. It has a long N-terminal CstA domain and a short C-terminal DUF4161 domain. This protein is encoded by a carbon starvation inducible gene, cstA, that is under cyclic AMP-CRP control. Circumstantial evidence suggested that it may be a peptide transporter. A Campylobacter jejuni homologue has been shown to transport di- and tripeptides (see TC# 2.A.114.1.5). Proteins currently known to belong to the CstA family are listed in the Transporter Classification Database. As of early 2016, there is no crystal structural data available for members of the CstA family on RCSB.
In radiology, various X-ray views use terminology based on where the X-ray beam enters and leaves the body, including the front to back view (anteroposterior), the back to front view (posteroanterior), and the side view (lateral).
Sources: en.wikipedia.org
The dominions and colonies provided 57 contingents, overwhelmingly of volunteer forces as none had a substantial full-time force; those from Canada alone numbered some 7,400 Altogether, Britain and her empire deployed some half a million soldiers. After the South African War, the Conservative government embarked on a series of reorganisations that had a negative impact on all the auxiliary forces. The Militia was heavily understrength and disorganised, whilst the number of recruits for the Volunteers was falling off and it was becoming apparent that many Volunteer Corps were headed towards financial collapse unless some action was taken. The Territorial Force was created by the Secretary of State for War, Richard Burdon Haldane, following the enactment of the Territorial and Reserve Forces Act 1907 which combined and re-organised the old Volunteer Force with the Yeomanry. As part of the same process, the remaining units of militia were converted to the Special Reserve. Most Volunteer infantry units had unique identities, but lost these in the reorganisation, becoming Territorial battalions of Regular Army infantry regiments. Only one infantry unit, the London Regiment, has maintained a separate identity. The TF was formed on 1 April 1908 and contained fourteen infantry divisions, and fourteen mounted yeomanry brigades. It had an overall strength of approximately 269,000. Haldane designed it to provide a much larger second line for the six divisions of the Expeditionary Force which he was establishing as the centerpiece of the Regular Army.
Alcohol dehydrogenase class-3 is an enzyme that in humans is encoded by the ADH5 gene. This gene encodes glutathione-dependent formaldehyde dehydrogenase or the class III alcohol dehydrogenase chi subunit, which is a member of the alcohol dehydrogenase family. Members of this family metabolize a wide variety of substrates, including ethanol, retinol, other aliphatic alcohols, hydroxysteroids, and lipid peroxidation products. Class III alcohol dehydrogenase is a homodimer composed of 2 chi subunits. It has virtually no activity for ethanol oxidation, but exhibits high activity for oxidation of long-chain primary alcohols and for oxidation of S-hydroxymethyl-glutathione, a spontaneous adduct between formaldehyde and glutathione. This enzyme is an important component of cellular metabolism for the elimination of formaldehyde, a potent irritant and sensitizing agent that causes lacrymation, rhinitis, pharyngitis, and contact dermatitis.
== See also == Carboxypeptidase E Carboxypeptidase A Enzyme category EC number 3.4 Thrombin-activatable fibrinolysis inhibitor aka plasma carboxypeptidase B2 Bacterial transpeptidase, an alanine carboxypeptidase Bradykinin is broken down among other enzymes by carboxypeptidase N DD-Ala carboxypeptidase is a penicillin-binding protein Phenylalanine might inhibit carboxypeptidase A Martha L. Ludwig
Sources: en.wikipedia.org
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。
分子上的脂肪酸侧链使其与血浆白蛋白结合增强，显著延长循环半衰期。半衰期延长后，稳定血药浓度可在较长的给药间隔内维持，因此常见用法为每周一次。
同时激活两条肠促胰素通路可能在胰岛素分泌、胃排空和食欲调节上产生叠加效应。与单靶点相比，临床研究中观察到的血糖与体重变化幅度通常更明显，但各通路的具体贡献比例尚无定论。
It separates molecules by hydrophobicity, which is effective for distinguishing an intact peptide from truncated or chemically modified forms. A C18 column with an acidic water-organic mobile phase is a standard configuration.