The short version of 脂肪酸侧链 fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2025-10-23 and is reviewed periodically as new material appears.
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。
该化合物的名称与结构由国际非专利名称体系统一维持,不同文献中出现的同义写法主要在拼写顺序或盐形式描述上不同。研究者通常通过受体结合实验、细胞内环磷酸腺苷积累测定以及动物模型来确认其双激动活性。相当一部分分子层面的细节——例如两条受体通路之间的信号交叉作用——尚处于开放问题状态。
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。
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.
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.
| 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 |
固体状态的 tirzepatide 通常以冻干粉形式保存,推荐在低温、避光、干燥条件下存放,常见区间为 2 至 8 摄氏度,长期保存可考虑更低温度并避免反复冻融。冻融循环会导致肽链聚集或析出,从而影响后续定量结果。容器密封性与湿度控制同样是稳定性研究中反复强调的因素。
溶解操作一般使用注射用水或适宜的水性缓冲液,必要时加入少量助溶剂以改善溶解速度,但应避免剧烈涡旋振荡,因为剪切力可能促进聚集。配制后的溶液在冷藏条件下的稳定时间通常短于固体形态,具体时限取决于浓度、缓冲体系与容器材质。是否加入防腐成分,则取决于用途是否为多次取样。
Cold-chain handling is standard for formulated product, with dry powder stored frozen and ready-to-use solutions refrigerated. Light exposure is minimized because photodegradation of certain amino acid side chains is possible. Shipping and temperature-excursion studies are used to establish whether short deviations affect quality attributes. Documentation supplied with research material usually includes a certificate of analysis listing purity, identity confirmation, and water or residual solvent content. Users are expected to confirm that material meets the stated specification before use.
Identity and purity of tirzepatide are assessed mainly by reversed-phase high-performance liquid chromatography with ultraviolet detection, often paired with mass spectrometry. Because the molecule carries several modifications, gradient conditions are adjusted to resolve the intact peptide from deamidation and oxidation products. Enzymatic digestion followed by peptide mapping confirms the primary sequence and locates specific modifications. Quantitation in biological matrices typically uses liquid chromatography with tandem mass spectrometry after solid-phase extraction. Immunoassays are used less often, since antibody cross-reactivity with closely related peptides can bias results.
The peptide shares degradation routes common to modified peptides: deamidation of asparagine and glutamine residues, oxidation of methionine, and backbone hydrolysis under extreme pH. Lyophilized material is generally more stable than a solution, and residual water content directly affects the rate of hydrolysis. In liquid form, aggregation and visible particles can appear after agitation or repeated freeze-thaw cycles. Stability studies therefore track monomer content, aggregate content, and potency over months under defined temperature and humidity.
The compound first appeared in the scientific literature as an investigational agent for type 2 diabetes. Clinical development proceeded through phase 1, phase 2, and phase 3 programs that measured glycemic control as a primary endpoint while recording body weight as a secondary outcome. Regulatory approval in the United States followed in 2022 for glycemic control, and a separate indication for chronic weight management was added later. Subsequent trials have examined cardiovascular outcomes in adults with elevated cardiovascular risk. Debates continue over how much of the observed effect derives from each receptor arm.
Structural work on the molecule centers on a C20 fatty diacid moiety attached through a linker to the peptide backbone. This side chain promotes reversible binding to serum albumin, which slows renal clearance and supports a prolonged action profile. The peptide backbone incorporates aminoisobutyric acid substitutions that limit recognition by digestive enzymes. Together these modifications produce a molecule that is stable enough for subcutaneous delivery but still dependent on careful manufacturing control. Analytical characterization of the active pharmaceutical ingredient typically follows the conventions used for other synthetic peptides.
Tirzepatide is a synthetic peptide composed of 39 amino acids. It acts as a dual agonist at two incretin receptors, the glucose-dependent insulinotropic polypeptide receptor and the glucagon-like peptide-1 receptor. The molecule was designed by modifying the native sequence of glucose-dependent insulinotropic polypeptide to improve metabolic stability and extend its circulation time. Its structure includes several non-natural amino acid residues and a fatty acid side chain. These features distinguish it from earlier single-receptor incretin analogs studied in the same period.
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.
== Thiol specificity == GPx-3 has a wide thiol specificity. The sources of reducing power for GPx-3 in vitro include GSH, cysteine, mercaptoethanol, and dithiothreitol. There is an evidence of effectiveness of homocysteine in reduction of GPx-3: GSH can be completely replaced by reduced homocysteine in vitro.
Before the second half of the nineteenth century, the remarkable potency and specificity of the actions of drugs such as morphine, quinine, and digitalis were explained vaguely and with reference to extraordinary chemical powers and affinities to certain organs or tissues. The first pharmacology department was set up by Rudolf Buchheim in 1847, at the University of Tartu, in recognition of the need to understand how therapeutic drugs and poisons produced their effects. Subsequently, the first pharmacology department in England was set up in 1905 at University College London. Pharmacology developed in the 19th century as a biomedical science that applied the principles of scientific experimentation to therapeutic contexts. The advancement of research techniques propelled pharmacological research and understanding. The development of the organ bath preparation, where tissue samples are connected to recording devices, such as a myograph, and physiological responses are recorded after drug application, allowed analysis of drugs' effects on tissues. The development of the ligand binding assay in 1945 allowed quantification of the binding affinity of drugs at chemical targets. Modern pharmacologists use techniques from genetics, molecular biology, biochemistry, and other advanced tools to transform information about molecular mechanisms and targets into therapies directed against disease, defects or pathogens, and create methods for preventive care, diagnostics, and ultimately personalized medicine.
Jay Johnson, previously head coach of the University of Nevada baseball program, succeeded Andy Lopez who retired after the 2015 season. In his first season as head coach, Johnson guided his team to the programs 17th College World Series appearance and 8th championship series appearance. Johnson resigned from the Wildcat program in June 2021 to accept the head coaching job at LSU. This was after leading the Wildcats to a Pac-12 conference championship and the 18th College World Series appearance in program history; they were eliminated in Omaha by Stanford. In July 2021, Chip Hale was named the new head coach of Arizona baseball. Hale played for the Wildcats under Jerry Kindall and was on the 1986 College World Series championship team; he went on to play, coach and manage in the major leagues for several years, serving as manager of the Arizona Diamondbacks in 2015 and 2016, and most recently serving as the third base coach of the Detroit Tigers. Arizona baseball also has a student section named The Hot Corner. Seventy-five former Arizona baseball players have played in the Major Leagues. Famous alums include Terry Francona, Kenny Lofton, Shelley Duncan, Trevor Hoffman, Mark Melancon, Chip Hale, Craig Lefferts, J. T. Snow, Don Lee, Carl Thomas, Jack Howell, Mike Paul, Dan Schneider, Rich Hinton, Ed Vosberg, Hank Leiber, Ron Hassey, Brad Mills, Joe Magrane, Alex Mejia, Dave Baldwin, Brian Anderson, Jack Daugherty, Scott Erickson, Gil Heredia, Casey Candaele, George Arias, and Scott Kingery.
The cost of data loggers has been declining over the years as technology improves and costs are reduced. Simple single-channel data loggers can cost as little as $25, while more complicated loggers may cost hundreds or thousands of dollars.
Agricultural technology – or AgTech, it is the use of technology in agriculture, horticulture, and aquaculture with the aim of improving yield, efficiency, and profitability. Agricultural technology can be products, services or applications derived from agriculture that improve various input/output processes. Food science – technology in this sector focuses on the development of new functional ingredients and alternative Proteins. Foodservice – technology innovated the way establishments prepare, supply, and serve food outside the home. There's a tendency to create the conditions for the restaurant of the future with robotics and CloudKitchens. Consumer technology – technology allows what we call consumer electronics, which is the equipment of consumers with devices that facilitates the cooking process. Food delivery – as the food delivery market is growing, companies and startups are rapidly revolutionizing the communication process between consumers and food establishments, with platform-to-consumer delivery as the global lead. Supply chain – supply chain activities are considerably moving from digitization to automation.
Sources: en.wikipedia.org
Canadian National Capital Commission: The Gift of Tulips Archived 14 May 2012 at the Wayback Machine Bulb flower production » Tulip, International Flower Bulb Centre Tulip Picture Book, International Flower Bulb Centre
==== Fear and anxiety ==== Oxytocin is typically remembered for its effects on prosocial behaviors, such as its role in facilitating trust and attachment between individuals. However, oxytocin has a more complex role than solely enhancing prosocial behaviors. There is consensus that oxytocin modulates fear and anxiety; that is, it does not directly elicit fear or anxiety. Two dominant theories explain the role of oxytocin in fear and anxiety. One theory states that oxytocin increases approach/avoidance to certain social stimuli, and the second theory states that oxytocin increases the salience of certain social stimuli, causing animals (including humans) to pay closer attention to socially relevant stimuli. Nasally administered oxytocin has been reported to reduce fear, possibly by inhibiting the amygdala (which is thought to be responsible for fear responses). Indeed, studies in rodents have shown oxytocin can efficiently inhibit fear responses by activating an inhibitory circuit within the amygdala. Some researchers have argued oxytocin has a general enhancing effect on all social emotions, since intranasal administration of oxytocin also increases envy and Schadenfreude. Individuals who receive an intranasal dose of oxytocin identify facial expressions of disgust more quickly than individuals who do not receive oxytocin. Facial expressions of disgust are evolutionarily linked to the idea of contagion. Thus, oxytocin increases the salience of cues that imply contamination, which leads to a faster response because these cues are especially relevant for survival.
Bantu tribes were observed to be upholding what was described as Jewish law, including circumcision, in the 16th century. Circumcision and elements of Jewish dietary restrictions are still found among Bantu tribes.
Using a light microscope, it is just barely possible to see tiny green granules—which were named grana. With electron microscopy, it became possible to see the thylakoid system in more detail, revealing it to consist of stacks of flat thylakoids which made up the grana, and long interconnecting stromal thylakoids which linked different grana. In the transmission electron microscope, thylakoid membranes appear as alternating light-and-dark bands, 8.5 nanometers thick. The three-dimensional structure of the thylakoid membrane system has been disputed. Many models have been proposed, the most prevalent being the helical model, in which granum stacks of thylakoids are wrapped by helical stromal thylakoids. Another model known as the 'bifurcation model', which was based on the first electron tomography study of plant thylakoid membranes, depicts the stromal membranes as wide lamellar sheets perpendicular to the grana columns which bifurcates into multiple parallel discs forming the granum-stroma assembly. The helical model was supported by several additional works, but ultimately it was determined in 2019 that features from both the helical and bifurcation models are consolidated by newly discovered left-handed helical membrane junctions. Likely for ease, the thylakoid system is still commonly depicted by older "hub and spoke" models where the grana are connected to each other by tubes of stromal thylakoids. Grana consist of stacks of flattened circular granal thylakoids that resemble pancakes.
Some of the protesters attempted to burn down the building that housed the district committee of the PCR. The Securitate responded with tear gas and water cannons, while police beat up rioters and arrested many of them. Around 21:00 the rioters withdrew. They regrouped eventually around the Timișoara Orthodox Cathedral and started a protest march around the city, but again they were confronted by the security forces.
Sources: en.wikipedia.org
Therefore, the open-chain isomer D-glucose gives rise to four distinct cyclic isomers: α-D-glucopyranose, β-D-glucopyranose, α-D-glucofuranose, and β-D-glucofuranose. These five structures exist in equilibrium and interconvert, and the interconversion is much more rapid with acid catalysis.
=== ΠG === Blood plasma has a good many proteins in it and they exert an inward directed force called the osmotic pressure on the water in hypotonic solutions across a membrane, i.e., in the Bowman's capsule. Because plasma proteins are virtually incapable of escaping the glomerular capillaries, this oncotic pressure is defined, simply, by the ideal gas law:
== Military detention == Annually, the Israeli military arrests approximately 500 to 700 Palestinian children, all under the age of 18. As reported by Addameer, a Palestinian NGO, about 200 of these children remain incarcerated in Israeli prisons. Following the commencement of Israel's aggressive actions in Gaza on 7 October, there has been a noticeable surge in detentions - with over 450 children being taken into custody at various points, as stated by the Palestinian Commission for Detainees and Ex-Detainees Affairs. Since the year 2000, an estimated 13,000 children have been subject to arbitrary detention, interrogation, trial in military courts, and imprisonment. Many Palestinian children are detained in nighttime operations, with some being placed in administrative detention without a fair trial or formal charges. According to Lawyers for Palestinian Human Rights, there are numerous significant human rights issues associated with these procedures. In May 2024, the Israeli military publicly identified several Palestinian children, alleging that they had been acting as Hamas informants, leading the United Nations Special Rapporteur on the occupied Palestinian territories to state the Israeli army often forces detained Palestinian children to become informants. In April 2025, it was reported that Walid Ahmad was the first Palestinian child to die in Israeli prisons. Ahmad was arrested six months prior to his death and kept at the Megiddo Prison after being accused of throwing stones at soldiers in the occupied West Bank.
Supply of oxygen to tissues (bound to hemoglobin, which is carried in red cells) Supply of nutrients such as glucose, amino acids, and fatty acids (dissolved in the blood or bound to plasma proteins (e.g., blood lipids)) Removal of waste such as carbon dioxide, urea, and lactic acid Immunological functions, including circulation of white blood cells, and detection of foreign material by antibodies Coagulation, the response to a broken blood vessel, the conversion of blood from a liquid to a semisolid gel to stop bleeding Messenger functions, including the transport of hormones and the signaling of tissue damage Regulation of core body temperature Hydraulic functions
where the ion AB+ collides with the neutral species M and subsequently breaks apart. The details of this process are described by collision theory. Due to different instrumental configuration, two main different types of CID are possible: (i) beam-type (in which precursor ions are fragmented on-the-flight) and (ii) ion trap-type (in which precursor ions are first trapped, and then fragmented). A third and more recent type of CID fragmentation is higher-energy collisional dissociation (HCD). HCD is a CID technique specific to orbitrap mass spectrometers in which fragmentation takes place external to the ion trap, it happens in the HCD cell (in some instruments named "ion routing multipole"). HCD is a trap-type fragmentation that has been shown to have beam-type characteristics. Freely available large scale high resolution tandem mass spectrometry databases exist (e.g. METLIN with 960,000 molecular standards each with experimental CID MS/MS data), and are typically used to facilitate small molecule identification.
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 acts as an agonist at both the GIP and GLP-1 receptors, two related class B G protein-coupled receptors. This dual activity distinguishes it from single-receptor GLP-1 agonists. The clinical consequences of engaging both receptors are still being characterized.