脂肪酸侧链 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 2026-08-01. Numbers and descriptions here follow the published literature rather than marketing material.
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。
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。
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.
| 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 GIP receptor is expressed in pancreatic islets, adipose tissue, and the central nervous system, while GLP-1 receptors are found in pancreatic islets, the gastrointestinal tract, and the brain. Activation of both receptors can enhance glucose-dependent insulin secretion and reduce glucagon release. The relative contribution of each receptor to the overall pharmacological effect remains an area of ongoing investigation. Preclinical studies suggest that GIP receptor agonism may modulate appetite and energy balance, but the precise mechanisms in humans are not fully established.
In clinical research, tirzepatide has been studied in randomized controlled trials for glycemic control and body weight reduction. These trials typically measure changes in hemoglobin A1c and body weight over periods of several months. The drug is administered by subcutaneous injection, and its pharmacokinetic profile supports once-weekly dosing. Post-marketing surveillance continues to evaluate long-term outcomes and rare adverse events.
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.
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.
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.
Purified material is typically handled as a lyophilized powder kept at or below minus twenty degrees Celsius, shielded from light and moisture. In that state the solid remains stable for extended periods, although repeated freeze-thaw cycling can encourage aggregation. Once dissolved, aqueous solutions are less durable and are generally held cold and used within a brief window. Buffer composition, pH and ionic strength all influence degradation rates, and mildly acidic to neutral conditions are commonly examined. Actual shelf life depends on formulation, concentration and container, so stability limits are established experimentally rather than assumed.
Verification of research-grade material involves checking purity, sequence and counter-ion content against a certificate of analysis. Reported purity figures usually reflect chromatographic area percentage and do not by themselves establish biological activity. Independent laboratories may repeat mass confirmation and peptide mapping to detect substitutions or truncations. Open questions concern how residual solvents, trace metals and subtle conformational variants affect measured behavior, and how consistently different suppliers define their specifications. Documentation of analytical methods matters as much as the headline purity number when results are compared across studies.
A documentary by Mike "Zappy" Zapolin, in which famous NBA athlete (and former Keeping Up With the Kardashians star) Lamar Odom seeks out ibogaine and other therapies to heal PTSD, anxiety, and addiction. In Waves and War (2024). A Netflix documentary in which Navy SEALS with PTSD seek therapy using ibogaine through a program run by Stanford University.
$46.5 billion to build a wall on the United States–Mexico border; $45 billion over four years in order to add 100,000 new migrant detention beds. This is a 365% increase in Immigration and Customs Enforcement's budget for detentions; $29.9 billion to Immigration and Customs Enforcement for hiring new agents and covering transportation and deportation costs, with the aim of hiring 10,000 new officers; $17.3 billion to support state and local law enforcement with border enforcement; $10 billion to reimburse the Department of Homeland Security for costs related to border security; $7.8 billion for hiring Border Patrol agents and vehicles, with the aim of hiring 3,000 new agents; $6.2 billion for border technology; and $3.3 billion for hiring immigration judges and staff.
For example, more than 25% of results for "Tiananmen" on TikTok were considered pro-China by the researchers, compared to 16% on Instagram and 8% on YouTube. In other cases, however, Instagram and YouTube showed higher rates of pro-China content than TikTok. For example, 50% of searches about "Uyghur" and "Xinjiang" on YouTube were considered positive, compared to less than 25% on TikTok. The researchers said this is because some YouTube accounts are linked to state actors. According to their survey, people who use TikTok more than three hours daily are significantly more positive about China's human rights record compared to those who do not use the app. TikTok pushed back against the NCRI, saying that making "accounts that interact with the app in a prescribed manner" is not the same as the experience of real users and some of the events being compared happened before TikTok existed.
=== Category:EC 1.5 (act on CH-NH group of donors) === Category:EC 1.5.1 (with NAD+ or NADP+ as acceptor) Dihydrofolate reductase EC 1.5.1.3 Methylenetetrahydrofolate reductase EC 1.5.1.20 Category:EC 1.5.3 (with oxygen as acceptor) Sarcosine oxidase EC 1.5.3.1 (R)-6-hydroxynicotine oxidase EC 1.5.3.6 Dihydrobenzophenanthridine oxidase EC 1.5.3.12 Category:EC 1.5.4 (with a disulfide as acceptor) Category:EC 1.5.5 (with a quinone or similar compound as acceptor) Category:EC 1.5.7 (with an iron–sulfur protein as acceptor) Category:EC 1.5.8 (with a flavin as acceptor) Category:EC 1.5.99 (with other acceptors)
==== Context ==== The formation of the third cabinet followed the resignation of Mirtha Vásquez on the eve of 31 January 2022. This occurred the day after the resignation of the Minister of the Interior, who resigned citing a “structural problem of corruption” and the impossibility of creating consensus. This decision triggered a political crisis, with the previously supportive Purple Party demanding the formation of a capable government or else the resignation of President Pedro Castillo. The third vice president of the Congress Patricia Chirinos (AvP) announced the filing of a motion of censure against the president, citing the "evident corruption of his government."
Sources: en.wikipedia.org
Adenosine-to-inosine (A-to-I) modifications contribute to nearly 90% of all editing events in RNA. The deamination of adenosine is catalyzed by the double-stranded RNA-specific adenosine deaminase (ADAR), which typically acts on pre-mRNAs. The deamination of adenosine to inosine disrupts and destabilizes the dsRNA base pairing, therefore rendering that particular dsRNA less able to produce siRNA, which interferes with the RNAi pathway. The wobble base pairing causes deaminated RNA to have a unique but different structure, which may be related to the inhibition of the initiation step of RNA translation. Studies have shown that I-RNA (RNA with many repeats of the I-U base pair) recruits methylases that are involved in the formation of heterochromatin and that this chemical modification heavily interferes with miRNA target sites. There is active research into the importance of A-to-I modifications and their purpose in the novel concept of epitranscriptomics, in which modifications are made to RNA that alter their function. A long established consequence of A-to-I in mRNA is the interpretation of I as a G, therefore leading to functional A-to-G substitution, e.g. in the interpretation of the genetic code by ribosomes. Newer studies, however, have weakened this correlation by showing that inosines can also be decoded by the ribosome (although in a lesser extent) as adenosines or uracils. Furthermore, it was shown that I's lead to the stalling of ribosomes on the I-rich mRNA.
Sean Kinney said about the new album and the fans' mixed reactions about the band moving on after Staley's death: Look, it's a big move to fucking stand up and move on. Some people, the music connected with them so strongly, their opinions, how they feel about it ... It's amazing that they have such a connection but they seem to act like it happened to them. This happened to us and Layne's family, not them. This is actually our lives. If we're okay with it, why can't you be? This happened to us, this didn't happen to you. But this album isn't about that, it's a bigger universal point. We're all going to fucking die, we're all going to lose somebody, and it fucking hurts. How do you move on? This record is us moving on, and hurting. That, to me, is a victory. I already feel like I've won. Sometimes people ask us, 'Wouldn't Layne have been pissed off that we did this?' And I tell them it would have been the opposite: he would have been pissed off that it took us so long to do this. We're not doing this for money; there is no money in the music business anymore. Jerry and I funded the whole album, and we spent lots of our own money, because we believe in this. And one of the reasons I'm doing this is so more light is turned on to something where the light was turned off. And Cantrell added: "We've toured around the world, we've lost some friends, we buried a dear friend, and somebody that you just can't fucking replace, and then we've chosen by circumstance to get together again.
==== 1998–1999 ==== On August 7, 1998, Andrés Pastrana Arango was sworn in as the President of Colombia. A member of the Conservative Party, Pastrana defeated Liberal Party candidate Horacio Serpa in a run-off election marked by high voter turn-out and little political unrest. The new president's program was based on a commitment to bring about a peaceful resolution of Colombia's longstanding civil conflict and to cooperate fully with the United States to combat the trafficking of illegal drugs. In July 1999, Colombian military forces attacked the town of Puerto Lleras where FARC rebels were stationed. Using U.S. supplied aircraft and equipment, and backed with U.S. logistical support, Colombian government forces strafed and bombed the town for over 72 hours. In the attack, three civilians were killed and several others were wounded as the military attacked hospitals, churches, ambulances, and residential areas. FARC rebels were forced to flee the area and many were killed or wounded. The Colombian government claimed that this was a significant victory, while human rights groups claimed this was proof that "anti-narcotics" aid was actually just military aid being used to fight a leftist insurgency.
CASPIR – The CDC and ATSDR Specimen Packaging, Inventory and Repository (CASPIR), was established as a centralized resource to preserve CDC's valuable specimens and to provide ongoing specimen management support for CDC programs. The biorepository holds over 6.5 million samples. CLIAC - Clinical Laboratory Improvement Act Committee
Sources: en.wikipedia.org
=== Non-destructive sampling protocols === Although the ammonium bicarbonate protocol should not be considered a non-destructive method, it was followed by more 'true' non-destructive methods. The first of these was the eraser protocol, first tested on parchment, but later also applied to bone. The eraser protocol is performed by rubbing a PVC eraser on a piece of parchment or bone. The friction generates triboelectric forces, which causes small particles of the sample to cling to the eraser waste. From the eraser waste collagen can then be extracted and analysed. The eraser protocol was found to work relatively well for parchment, but it is less effective on bone. Additionally, it leaves microscopic traces on the bone surface, which appear very similar to use wear traces and could be an issue for use wear analysis. A second non-destructive protocol is the plastic bag protocol, first published in 2019. It is based on the idea that the normal friction between an object and the plastic bags, commonly used for storing archaeological objects, might be sufficient to extract enough material for ZooMS analysis. A third protocol uses the same triboelectric principle. However, instead of using an eraser, this microgrid protocol employs a fine polishing film to remove very small amounts of material from a sample. The last non-destructive protocol that has been published for ZooMS is the membrane box protocol. The membrane box protocol is based on contact electrification, which is the generation of electrostatic forces due to small localised differences in charge between two objects.
=== Special populations === In children and adolescents, fluoxetine is the antidepressant of choice due to tentative evidence favoring efficacy and tolerability. Evidence supporting an increased risk of major fetal malformations resulting from fluoxetine exposure is limited, although the Medicines and Healthcare products Regulatory Agency (MHRA) of the United Kingdom has warned prescribers and patients of the potential for fluoxetine exposure in the first trimester (during organogenesis, formation of the fetal organs) to cause a slight increase in the risk of congenital cardiac malformations in the newborn. Furthermore, an association between fluoxetine use during the first trimester and an increased risk of minor fetal malformations was observed in one study. However, a systematic review and meta-analysis of 21 studies—published in the Journal of Obstetrics and Gynaecology Canada—concluded, "the apparent increased risk of fetal cardiac malformations associated with maternal use of fluoxetine has recently been shown also in depressed women who deferred SSRI therapy in pregnancy, and therefore most probably reflects an ascertainment bias. Overall, women who are treated with fluoxetine during the first trimester of pregnancy do not appear to have an increased risk of major fetal malformations." Per the US Food and Drug Administration (FDA), infants exposed to SSRIs in late pregnancy may have an increased risk for persistent pulmonary hypertension of the newborn.
Provides a $12 billion boost in air traffic control funding; Provides a new $10 billion for NASA. This includes $700 million for a Mars Telecommunications Orbiter (later renamed the Mars Telecommunications Network); $2.6 billion for the Lunar Gateway space station; $4.1 billion for the development of the Space Launch System rockets for the Artemis IV and Artemis V missions; $20 million for the Artemis IV Orion spacecraft; $1.25 billion for International Space Station operations throughout 2030; $325 million for the US Deorbit Vehicle; $1 billion for improvements at five NASA centers ($120 million for Stennis, $250 million for Kennedy, $300 million for Johnson, $100 million for Marshall, and $30 million for Michoud); $85 million to transfer a space vehicle to a field center that is involved in the administration of the Commercial Crew Program (aimed at moving Space Shuttle Discovery to the Johnson Space Center); Halves funding for the Consumer Financial Protection Bureau.
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 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.