长效肽设计 raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-04-03. Anything still debated is marked as such rather than presented as settled.
序列层面的改动同时解决了两个问题，即酶解稳定性与肾脏清除速度。天然 GLP-1 在循环中的半衰期仅约两分钟，主要被二肽基肽酶-4 迅速灭活。酰化侧链与白蛋白的可逆结合形成循环储库，使分子缓慢释放并持续激活受体。这种设计思路后来被广泛用于同类长效肽的开发，属于该类药物化学改造的典型范式。
Semaglutide 是一种经结构修饰的胰高血糖素样肽-1 类似物，其主链与内源性 GLP-1(7-36) 约有百分之九十四的序列一致性。第 8 位丙氨酸被 α-氨基异丁酸取代，使二肽基肽酶-4 无法识别原有切割位点。第 34 位赖氨酸换为精氨酸，进一步降低酶解速率。第 26 位赖氨酸经间隔基连接一条含十八个碳的二酸脂肪链，该侧链赋予分子与血浆白蛋白结合的能力。
Clinical development of this compound followed earlier short-acting GLP-1 analogues that required frequent injection. Once-weekly subcutaneous formulations entered use after 2017, and an oral formulation using a permeation enhancer later became available. The oral version pairs the peptide with sodium N-(8-[2-hydroxybenzoyl] amino) caprylate, a carrier that improves uptake across the gastric epithelium. Interest has expanded from glycaemic control into weight management and metabolic liver disease. Regulatory status and approved indications differ between countries, and the product remains subject to ongoing safety monitoring.
Semaglutide is a synthetic peptide that acts as an agonist at the glucagon-like peptide-1 receptor. It is a structural analogue of human GLP-1(7-37), modified to resist enzymatic degradation by dipeptidyl peptidase-4. The peptide backbone contains alpha-aminoisobutyric acid at position 8, a substitution that stabilises the helix and slows cleavage. A fatty diacid side chain attached through a linker at lysine 34 promotes binding to serum albumin, which extends the circulating half-life. These two modifications together allow less frequent administration than native GLP-1 requires.
| Property | Value | Notes |
|---|---|---|
| 分子式 | C187H291N45O59 | 按主链与 C18 二酸侧链计算 |
| 分子量 | 约 4113.6 道尔顿 | 游离碱形式，随反离子略有差异 |
| 外观 | 白色至类白色冻干粉末 | 具吸湿性，需干燥保存 |
| 溶解性 | 微溶于水，易溶于碱性缓冲液 | 溶解性随 pH 升高而改善 |
| 等电点 | 约 5.4 | 影响缓冲液选择与聚集倾向 |
Receptor activation raises intracellular cyclic AMP through Gs coupling, which promotes glucose-dependent insulin release and suppresses glucagon secretion when blood glucose is elevated. Effects outside the pancreas include slower gastric emptying and altered appetite signalling in the hypothalamus and hindbrain. The relative contribution of each tissue to overall metabolic outcomes remains an area of active investigation. Central mechanisms in particular are inferred mainly from animal models and indirect human measures rather than direct observation.
Serum protein binding dominates the pharmacokinetic profile. The attached chain associates strongly with albumin, shielding the peptide from enzymatic attack and slowing filtration by the kidney. This interaction extends the circulation half-life to roughly one week in humans, which supports weekly administration intervals. An oral version pairs the peptide with an absorption enhancer that transiently alters gastric epithelium, permitting limited uptake; bioavailability by that route is substantially lower than by injection.
Semaglutide belongs to the glucagon-like peptide-1 receptor agonist class, a group of synthetic peptides that imitate an incretin hormone released by intestinal L cells after food intake. Native GLP-1 circulates for only a few minutes because dipeptidyl peptidase-4 cleaves it rapidly. The hormone acts on pancreatic islets, the gastrointestinal tract, and several brain regions. Because the natural peptide is short-lived, development work concentrated on analogues that keep receptor activity while resisting enzymatic breakdown and renal clearance.
Receptor binding triggers G protein signaling that raises intracellular cyclic AMP in pancreatic beta cells. Insulin release follows in a glucose-dependent manner, so secretion increases when blood glucose is elevated and diminishes when it is not. The same signaling suppresses glucagon release from alpha cells and slows gastric emptying, which blunts the post-meal glucose rise. In the brain, receptor activation in regions such as the arcuate nucleus is associated with reduced appetite and lower energy intake. How much each of these effects contributes to overall weight change is not fully settled.
Two structural features account for the prolonged half-life of semaglutide. A modified amino acid at position 8 resists cleavage by dipeptidyl peptidase-4, the enzyme that rapidly degrades native GLP-1. A fatty diacid side chain binds serum albumin, which limits renal clearance and protects the peptide from enzymatic breakdown. These modifications yield a plasma half-life of approximately one week in humans, allowing once-weekly administration. The relationship between plasma concentration and clinical effect varies between individuals, and sources of that variability are still being characterized.
Semaglutide is a synthetic peptide analog of glucagon-like peptide-1 (GLP-1), a hormone released from intestinal L-cells after food intake. The compound belongs to the incretin mimetic class and acts at GLP-1 receptors distributed across pancreatic, gastrointestinal, cardiovascular, and central nervous system tissues. Compared with native GLP-1, the molecule carries structural changes that extend its activity from minutes to roughly one week. It is studied for glycemic control in type 2 diabetes and for weight management, and its effects on cardiovascular and other outcomes remain active research areas.
Semaglutide is a synthetic peptide analogue of glucagon-like peptide-1, a gut hormone released by intestinal L cells after food intake. The natural hormone acts on pancreatic and central receptors but is degraded within minutes by dipeptidyl peptidase-4 and other peptidases. Semaglutide belongs to the class of long-acting GLP-1 receptor agonists, a group distinguished by structural changes that slow breakdown and extend circulation time. Its development followed earlier short-acting analogues and reflects a general strategy in peptide drug design: preserve receptor activity while blocking proteolytic clearance.
Three structural changes define the molecule. At position 8 an alpha-aminoisobutyric acid residue replaces alanine, which blocks dipeptidyl peptidase-4 cleavage. At position 34 arginine replaces lysine, and at position 26 a lysine carries a C18 fatty diacid attached through a short linker. The fatty chain binds serum albumin, and this albumin association reduces renal filtration and enzymatic attack. The unchanged backbone retains the receptor contacts that produce signalling. The free base has the formula C187H291N45O59 and a molecular weight near 4114 daltons.
Pharmacological activity arises from agonism at the glucagon-like peptide-1 receptor, a G protein-coupled receptor expressed in the pancreas, the gastrointestinal tract, and the brainstem. Receptor activation raises intracellular cyclic adenosine monophosphate and enhances insulin release in a glucose-dependent manner, an effect that diminishes when blood glucose concentration is low. Other effects include slowed gastric emptying and hypothalamic satiety signalling. These pathways are described well. Receptor desensitisation rates across tissues, relative to the endogenous hormone, are still under investigation, and reported findings differ between laboratories.
The company that developed the compound filed it as a long-acting analogue, and it gained first approval in 2017 for type 2 diabetes. Later authorisations from several regulators extended the indication to chronic weight management, and the World Health Organization added the glucagon-like peptide-1 receptor agonist drug class to its model list of essential medicines in 2023. Production uses solid-phase peptide synthesis followed by side-chain conjugation and chromatographic purification. Supply constraints and cost differences across regions are well documented. Literature on long-term outcomes continues to grow, with many trials reporting surrogate endpoints rather than hard clinical endpoints.
Semaglutide is a synthetic peptide of thirty-one amino acids that shares roughly ninety-four percent sequence identity with human glucagon-like peptide-1. Two substitutions resist enzymatic cleavage by dipeptidyl peptidase-4, and a fatty diacid side chain attached through a linker promotes binding to serum albumin. That albumin binding slows renal clearance and extends the circulating half-life from minutes to approximately one week. The structural changes are well established in the published literature. Whether the same modifications affect receptor signalling bias in ways that matter clinically remains an open question.
The Swiss Federal Tribunal (SFT) has decided not to entertain the appeal filed by the players against the CAS award of 11 January 2016, imposing a 2-year ban on each player following an anti-doping rule violation. The SFT determined that since the players did not formally challenge the jurisdiction of CAS during the arbitration procedure and accepted the application of the CAS Rules (including the rule providing for a de novo hearing, i.e. for a procedure allowing the CAS to conduct a full review of the case), they had lost their right to challenge the CAS jurisdiction in appeal. The SFT added that, even if the players had properly challenged the jurisdiction of CAS, CAS jurisdiction in this matter would have been confirmed, and the appeal would have been dismissed. The players did not seek an injunction against their suspensions when appealing with the Federal Supreme Court, meaning that they would have served their 2016 suspensions even if the guilty verdicts had been cleared. This was to eliminate any risk that a new, two-year period of suspension could be ordered to be served in full if the appeal were unsuccessful.
These physical agents are mostly used in surgical settings as well as after surgery treatments. These sponges absorb blood, allow for coagulation to occur faster, and give off chemical responses that decrease the time it takes for the hemostasis pathway to start.
In September 1992, Austin formed a tag team known as the Hollywood Blonds with Brian Pillman, at the behest of lead booker Dusty Rhodes. Austin would later say that he was not excited about being placed into a tag team, as he was earmarked for a run with the WCW United States Heavyweight Championship with Harley Race as his manager. Initially billed under their individual personas, Pillman decided the pair needed their own finishing move, ring gear and team name, with traveling partner Scott Levy proposing the Hollywood Blonds, used in the 1970s by Buddy Roberts and Jerry Brown. At Halloween Havoc in October 1992, Austin (substituting for Terry Gordy) teamed with "Dr. Death" Steve Williams to wrestle Dustin Rhodes and Windham for the unified WCW and NWA World Tag Team Championship, wrestling to a 30-minute time limit draw. On March 27, 1993, the Hollywood Blonds won the unified NWA and WCW World Tag Team Championship by defeating Ricky Steamboat and Shane Douglas, and held the championship for five months. In the main event of Clash of the Champions XXIII in June 1993, the Blondes defended their championship against Ric Flair and Arn Anderson in a two-out-of-three-falls, where despite losing the first two falls, retained the championship as the second fall had been determined by a disqualification caused by Barry Windham. At Clash of the Champions XXIV In August 1993, Austin and Pillman were scheduled to defend their championship against Anderson and Paul Roma but a legitimately injured Pillman was replaced by Steven Regal, with whom Austin lost to Anderson and Roma.
nonideological: i.e., profit driven; hierarchical: few elites and many operatives; limited or exclusive membership: maintain secrecy and loyalty of members; perpetuating itself: Recruitment process and policy; willing to use illegal violence and bribery; specialized division of labor: to achieve organization goal; monopolistic: Market control to maximize profits; and, has explicit rules and regulations: Codes of honor. Definitions need to bring together its legal and social elements. OC has widespread social, political and economic effects. It uses violence and corruption to achieve its ends: "OC when group primarily focused on illegal profits systematically commit crimes that adversely affect society and are capable of successfully shielding their activities, in particular by being willing to use physical violence or eliminate individuals by way of corruption." It is a mistake to use the term "OC" as though it denotes a clear and well-defined phenomenon. The evidence regarding OC "shows a less well-organized, very diversified landscape of organizing criminals…the economic activities of these organizing criminals can be better described from the viewpoint of 'crime enterprises' than from a conceptually unclear frameworks such as 'OC'." Many of the definitions emphasize the 'group nature' of OC, the 'organization' of its members, its use of violence or corruption to achieve its goals and its extra-jurisdictional character...OC may appear in many forms at different times and in different places.
=== Research === Jennette's research encompasses clinical research based on evaluation of data obtained from patient medical records, clinical laboratory data, and pathologic evaluation of kidney biopsy specimens; basic research based on experimental investigations using specimens from patients or animal models of kidney disease; and translational research designed to apply (translate) basic research discoveries into improved diagnosis and treatment of disease in patients. Ronald J. Falk has been a colleague in many of his research works.
Sources: en.wikipedia.org
== History == In the 19th century, the mass-to-charge ratios of some ions were measured by electrochemical methods. The first attempt to measure the mass-to-charge ratio of cathode ray particles, assuming them to be ions, was made in 1884-1890 by German-born British physicist Arthur Schuster. He put an upper limit of 10^10 coul/kg, but even that resulted in much greater value than expected, so little credence was given to his calculations at the time. In 1897, the mass-to-charge ratio of the electron was first measured by J. J. Thomson. By doing this, he showed that the electron was in fact a particle with a mass and a charge, and that its mass-to-charge ratio was much smaller than that of the hydrogen ion H+. In 1898, Wilhelm Wien separated ions (canal rays) according to their mass-to-charge ratio with an ion optical device with superimposed electric and magnetic fields (Wien filter). In 1901 Walter Kaufman measured the increase of electromagnetic mass of fast electrons (Kaufmann–Bucherer–Neumann experiments), or relativistic mass increase in modern terms. In 1913, Thomson measured the mass-to-charge ratio of ions with an instrument he called a parabola spectrograph. Today, an instrument that measures the mass-to-charge ratio of charged particles is called a mass spectrometer.
==== Section E: Air Conditioning, Heat Pumps, and Energy Recovery ==== IIR's Section E coordinates the work of both "Commission E1: Air-Conditioning" and "Commission E2: Heat Pumps and Heat Recovery". The core activities and interests of both Commissions are strongly connected, resulting in tight collaboration and jointly organised conferences. Air-conditioning is a subject that is now more frequently addressed due to both better comfort in an increasing number of countries and the effects of global warming. Now, even countries where demand for air-conditioning during summer months was limited, due to a cooler climate, require the operation of an air-conditioning plant for longer periods. The demand for heating is nevertheless significant, and the most efficient system to provide heating is undoubtedly the heat pump. No other technology can provide net primary energy savings, economic benefits to users and reduced climate impact at the same time. As it is also able to provide a cooling effect, it is theorised that heat pumps are expected to become a more common solution for year-round needs. When combined with heat recovery-capable buildings or industrial plants, it is expected that cooling and heating requirements can be met in an efficient, reliable, cost-effective, and environmentally friendly manner.
==== P ==== Piracuí – known in the Brazilian Amazon region as "farinha de peixe" (fish meal), it is traditionally made from dried salted fish that is crushed or shredded. Prawn cracker – a form of deep fried snack made from Tapioca flour and prawn.
The green fluorescent protein (GFP) is often used in genetics as a marker. Many substances, such as proteins, have significant light absorption bands in the ultraviolet that are of interest in biochemistry and related fields. UV-capable spectrophotometers are common in such laboratories. Ultraviolet traps called bug zappers are used to eliminate various small flying insects. They are attracted to the UV and are killed using an electric shock, or trapped once they come into contact with the device. Different designs of ultraviolet radiation traps are also used by entomologists for collecting nocturnal insects during faunistic survey studies.
During conflict, individuals receiving nasally administered oxytocin demonstrate more frequent defense-motivated responses toward in-group members than out-group members. Further, oxytocin was correlated with participants' desire to protect vulnerable in-group members, despite that individual's attachment to the conflict. Similarly, it has been demonstrated that when oxytocin is administered, individuals alter their subjective preferences to align with in-group ideals over out-group ideals. These studies demonstrate that oxytocin is associated with intergroup dynamics. Further, oxytocin influences the responses of individuals in a particular group to those of another group. The in-group bias is evident in smaller groups; however, it can also extend to groups as large as one's entire country, leading to a strong national zeal. A study done in the Netherlands showed that oxytocin increased the in-group favoritism of their nation while decreasing acceptance of members of other ethnicities and foreigners. People also show more affection for their country's flag while remaining indifferent to other cultural objects when exposed to oxytocin. It has thus been hypothesized that this hormone may be a factor in xenophobic tendencies secondary to this effect. Thus, oxytocin appears to affect individuals at an international level where the in-group becomes a specific "home" country, and the out-group grows to include all other countries.
Sources: en.wikipedia.org
差别集中在三处：第 8 位残基被非天然氨基酸取代，第 34 位换成精氨酸，第 26 位增加一条脂肪酸侧链。前两处改动降低酶解速率，侧链则通过白蛋白结合延长循环时间。综合结果是半衰期从约两分钟延长到约一周。
胰岛素释放需要细胞内环腺苷酸与钙信号升高，同时依赖葡萄糖代谢产生的协同信号。血糖水平较低时协同信号不足，分泌增强有限。这一机制在降糖效果与低血糖风险之间提供了缓冲。
白蛋白结合是主要原因，它减少肾小球滤过并保护分子免受蛋白酶降解。序列修饰带来的酶解抵抗同样不可忽略，二者共同作用。脂肪链的疏水性还会影响组织分布，但其对总半衰期的贡献程度仍在研究之中。
It belongs to the incretin mimetic class and acts as a long-acting glucagon-like peptide-1 receptor agonist. The class includes several peptides with different half-lives and routes of administration.