The short version of RP-HPLC fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-03-24. Anything still debated is marked as such rather than presented as settled.
Thymosin alpha-1 is supplied as a lyophilized powder in most research settings. The solid dissolves readily in water and in common aqueous buffers, and it is typically reconstituted shortly before use. Solutions are clear and colourless at ordinary working concentrations. Because the peptide is hygroscopic, weighing and reconstitution are usually performed with minimal exposure to ambient air. Aliquots are prepared to avoid repeated freeze-thaw cycles, and working solutions are kept cold.
Long-term storage is generally at minus twenty degrees Celsius or colder, preferably desiccated and protected from light. Lyophilized material is more stable than reconstituted solution, which degrades faster at room temperature. Stability depends on pH, ionic strength, and the presence of oxidising agents. Published stability data for the peptide are limited, so storage claims in catalogues should be treated as general guidance rather than measured guarantees. Freeze-thaw cycles are kept to a minimum.
Identity and purity are normally confirmed by reversed-phase high-performance liquid chromatography and mass spectrometry. The expected mass for the acetylated 28-residue peptide is close to 3108 daltons, and a mass shift indicates a modification or truncation. Peptide mapping after enzymatic digestion can resolve sequence-level questions. Counter-ion content, water content, and residual solvents are separate quality attributes that a certificate of analysis may or may not report. Aggregation is monitored by size-exclusion chromatography when relevant.
Storage recommendations center on low temperature, dryness, and protection from repeated freezing and thawing. The intact powder is commonly held at 20 degrees below zero Celsius or colder, while a working solution is divided into single-use aliquots to limit freeze-thaw cycles. Buffered saline or phosphate-buffered saline at neutral pH is frequently used as a diluent. Light sensitivity is not well documented, yet amber vials or foil wrapping are common practice for long-term storage of peptide stocks.
Identity and purity are assessed with a small set of standard peptide methods. Reversed-phase high-performance liquid chromatography separates the main peak from truncated or oxidized species, and its area percentage is the usual purity measure. Mass spectrometry confirms the observed molecular mass against the expected value, while amino acid analysis or peptide mapping checks composition and sequence. Specifications for research-grade material are often stated as 95 percent or higher, though the exact limit depends on the supplier and the intended use.
Laboratory supplies of the peptide usually arrive as a lyophilized powder in sealed vials. The powder is hygroscopic, so a vial should be allowed to reach room temperature before it is opened to prevent condensation on the contents. Weighing and transfer are best performed in a low-humidity environment with clean tools. Once dissolved, the solution should be mixed gently rather than vortexed, because foaming and shear can reduce recovery of the peptide.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Lyophilized form |
| Solubility | Soluble in water | Also soluble in aqueous buffers |
| Storage temperature | -20 °C or below | Desiccated, protected from light |
| Typical analytical method | RP-HPLC with mass spectrometry | Purity and identity |
| Common synonyms | Thymalfasin, T alpha 1 | Sequence identical to natural fragment |
The lyophilized peptide is a white to off-white powder that dissolves freely in water and in aqueous buffers near neutral pH. Because the molecule carries a net negative charge under physiological conditions, saline and phosphate solutions are the usual vehicles, while strongly acidic media are avoided. Stock solutions are commonly divided into small aliquots so that repeated freezing and thawing can be limited, since cycling may encourage aggregation. Solubility in organic solvents is poor and those solvents are seldom used as primary diluents.
Recommended storage for the dry powder is a freezer near minus twenty degrees Celsius, kept desiccated and away from light. Once dissolved, the peptide is less stable and is usually held at two to eight degrees Celsius for short intervals or frozen for longer storage. Stability studies focus on the acetylated terminus and the disulfide linkage because those features define the intact molecule. Common degradation routes include cysteine oxidation, deamidation of asparagine or glutamine side chains, and slow formation of higher-molecular-weight species.
Identity and purity are usually checked by reverse-phase high-performance liquid chromatography, which separates the intact chain from truncated products, together with mass spectrometry for confirmation of the expected mass. Peptide mapping after enzymatic digestion and amino acid analysis add sequence-level evidence. Release testing also covers water content, residual solvents, and counter-ions, all of which influence measured mass and stability. Related-peptide limits are commonly expressed as a percentage of total peak area, with individual unspecified impurities held below a lower threshold.
Thymosin alpha 1 is a 28-amino-acid peptide first isolated from thymosin fraction 5, a bovine thymic extract. Its sequence begins with an acetylated serine residue and carries a high proportion of acidic residues, so the molecule has a net negative charge near neutral pH. Despite the shared name, it is unrelated in sequence to the thymosin beta family. Synthetic material prepared by solid-phase peptide synthesis is identical in sequence to the natural peptide.
Several names appear in the literature for this peptide, including thymalfasin and the abbreviation T-alpha-1. Naming conventions differ among research articles, regulatory documents, and supplier catalogs, which complicates literature searches. Both synthetic and recombinant production routes yield a peptide with the same 28-residue sequence as the thymic isolate. Because the thymosin label also covers unrelated peptides, sources should be compared by sequence rather than by name alone.
The peptide occurs naturally in thymic tissue and has been detected in serum and other biological fluids. Reported concentrations are low, and reliable measurement generally requires immunoassay or mass spectrometry with an enrichment step. It is released from a larger precursor, prothymosin alpha, by proteolytic cleavage, although the enzymes involved are not fully characterized. Whether circulating levels reflect thymic output specifically remains an open question.
A number of cancer immunotherapy agents that target the PD-1 receptor have been developed. One such anti-PD-1 antibody drug, nivolumab, (Opdivo - Bristol Myers Squibb), produced complete or partial responses in non-small-cell lung cancer, melanoma, and renal-cell cancer, in a clinical trial with a total of 296 patients. Colon and pancreatic cancer did not have a response. Nivolumab (Opdivo, Bristol-Myers Squibb) was approved in Japan in July 2014 and by the US FDA in December 2014 to treat metastatic melanoma. Pembrolizumab (Keytruda, MK-3475, Merck), which also targets PD-1 receptors, was approved by the FDA in Sept 2014 to treat metastatic melanoma. Pembrolizumab has been made accessible to advanced melanoma patients in the UK via UK Early Access to Medicines Scheme (EAMS) in March 2015. It is being used in clinical trials in the US for lung cancer, lymphoma, and mesothelioma. It has had measured success, with little side effects. It is up to the manufacturer of the drug to submit application to the FDA for approval for use in these diseases. On October 2, 2015, Pembrolizumab was approved by FDA for advanced (metastatic) non-small cell lung cancer (NSCLC) patients whose disease has progressed after other treatments. Toripalimab is a humanized IgG4 monoclonal antibody against PD-1 which was approved in China in 2018 and in the United States in 2023. Drugs in early stage development targeting PD-1 receptors (checkpoint inhibitors) include pidilizumab (CT-011, Cure Tech) and BMS-936559 (Bristol Myers Squibb).
The epidermis, "epi" coming from the Greek language meaning "over" or "upon", is the outermost layer of the skin. It forms the waterproof, protective wrap over the body's surface, which also serves as a barrier to infection and is made up of stratified squamous epithelium with an underlying basal lamina.
In biochemistry, lipogenesis is the conversion of fatty acids and glycerol into fats, or a metabolic process through which acetyl-CoA is converted to triglyceride for storage in fat. Lipogenesis encompasses both fatty acid and triglyceride synthesis, with the latter being the process by which fatty acids are esterified to glycerol before being packaged into very-low-density lipoprotein (VLDL). Fatty acids are produced in the cytoplasm of cells by repeatedly adding two-carbon units to acetyl-CoA. Triacylglycerol synthesis, on the other hand, occurs in the endoplasmic reticulum membrane of cells by bonding three fatty acid molecules to a glycerol molecule. Both processes take place mainly in liver and adipose tissue. Nevertheless, it also occurs to some extent in other tissues such as the gut and kidney. After being packaged into VLDL in the liver, the resulting lipoprotein is then secreted directly into the blood for delivery to peripheral tissues.
1993/3229) Milk Marketing Board Scheme of Reorganisation (Extension of Period for Application) Order 1993 (S.I. 1993/3230) Merchant Shipping (Musters and Training) (Amendment) Regulations 1993 (S.I. 1993/3231) Merchant Shipping (Pilot Ladders and Hoists) (Amendment) Regulations 1993 (S.I. 1993/3232) Dairy Produce Quotas (Amendment) Regulations 1993 (S.I. 1993/3234) Pensions Increase (Approved Schemes) (National Health Service) (Scotland) Amendment Regulations 1993 (S.I. 1993/3235) Council Tax (Transitional Reduction Scheme) (Scotland) (No.2) Regulations 1993 (S.I. 1993/3236) Railways Act 1993 (Commencement No. 1) Order 1993 (S.I. 1993/3237) Road Traffic Act 1991 (Commencement No. 9 and Transitional Provisions) Order 1993 (S.I. 1993/3238) Road Traffic (Special Parking Areas) (London Boroughs of Richmond upon Thames and Southwark) Order 1993 (S.I. 1993/3239) Act of Sederunt (Sheriff Court Summary Application Rules) 1993 (S.I. 1993/3240) Insurance Accounts Directive (Miscellaneous Insurance Undertakings) Regulations 1993 (S.I. 1993/3245) Companies Act 1985 (Insurance Companies Accounts) Regulations 1993 (S.I. 1993/3246) Animals and Animal Products (Import and Export) Regulations 1993 (S.I. 1993/3247) Artificial Breeding of Sheep and Goats Regulations 1993 (S.I. 1993/3248) Importation of Bees (Amendment) Order 1993 (S.I. 1993/3249) Specified Animal Pathogens Order 1993 (S.I. 1993/3250) Parliamentary Pensions (Additional Voluntary Contributions Scheme) Regulations 1993 (S.I. 1993/3252) Parliamentary Pensions (Consolidation and Amendment) Regulations 1993 (S.I.
Sources: en.wikipedia.org
4,114 parish registers dating before 1792, with 81 indexes 47 registers of banns publications 15 registers for Protestant civil records 7,300 civil registers (1792–1859) stored in 1,002 boxes The total losses exceeded eight million documents. The memory of the Parisian population, preserved since the 16th century, was thus almost entirely obliterated—both that of the "people of Paris" and of the greatest moments in French history, including the births, baptisms, marriages, deaths, and burials of eminent figures. Historian Count de Chastellux wrote: "The destruction of the civil registers stored at the Paris archives (Avenue Victoria) and the registry of the Seine Civil Court is not only a profound disruption for families but also infinitely distressing from a historical perspective. It was the most complete collection of its kind in France, dating back to the reign of Francis I. Within more than 150,000 registers lay solutions to countless questions: historians, biographers, genealogists, topographers, and autograph enthusiasts found a rich and precious mine there." In the second edition of Critical Dictionary of Biography and History (1872), archivist Auguste Jal similarly lamented: "The Civil Archives of Paris were annihilated by fire, both at the Palais de Justice and the depot on Avenue Victoria, during those bloody days of furious hatred, criminal enterprises, and wild and savage acts that marked the few days in mid-May 1871.
== Reaction mechanism == The methylglyoxal molecule consists of two carbonyl groups flanked by a hydrogen atom and a methyl group. In the discussion below, these two carbonyl carbons will be denoted as C1 and C2, respectively. In both the hemithioacetal substrate and the (R)-S-lactoylglutathione product, the glutathione moiety is bonded to the C1 carbonyl group. The basic mechanism of glyoxalase I is as follows. The substrate hemithioacetal is formed when a molecule of glutathione — probably in its reactive thiolate form — attacks the C1 carbonyl of methylglyoxal or a related compound, rendering that carbon tetravalent. This reaction occurs spontaneously in the cell, without the involvement of the enzyme. This hemithioacetal is then bound by the enzyme, which shifts a hydrogen from C1 to C2. The C2 carbonyl is reduced to a tetravalent alcohol form by the addition of two protons, whereas the C1 carbonyl is restored by losing a hydrogen while retaining its bond to the glutathione moiety. A computational study, combined with the available experimental data, suggests the following atomic-resolution mechanism for glyoxalase I. In the active site, the catalytic metal adopts an octahedral coordination geometry and, in the absence of substrate, binds two waters, two opposite glutamates, a histidine and one other sidechain, usually another histidine or glutamates. When the substrate enters the active site, the two waters are shed and the two carbonyl oxygens of the substrate are bound directly to the metal ion.
== Caspase-2-PIDDosome == Caspases are a family of cysteine proteases that play key roles in regulating apoptosis and inflammatory responses. These enzymes are divided into two main groups: initiator and executioner caspases, based on their structure and function. Initiator caspases, such as caspase-8 and caspase-9, become activated through the formation of large protein complexes, which promote dimerization and self-cleavage. Once activated, they initiate the activation of effector caspases, like caspase-3 and caspase-7, which then execute the final stages of programmed cell death. Caspase-2 has similar structure to the initiator caspase-9, particularly due to the presence of a caspase activation and recruitment domain (CARD). Its activation mechanism also involves dimerization, followed by autoprocessing, which is essential for its full activation. Similar to caspase-9 and its role within the apoptosome, the multiprotein complex that facilitates caspase-2 activation has been designated as the "PIDDosome" (Caspase-2-PIDDosome). This structure is formed by the C-terminal fragment of PIDD1 (p53-induced death domain protein 1) and RAIDD (receptor-interacting protein-associated ICH-1/CED-3 homolog with a death domain, also known as CRADD) in a 5:5 stoichiometric ratio. Two additional RAIDD molecules are positioned on top of the core complex, completing its assembly. RAIDD functions as a dual adaptor protein, featuring specialized domains that facilitate key interactions.
Sources: en.wikipedia.org
The political situation in Iran was a flashpoint between the major players in 1945–1946, with the Soviet Union sponsoring two breakaway provinces in northern Iran, adjacent to the Azerbaijan Soviet Socialist Republic. Soviet troops were stationed in northwestern Iran as part of the Anglo-Soviet invasion of Iran during the war. They not only refused to withdraw in 1945 but backed revolts that established short-lived, pro-Soviet separatist national states called the Azerbaijan People's Government and the Republic of Kurdistan. The issue was debated at the United Nations, and in 1946 Moscow abandoned its position, and the conflict was permanently resolved peacefully, with a pro-western government resuming control. Iran did not become a major battlefield of the Cold War, but it had its own history of confrontation with Britain and the United States. The long-standing conflict between Arabs and Jews in Mandatory Palestine continued after 1945, with Britain and in an increasingly impossible situation as the mandate holder. The Balfour Declaration of 1917 calling for a homeland for the Jews was supported in 1947 by both the Soviet Union and the United States. Both countries promptly Recognize the independent state of Israel in 1948. The Soviet Union later broke with Israel to support its Arab enemies. The region was more of an independent trouble zone rather than a playing field of the Cold War, and was not a precipitating factor in the Cold War. By 1953, Arab nationalism based in Egypt was a neutralizing force. The Soviet Union leaned increasingly toward Egypt.
=== Anorexia === Interactions between MCH and chemokines/cytokines that lead to an overall decrease in MCH release and neuron excitability has been linked with infection-induced anorexia. Chemokines and cytokines often appear as the result of inflammation or infection, and they can then damage MCH neurons, which can lead to anorexia in an individual.
=== Anaerobic oxidative decarboxylation === One well-studied example is HemN. HemN or anaerobic coproporphyrinogen III oxidase is a radical SAM enzyme that catalyzes the oxidative decarboxylation of coproporphyrinogen III to protoporphyrinogen IX, an intermediate in heme biosynthesis. Evidence support the idea that HemN utilizes two SAM molecules to mediate radical-mediated hydrogen transfer for the sequential decarboxylation of the two propionate groups of coproporphyrinogen III. Hyperthermophilic sulfate-reducing archaen Archaeoglobus fulgidus enables anaerobic oxidation of long chain n-alkanes. PflD is reported to be responsible for the capacity of A. fulgidus to grow on a wide range of unsaturated carbons and fatty acids. A detailed biochemical and mechanistic characterization of PflD is still undergoing but preliminary data suggest PflD may be a radical SAM enzyme.
Sources: en.wikipedia.org
Lyophilized powder is normally kept at minus twenty degrees Celsius or below, in a sealed container, desiccated and away from light. Reconstituted solutions are less stable and are usually refrigerated and used quickly. Repeated temperature cycling should be avoided.
Mass spectrometry gives the molecular mass, which is compared with the calculated value. Reversed-phase liquid chromatography shows purity and the presence of related impurities. Peptide mapping can verify the amino acid sequence when a higher level of detail is needed.
It reports the tests the supplier performed, which may vary between laboratories and lots. Methods and acceptance criteria are not standardised across suppliers. Buyers often request the actual chromatograms and spectra rather than a summary statement.
Aliquots are typically frozen well below zero Celsius and thawed only once, since repeated cycles promote aggregation and loss. Dilution into a neutral buffer limits degradation during short working periods, and prolonged storage at room temperature is avoided.