The short version of deamidation fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2025-11-14 and is reviewed periodically as new material appears.
Thymosin alpha 1 is a synthetic 28-amino-acid peptide first isolated in 1966 from thymosin fraction 5, a bovine thymus extract. Its chain begins with an acetylated serine residue and ends with asparagine. The native peptide carries a molecular mass near 3,108 daltons. Researchers classify it as an immunomodulatory agent rather than a hormone with a single endocrine target. Early work framed it as a thymus-derived factor that supports T-cell maturation. The synthetic form used in research and clinical products matches the natural sequence.
Immune signaling studies link thymosin alpha 1 to Toll-like receptor pathways, particularly TLR2 and TLR9, on dendritic cells and other antigen-presenting cells. Activation of these receptors promotes maturation of T cells and increases natural killer cell activity. The peptide shifts cytokine output toward a T helper 1 profile, raising interferon gamma and interleukin 2 while modulating interleukin 10. Whether these effects translate into clinical benefit for any specific disease remains a subject of debate. Reported outcomes vary across trials and populations.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular mass | ≈3,108 Da | Synthetic 28-residue peptide |
| Amino acid count | 28 | N-terminal serine carries an acetyl group |
| Appearance | White to off-white powder | Lyophilized solid |
| Water solubility | Freely soluble | Dissolves in aqueous buffer |
| Common synonyms | Thymalfasin; Tα1 | Thymalfasin is the international nonproprietary name |
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, which separates the target peptide from truncated or chemically modified byproducts. Mass spectrometry confirms the expected molecular mass and can indicate acetylation state or sequence errors. Amino acid analysis and peptide mapping supply complementary sequence-level information, while endotoxin testing is relevant for preparations intended for cell or animal work. Purity figures reported by suppliers refer to the method used and are not directly comparable across laboratories unless conditions are stated.
Lyophilized material is typically treated as a hygroscopic solid that should be brought to room temperature before the container is opened, which limits condensation on the powder. Reconstitution is commonly done with sterile water or a buffered diluent, and gentle mixing is preferred over vigorous agitation to reduce foaming and surface adsorption. Because peptides can bind to plastic and glass, diluents containing a small amount of carrier protein are sometimes used in laboratory work. Working solutions are generally aliquoted and prepared fresh rather than subjected to repeated freezing and thawing.
Stability depends on temperature, pH, and the number of freeze-thaw events the sample has experienced. Freeze-dried material is commonly held at -20 °C or colder, while reconstituted liquid is kept cold and used within a short window. Extreme pH and prolonged light exposure can promote deamidation, oxidation, or aggregation, particularly at asparagine and methionine positions. Adsorption to container walls can lower the measured concentration of a dilute solution even when the peptide molecules themselves remain intact.
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.
Thymosin alpha-1 is a synthetic 28-amino-acid peptide whose sequence was first identified in extracts of bovine thymus tissue during the 1970s. The chain carries an acetyl group on its N-terminal serine. Its acidic residue content is high, which produces strong water solubility and an isoelectric point well below neutrality. Material supplied for laboratory and clinical use is manufactured by solid-phase peptide synthesis rather than purified from animal tissue. Different salt forms, such as the acetate, alter the counter-ion content without changing the peptide backbone.
Whether the free 28-residue peptide circulates in human tissue remains debated. The best-documented human source is prothymosin alpha, a larger acidic protein that carries the sequence at its N-terminus. Reports of measurable peptide levels in serum and lymphoid tissue exist, yet some of that signal may come from cross-reacting fragments or from the parent protein. Most reviews therefore treat prothymosin alpha as the established human molecule and describe independent circulation of the small peptide as an unresolved question.
Identity and purity are normally assessed by reversed-phase high-performance liquid chromatography, which separates the peptide from related impurities and truncation products. Mass spectrometry confirms molecular mass and detects modifications such as deamidation or oxidation. Amino acid analysis and peptide mapping provide additional sequence-level confirmation. For research material, a certificate of analysis typically reports these results together with water content and counter-ion identity, since the lyophilized powder is often supplied as an acetate or trifluoroacetate salt.
Several factors accelerate degradation: alkaline pH, elevated temperature, exposure to oxidants, and the presence of residual moisture. Deamidation of asparagine residues and oxidation of methionine are the most commonly reported degradation routes. Because the peptide lacks disulfide bonds, it does not undergo the thiol-related aggregation seen in some other biologics, but physical aggregation can still occur at high concentration. Stability data are product-specific, and extrapolating shelf life between formulations is not reliable.
Lyophilized thymosin alpha-1 is generally stored at or below minus twenty degrees Celsius, protected from moisture and light. Short-term handling at ambient temperature is possible for dry powder, but reconstituted solutions degrade faster and are usually kept at two to eight degrees Celsius with a defined expiry of days rather than weeks. Repeated freeze-thaw cycles should be avoided because they promote aggregation and loss of potency. Exact limits depend on the formulation and should follow the supplier's documentation.
Scientists at the company argued for developing a companion diagnostic and limiting testing of the drug only to patients with biomarkers showing they were likely to respond, and received agreement from management. Some people, including shareholders and analysts, criticized this decision as it limited the potential market size for the drug, while others argued it increased the chances of proving the drug would work and would make clinical trials faster. (The trials would need fewer participants because of the likelihood of greater effect size.) Moving quickly and reducing the risk of failure was essential for catching up with Bristol-Myers Squibb, which had an approximate five year lead over Merck. The phase I study started in early 2011, and Eric Rubin, who was running the melanoma trial, argued for and was able to win expansion of the trial until it reached around 1300 people. This was the largest phase I study ever run in oncology, with the participants roughly divided between melanoma and lung cancer. In 2013, Merck quietly applied for and won a breakthrough therapy designation for the drug. This regulatory pathway was new at the time and not well understood. One of its advantages is that the US FDA holds more frequent meetings with drug developers, reducing the risk of developers of making mistakes or misunderstandings arising from the differences between regulators' expectations and what the developers want to do.
The branched-chain fatty acid synthesizing system uses α-keto acids as primers. This system is distinct from the branched-chain fatty acid synthetase that utilizes short-chain acyl-CoA esters as primers. α-Keto acid primers are derived from the transamination and decarboxylation of valine, leucine, and isoleucine to form 2-methylpropanyl-CoA, 3-methylbutyryl-CoA, and 2-methylbutyryl-CoA, respectively. 2-Methylpropanyl-CoA primers derived from valine are elongated to produce even-numbered iso-series fatty acids such as 14-methyl-pentadecanoic (isopalmitic) acid, and 3-methylbutyryl-CoA primers from leucine may be used to form odd-numbered iso-series fatty acids such as 13-methyl-tetradecanoic acid. 2-Methylbutyryl-CoA primers from isoleucine are elongated to form anteiso-series fatty acids containing an odd number of carbon atoms such as 12-Methyl tetradecanoic acid. Decarboxylation of the primer precursors occurs through the branched-chain α-keto acid decarboxylase (BCKA) enzyme. Elongation of the fatty acid follows the same biosynthetic pathway in Escherichia coli used to produce straight-chain fatty acids where malonyl-CoA is used as a chain extender. The major end products are 12–17 carbon branched-chain fatty acids and their composition tends to be uniform and characteristic for many bacterial species. BCKA decarboxylase and relative activities of α-keto acid substrates The BCKA decarboxylase enzyme is composed of two subunits in a tetrameric structure (A2B2) and is essential for the synthesis of branched-chain fatty acids.
{\displaystyle {\ce {AB + C <=> AC + B}};\quad K_{\rm {B,C}}={\frac {{\ce {[AC][B]}}}{{\ce {[AB][C]}}}}={\frac {K_{\rm {AC}}{\ce {[A][B][C]}}}{K_{\rm {AB}}{\ce {[A][B][C]}}}}={\frac {K_{\rm {AC}}}{K_{\rm {AB}}}}}
== Coaching career == Immediately after Hird retired from playing football, there was much speculation as to whether he would be interested in a coaching role at a club in the AFL, but primarily at Essendon. After initially dodging questions about his future, Hird stated in August 2010 that "There's something in me, deep in my heart, that says at some point I want to coach Essendon". These words came as a surprise to many, including former premiership teammate Matthew Lloyd, who said that Hird had "changed his whole persona in regards to how he's answering his questions... Just in regards to saying, 'I'll coach one day. I want to coach Essendon one day'. Even those type of words, I haven't heard before." These comments by Hird, considered to be Essendon's "favourite son", furthered speculation towards the future of then-Essendon coach Matthew Knights. A rumour emerged following these comments suggesting that Hird was part of an unofficial agreement with the Essendon board to replace Matthew Knights for the 2011 AFL Season. However, two days after Hird's initial comments, he announced that he had changed his mind due to the intense division and speculation over Matthew Knights' future following Hird's initial comments. Hird stated that he was ruling himself out of coaching Essendon for at least three years.
Sources: en.wikipedia.org
Thioesters are prominent active esters, as illustrated by the esters of coenzyme A. Terpenes and terpenoids are generated from active esters. Some biosynthetically significant active esters include isopentenyl pyrophosphate, dimethylallyl pyrophosphate, and geranyl pyrophosphate.
=== Special populations === Globally, bromazepam is contraindicated and should be used with caution in women who are pregnant, the elderly, patients with a history of alcohol or other substance abuse disorders and children. In 1987, a team of scientists led by Ochs reported that the elimination half-life, peak serum concentration, and serum free fraction are significantly elevated and the oral clearance and volume of distribution significantly lowered in elderly subjects. The clinical consequence is that the elderly should be treated with lower doses than younger patients. Bromazepam may affect driving and ability to operate machinery. Bromazepam is pregnancy category D, a classification that means that bromazepam has been shown to cause harm to the unborn child. The Hoffman LaRoche product information leaflet warns against breast feeding while taking bromazepam. There has been at least one report of sudden infant death syndrome linked to breast feeding while consuming bromazepam.
as a vasodilator in severe Raynaud's phenomenon or ischemia of a limb; in pulmonary hypertension. in primary pulmonary hypertension (PPH) The production of prostacyclin is inhibited by the action of NSAIDs on cyclooxygenase enzymes COX1 and COX2. These convert arachidonic acid to prostaglandin H2 (PGH2), the immediate precursor of prostacyclin. Since thromboxane (an eicosanoid stimulator of platelet aggregation) is also downstream of COX enzymes, one might think that the effect of NSAIDs would act to balance. However, prostacyclin concentrations recover much faster than thromboxane levels, so aspirin administration initially has little to no effect but eventually prevents platelet aggregation (the effect of prostaglandins predominates as they are regenerated). This is explained by understanding the cells that produce each molecule, TXA2 and PGI2. Since PGI2 is primarily produced in a nucleated endothelial cell, the COX inhibition by NSAID can be overcome with time by increased COX gene activation and subsequent production of more COX enzymes to catalyze the formation of PGI2. In contrast, TXA2 is released primarily by anucleated platelets, which are unable to respond to NSAID COX inhibition with additional transcription of the COX gene because they lack DNA material necessary to perform such a task. This allows NSAIDs to result in PGI2 dominance that promotes circulation and retards thrombosis. In patients with pulmonary hypertension, inhaled epoprostenol reduces pulmonary pressure, and improves right ventricular stroke volume in patients undergoing cardiac surgery.
=== Aerobic regeneration of NAD+ and further catabolism of pyruvate === In aerobic eukaryotes, a complex mechanism has developed to use the oxygen in air as the final electron acceptor, in a process called oxidative phosphorylation. Aerobic prokaryotes, which lack mitochondria, use a variety of simpler mechanisms.
=== Simmering hostilities === Although the Vaal uprising marked the beginning of an open and sustained revolt, it was preceded by an "underground war" or "series of localised confrontations", for example clashes in Pietermaritzburg in 1982; in Durban and Mdantsane in 1983; and in Crossroads, Atteridgeville, Cradock, Tumahole, and the East Rand earlier in 1984. Over the same period, in Soweto and some other areas, there was a demonstrable upswing in a longstanding habit of persecution of black local councillors. The boycott of the 1984 election, held in the last week of August, was accompanied by large-scale protests, resulting in a large number of arrests. Some of the candidates for the Tricameral Parliament were also targeted in petrol bomb attacks.
Sources: en.wikipedia.org
== Structure == The human OGT gene has 1046 amino acid residues, and is a heterotrimer consisting of two 110 kDa subunits and one 78 kDa subunit. The 110 kDa subunit contains 13 tetratricopeptide repeats (TPRs); the 13th repeat is truncated. These subunits are dimerized by TPR repeats 6 and 7. OGT is highly expressed in the pancreas and also expressed in the heart, brain, skeletal muscle, and the placenta. There have been trace amounts found in the lung and the liver. The binding sites have been determined for the 110 kDa subunit. It has 3 binding sites at amino acid residues 849, 852, and 935. The probable active site is at residue 508. The crystal structure of O-GlcNAc transferase has not been well studied, but the structure of a binary complex with UDP and a ternary complex with UDP and a peptide substrate has been researched. The OGT-UDP complex contains three domains in its catalytic region: the amino (N)-terminal domain, the carboxy (C)-terminal domain, and the intervening domain (Int-D). The catalytic region is linked to TPR repeats by a translational helix (H3), which loops from the C-cat domain to the N-cat domain along the upper surface of the catalytic region. The OGT-UDP-peptide complex has a larger space between the TPR domain and the catalytic region than the OGT-UDP complex. The CKII peptide, which contains three serine residues and a threonine residue, binds in this space.
=== WBSSH definition === The White–Bate-Smith–Swain–Haslam (WBSSH) definition characterized structural characteristics common to plant phenolics used in tanning (i.e., the tannins). In terms of properties, the WBSSH describes the polyphenols as follows:
=== 8 June === Russia claimed to have shot down three Ukrainian drones targeting an air base near Mozdok, in the first such attack in North Ossetia-Alania since the war began. One person was killed in a Russian attack in Kherson Oblast. Another was killed in an airstrike in Kharkiv Oblast. The HUR claimed to have damaged two Russian Su-57 fighter jets for the first time using drones during a strike on the Akhtubinsk air base in Astrakhan Oblast. Drones also damaged the Russian tug boat Inzhener Smirnov and the barge Sectsia 179 in Taganrog Bay. A Ukrainian warplane struck a target in Russia using an air delivered weapon for the first time during an attack on a "command node" in Belgorod Oblast. The ISW assessed that Russia had resumed using the Crimean Bridge to transport fuel into Ukraine for the first time since it was suspended in March 2024 due to Ukrainian attacks.
Per CLIA, each specific laboratory system, assay, examination is graded for level of complexity by assigning scores of 1, 2, or 3 for each of the following seven criteria. A score of 1 is the lowest level of complexity, and a score of 3 is the highest. Score 2 is assigned when the characteristics for a particular test are intermediate between the descriptions listed for scores of 1 and 3. Criteria for categorization:
Sources: en.wikipedia.org
It is a chain of 28 amino acids, with an acetyl group attached to the first serine residue. The synthetic version replicates this sequence. Its molecular mass is about 3,108 daltons.
It is usually described as an immunomodulatory peptide rather than a classic hormone. It acts on immune cells through receptor pathways. No single endocrine organ target defines its function.
Several countries, including Italy and China, allow it for specific indications. The FDA has not approved it as a drug in the United States. Availability depends on local regulation.
Reconstituted solutions are typically kept refrigerated at two to eight degrees Celsius when used within a short window, or frozen in aliquots for longer periods. Repeated freeze-thaw cycles are avoided because they can reduce recovery of intact peptide.