If you have been reading about deamidation and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2025-11-03. Numbers and descriptions here follow the published literature rather than marketing material.
The lyophilized peptide is generally stable for extended periods when kept cold and dry. Once dissolved, aqueous solutions are less stable; hydrolysis, oxidation, and aggregation can degrade the material. Storage at -20 °C or lower slows these processes. Repeated freeze-thaw cycles are best avoided because they can promote aggregation. The exact shelf life depends on formulation, pH, and concentration, so stability studies are typically performed for each specific product.
Quality control for thymosin alpha-1 focuses on identity, purity, and potency. Identity is confirmed by mass spectrometry and amino acid analysis, while purity is assessed by chromatography with limits on related substances and residual solvents. Potency assays may use cell-based immune readouts, but these are not standardized across laboratories. Regulatory status differs by jurisdiction; no product is approved in the United States for clinical use, whereas some other countries register injectable forms for specific indications.
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.
| Property | Value | Notes |
|---|---|---|
| Detection wavelength | 214 nm | Peptide bond absorption; 280 nm is not useful. |
| Confirmatory method | Electrospray mass spectrometry | Verifies mass near 3108 Da. |
| Solution stability | Limited at room temperature | Aqueous solutions degrade faster than powder. |
| Recommended storage | -20 °C | For lyophilized powder; protect from moisture. |
| Purity criterion | ≥95% by RP-HPLC | Typical research-grade specification. |
Identity and purity are assessed mainly by reversed-phase high-performance liquid chromatography, which separates the peptide from closely related impurities and from truncated or oxidized variants. Mass spectrometry supplies the molecular mass and confirms the expected sequence length, while amino acid analysis can be used to check composition. Because the molecule has no chromophore beyond the peptide backbone, ultraviolet detection is typically performed at a low wavelength, where baseline interference from solvents and buffers is a practical concern. Water content and counter-ion content are often reported alongside purity.
Practical handling focuses on limiting adsorption and contamination. The peptide dissolves readily in water, and dilute solutions tend to adhere to plastic and glass surfaces, so an inert carrier protein or a defined buffer can reduce losses in laboratory work. Workers also record the counter-ion form, since an acetate or trifluoroacetate salt changes the mass balance of the weighed powder. Documentation of lot number, purity value, and storage history supports reproducibility when results from different laboratories are compared.
Lyophilized material is generally held at reduced temperature to slow degradation, and storage at minus twenty degrees Celsius or lower is common practice for long-term retention. Short-term working portions are often kept between two and eight degrees Celsius. Once dissolved, the peptide is less stable than the dry powder, and repeated freeze-thaw cycles are associated with loss of material and with aggregate formation. Vials are usually allowed to reach room temperature before opening so that condensation does not introduce moisture, and solutions are protected from light where practical.
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.
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.
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.
== Comparison of somatostatin receptor agonists and antagonists in radiolabelling == Agonists of the somatostatin receptor had been long established as an imaging agent, with the first agonist Ga-DOTATOC coming out in 2001, which is based on a radiolabeled somatostatin receptor agonist drug octreotide, and further developments were based on its structure. Agonists share the characteristic of being uptaken into tumor cells, and degraded intracellularly. Antagonists, while not widely absorbed into the tumor cells, can bind to a wider range of receptors as they can bind to the receptors regardless if the receptors are activated or inactivated. They thus are more sensitive to neuroendocrine tumors. Another study noted the antagonists showed lowered internalization into tumors, cleared from the blood quickly, and had a higher binding to tumors, which were noted to be properties benefitting its use over agonists in detecting metastatic tumors. A head-to-head study of the gallium-containing compounds, where the Ga-NODAGA-JR11 antagonist and Ga-DOTATOC agonist are directly compared, showed that Ga-NODAGA-JR11 had a higher hepatic metastatic tumor detection rate and lesion sensitivity than Ga-DOTATOC. Another head-to-head study of lutetium containing compound found the antagonist Lu-DOTA-JR11 bound with the receptors more quickly, had a longer retention time, and unbound more slowly than the Lu-DOTA-TATE agonist.
In 1958, Korolev upgraded the R-7 to be able to launch a 400-kilogram (880 lb) payload to the Moon. The Luna program began with three failed secret 1958 attempts to launch Luna E-1-class impactor probes. The fourth attempt, Luna 1, launched successfully on January 2, 1959, but missed the Moon. The fifth attempt on June 18 also failed at launch. The 390-kilogram (860 lb) Luna 2 successfully impacted the Moon on September 14, 1959. The 278.5-kilogram (614 lb) Luna 3 successfully flew by the Moon and sent back pictures of its far side on October 7, 1959. The US first embarked on the Pioneer program in 1958 by launching the first probe, albeit ending in failure. A subsequent probe named Pioneer 1 was launched with the intention of orbiting the Moon only to result in a partial mission success when it reached an apogee of 113,800 km before falling back to Earth. The missions of Pioneer 2 and Pioneer 3 failed whereas Pioneer 4 had one partially successful lunar flyby in March 1959.
Perspiration, also known as sweat, diaphoresis and hidrosis, is the fluid secreted by sweat glands in the skin of mammals. Two types of sweat glands can be found in humans: eccrine glands and apocrine glands. The eccrine sweat glands are distributed over much of the body and are responsible for secreting the watery, brackish sweat most often triggered by excessive body temperature. Apocrine sweat glands are restricted to the armpits and a few other areas of the body and produce an odorless, oily, opaque secretion which then gains its characteristic odor from bacterial decomposition. In humans, sweating is primarily a means of thermoregulation, which is achieved by the water-rich secretion of the eccrine glands. Maximum sweat rates of an adult can be up to 2–4 litres (0.5–1 US gal) per hour or 10–14 litres (2.5–3.5 US gal) per day, but is less in children prior to puberty. Evaporation of sweat from the skin surface has a cooling effect due to evaporative cooling. Hence, in hot weather, or when the individual's muscles heat up due to exertion, more sweat is produced. Animals with few sweat glands, such as dogs, accomplish similar temperature regulation results by panting, which evaporates water from the moist lining of the oral cavity and pharynx. Although sweating is found in a wide variety of mammals, relatively few (apart from humans, horses, some primates and some bovidae) produce sweat in order to cool down.
Sources: en.wikipedia.org
=== Environmental influence === It has been suggested that differences in penis size between individuals are caused not only by genetics, but also by environmental factors such as culture, diet and chemical or pollution exposure. Endocrine disruption resulting from chemical exposure has been linked to genital deformation in both sexes (among many other problems). Chemicals from both synthetic (e.g., pesticides, anti-bacterial triclosan, plasticizers for plastics) and natural (e.g., chemicals found in tea tree oil and lavender oil) sources have been linked to various degrees of endocrine disruption. Both PCBs and the plasticizer DEHP have been associated with smaller penis size. DEHP metabolites measured from the urine of pregnant women have been significantly associated with the decreased penis width, shorter anogenital distance and the incomplete descent of testicles of their newborn sons, replicating effects identified in animals. According to a 2008 study published by the US National Library of Medicine, approximately 25% of US women have phthalate levels similar to those observed in animals. Penile size may decrease as a result of some hormonal therapy combined with external beam radiation therapy. In addition, some estrogen-based fertility drugs like diethylstilbestrol (DES) have been linked to genital abnormalities or a smaller than normal penis (microphallus).
== Function == PPARG regulates fatty acid storage and glucose metabolism. The genes activated by PPARG stimulate lipid uptake and adipogenesis by fat cells. PPARG knockout mice are devoid of adipose tissue, establishing PPARG as a master regulator of adipocyte differentiation. PPARG increases insulin sensitivity by enhancing storage of fatty acids in fat cells (reducing lipotoxicity), by enhancing adiponectin release from fat cells, by inducing FGF21, and by enhancing nicotinic acid adenine dinucleotide phosphate production through upregulation of the CD38 enzyme in mice. PPARG promotes anti-inflammatory M2 macrophage activation in mice. Adiponectin induces ABCA1-mediated reverse cholesterol transport by activation of PPAR-γ and LXRα/β. Many naturally occurring agents directly bind with and activate PPAR gamma. These agents include various polyunsaturated fatty acids like arachidonic acid and arachidonic acid metabolites such as certain members of the 5-hydroxyicosatetraenoic acid and 5-oxo-eicosatetraenoic acid family, e.g., 5-oxo-15(S)-HETE and 5-oxo-ETE or 15-hydroxyicosatetraenoic acid family including 15(S)-HETE, 15(R)-HETE, and 15(S)-HpETE, the phytocannabinoid tetrahydrocannabinol (THC), its metabolite THC-COOH, and its synthetic analog ajulemic acid (AJA). The activation of PPAR gamma by these and other ligands may be responsible for inhibiting the growth of cultured human breast, gastric, lung, prostate and other cancer cell lines. During embryogenesis, PPARG first substantially expresses in the interscapular brown fat pad in mice.
=== Singapore === Radiologists in Singapore complete a five-year undergraduate MD program, followed by a one-year internship, and then a five-year residency program. Some radiologists may elect to complete a one or two-year fellowship for further sub-specialization in fields such as interventional radiology. Slovenia After finishing a six-year study of medicine and passing the emergency medicine internship, MDs can apply for radiology residency. Radiology is a five-year post-graduate program that involves all fields of radiology with a final board exam. France To become a radiologist, after having validated the common core of medical studies, one must obtain a DES (Specialized Studies Diploma) in radiology and medical imaging (specialized studies in 5 years), or a DES in advanced interventional radiology (specialized studies in 6 years). At the end of their DES, once validated, the future doctor will have to defend their "practice thesis" to validate their DE (State Diploma) as a doctor of medicine (common to all doctors of medicine, therefore) and to be able to practice in France.
The middle row was almost entirely damaged, although scenes of the Preaching Buddha were identifiable. The panels can be numbered 5 to 9, but 5 and 9 being half-panels going over the adjacent walls. In one of the panels appear soldiers similar to those of the Cave of the Painters. The bottom of the wall contained fragments of panels showing: 10) the Parinirvana, 11) devotees looking at the Buddha being put in a coffin, 11) The Buddha in his coffin, and 12) would have been the Cremation of the Buddha. The upper part of the mural was removed by Grünwedel, and sent to Germany in panels, where some are still held in the Museum für Indische Kunst. This presentation of the various events of the life of the Buddha in successive panels reminds of examples from Gandhara, such as the Sikri stupa, although the panels in the Cave of the Peacock are remarkable by their rigorous chronological arrangement. Similar types of narrative panels have also been found in Andhra. The dome over the cella is composed of eight pairs of segments filled with a flying apsara among peacock feather. Numerous devatas and Buddhas of the past are painted around the dome. According to Historian of Art Benjamin Rowland, commenting one of the remaining fragments, the "group of sword-bearing figures are recognizable Indian ethnic types". Pictures of monks and one Kuchean donor holding a basket of flowers, all labeled with Brahmi inscriptions, appeared on the door wall. In the art of Kizil explanatory labels were often added to pictures of donors.
Sources: en.wikipedia.org
== External links == Deutsch M (17 June 2016). "Guidelines for the Primary and Gender-Affirming Care of Transgender and Gender Nonbinary People" (2nd ed.). University of California, San Francisco: Center of Excellence for Transgender Health. p. 28. Bourns A (2015). "Guidelines and Protocols for Comprehensive Primary Care for Trans Clients" (PDF). Sherbourne Health Centre. Retrieved 15 August 2018. Transgender HRT Research Repository Archived 2022-09-14 at the Wayback Machine
=== Politics === Though considered a political backwater of the federation for much of the 50s and 60s, the 70s saw the ascension of a strong Bosnian political elite. While working within the communist system, politicians such as Džemal Bijedić, Branko Mikulić and Hamdija Pozderac reinforced and protected the sovereignty of Bosnia and Herzegovina. Their efforts proved key during the turbulent period following Tito's death in 1980, and are today considered some of the early steps towards Bosnian independence. However, the republic hardly escaped the increasingly nationalistic climate of the time unscathed. Following the death of Tito in 1980, rising nationalist ideas primarily noted in Serbian academia, pressured Bosnia to deal with allegations of rising nationalism in their own society. One of the most controversial events that were taken by a Bosnian political leadership was a so-called Sarajevo process in 1983 where, under significant pressure from Serbia's political leadership, Bosnian political elite used their influence to secure convictions for several Bosniak nationalists as a type of a political sacrifice to gain political points in the fight against Serbian nationalists. The Sarajevo process centered on convicting Alija Izetbegović for writing "The Islamic Declaration", a literary work which was in the Yugoslav communist regime considered a radical approach towards socialist ideals of former Yugoslavia that were based on suppression of nationalism and any violation of that doctrine was punishable by law.
Other notable mutations identified in ICP patients include ones in the farnesoid X receptor (FXR), a nuclear receptor in hepatocytes which activates transcription of MDR3 and BSEP upon binding intracellular bile acids, thereby increasing canalicular bile efflux.
Sources: en.wikipedia.org
Reverse-phase HPLC with ultraviolet detection at 214 nm is common. Mass spectrometry is used to confirm molecular identity and detect modifications. Immunoassays exist but may not distinguish the intact peptide from fragments.
The lyophilized powder is usually stored at -20 °C or below. Dissolved solutions are less stable and should be prepared fresh when possible. Freeze-thaw cycling can reduce integrity.
It lacks aromatic residues, so it does not absorb strongly at 280 nm. Its negative charge and hydrophilic nature can affect chromatographic retention. These properties require method development for reliable separation.
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.