solid-phase synthesis raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-06-11 and is reviewed periodically as new material appears.
The molecule consists of 28 amino acid residues with an acetyl group attached to the N-terminal serine. Its sequence is acidic overall, with several glutamic and aspartic acid residues distributed along the chain and no cysteine, so disulfide bridges do not form. The peptide carries a net negative charge at physiological pH. Because the N-terminus is blocked, the intact molecule resists degradation by many aminopeptidases, which contributes to its stability in biological fluids.
The peptide is generated in cells by cleavage of prothymosin alpha, a larger acidic protein encoded by the PTMA gene. Prothymosin alpha is expressed in many tissues, not only in the thymus, and its functions include nuclear roles in chromatin-related processes. The 28-residue fragment corresponds to the N-terminal portion of that precursor. How the cleavage occurs and how the fragment's concentration is regulated remain open questions; circulating amounts are small and difficult to measure reliably with routine assays.
The peptide was described in the 1970s as a component of thymic extracts, and early research focused on restoring immune function in immunodeficiency states. A synthetic version entered clinical development in the 1980s and is approved as a drug in several countries for conditions such as chronic hepatitis B and certain immunodeficiencies. Approval status varies widely by jurisdiction, and in the United States it is not an approved therapeutic. Regulatory and clinical positions differ, so statements about efficacy should be tied to specific indications and studies.
Thymosin alpha-1 is a synthetic peptide of 28 amino acids, corresponding to the N-terminal fragment of prothymosin alpha. Its sequence begins with acetylation at the N-terminus, a modification that affects stability and receptor interaction. The peptide is acidic, with a calculated isoelectric point near 4.2, and carries no disulfide bonds, so its secondary structure is largely flexible in solution. Molecular mass is approximately 3108 daltons. The native form was first isolated from bovine thymus tissue, while pharmaceutical material is produced by solid-phase peptide synthesis.
Within the immune system, the peptide acts on several cell types rather than a single target. Reported activities include promotion of T-cell maturation, enhancement of natural killer cell activity, and modulation of cytokine production by dendritic cells and macrophages. Some of these effects appear to operate through toll-like receptor signaling, though the precise receptor-level mechanism remains debated. Whether the observed immune changes translate into clinical benefit is a separate question and depends on the indication studied.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Acetylated peptide | N-terminal acetyl group blocks aminopeptidase attack |
| Residue count | 28 amino acids | Matches the N-terminus of prothymosin alpha |
| Molecular mass | About 3,108 Da | Value for the free, unmodified peptide |
| Isoelectric point | Approximately 4.2 | Acidic; net negative charge at neutral pH |
| Encoding gene | PTMA | Human gene for the precursor protein |
Biologically, the peptide is studied mainly in the context of immune cell development and regulation. It is produced in the thymus and in several other tissues, and it appears to influence the maturation and activity of T cells and other immune populations. Laboratory work describes effects on cytokine production, on the balance between T cell subsets, and on the function of dendritic cells. Much of this evidence comes from cell culture and animal models, so the extent to which the same pathways operate in humans remains an open question.
Clinical interest has centered on chronic viral hepatitis, on immune restoration in various conditions, and on use as an adjuvant intended to improve responses to vaccines. Trials have reported mixed results, and regulatory status differs sharply between countries; in some places it is a prescription product, while elsewhere it is sold without an approved therapeutic indication. Because published studies vary widely in design, population, and endpoints, comparisons across them are difficult and no single conclusion covers the whole literature.
Thymosin alpha 1 was identified in 1977 as a component of thymosin fraction 5, a heterogeneous preparation used in early studies of thymic function. Investigators purified the active material and determined its amino acid sequence, which enabled chemical synthesis. Work in the following decades concentrated on T-cell maturation and immune reconstitution in animals and small human cohorts. Early preparations varied in composition, so results from that period are difficult to compare with studies using defined synthetic peptide.
Clinical research has examined the peptide in chronic hepatitis B and C, as a vaccine adjuvant, and in sepsis and oncology settings. Findings across trials are mixed; some report changes in selected immune markers, while others find no clear clinical benefit. Many studies are small and define outcomes differently, which limits comparison. Regulatory approval is confined to a few countries, and the compound is not an approved drug in the United States or most of Europe.
Acrokeratoelastoidosis of Costa (keratoelastoidosis marginalis) Aquagenic keratoderma (acquired aquagenic palmoplantar keratoderma, aquagenic syringeal acrokeratoderma, aquagenic wrinkling of the palms, transient reactive papulotranslucent acrokeratoderma) Bart–Pumphrey syndrome (palmoplantar keratoderma with knuckle pads and leukonychia and deafness) Camisa disease Carvajal syndrome (striate palmoplantar keratoderma with woolly hair and cardiomyopathy, striate palmoplantar keratoderma with woolly hair and left ventricular dilated cardiomyopathy) Corneodermatoosseous syndrome (CDO syndrome) Diffuse epidermolytic palmoplantar keratoderma (palmoplantar keratoderma cum degeneratione granulosa Vörner, Vörner's epidermolytic palmoplantar keratoderma, Vörner keratoderma) Diffuse nonepidermolytic palmoplantar keratoderma (diffuse orthohyperkeratotic keratoderma, hereditary palmoplantar keratoderma, keratosis extremitatum progrediens, keratosis palmoplantaris diffusa circumscripta, tylosis, Unna–Thost disease, Unna–Thost keratoderma) Erythrokeratodermia variabilis (erythrokeratodermia figurata variabilis, keratosis extremitatum progrediens, keratosis palmoplantaris transgrediens et progrediens, Mendes da Costa syndrome, Mendes da Costa type erythrokeratodermia, progressive symmetric erythrokeratoderma) Focal acral hyperkeratosis (acrokeratoelastoidosis lichenoides, degenerative collagenous plaques of the hand) Focal palmoplantar and gingival keratosis Focal palmoplantar keratoderma with oral mucosal hyperkeratosis (focal epidermolytic palmoplantar keratoderma, hereditary painful callosities, hereditary painful callosity syndrome, keratosis follicularis, keratosis palmoplantaris nummularis, nummular epidermolytic palmoplantar keratoderma) Haim–Munk syndrome (palmoplantar keratoderma with periodontitis and arachnodactyly and acro-osteolysis) Hidrotic ectodermal dysplasia (alopecia congenita with keratosis palmoplantaris, Clouston syndrome, Clouston's hidrotic ectodermal dysplasia, Fischer–Jacobsen–Clouston syndrome, keratosis palmaris with drumstick fingers, palmoplantar keratoderma and clubbing) Howel–Evans syndrome (familial keratoderma with carcinoma of the esophagus, focal non-epidermolytic palmoplantar keratoderma with carcinoma of the esophagus, palmoplantar ectodermal dysplasia type III, palmoplantar keratoderma associated with esophageal cancer, tylosis, tylosis–esophageal carcinoma) Hystrix-like ichthyosis–deafness syndrome (HID syndrome) Keratoderma climactericum (acquired plantar keratoderma, climacteric keratoderma, Haxthausen's disease) Keratosis punctata palmaris et plantaris (Buschke–Fischer–Brauer disease, Davis Colley disease, keratoderma disseminatum palmaris et plantaris, keratosis papulosa, keratoderma punctatum, keratodermia punctata, keratoma hereditarium dissipatum palmare et plantare, palmar and plantar seed dermatoses, palmar keratoses, papulotranslucent acrokeratoderma, punctate keratoderma, punctate keratoses of the palms and soles, maculosa disseminata) Keratitis–ichthyosis–deafness syndrome (erythrokeratodermia progressiva Burns, ichthyosiform erythroderma with corneal involvement and deafness, KID syndrome) Mal de Meleda (acral keratoderma, Gamborg–Nielsen keratoderma, mutilating palmoplantar keratoderma of the Gamborg–Nielsen type, palmoplantar ectodermal dysplasia type VIII, palmoplantar keratoderma of the Norrbotten type) Naxos syndrome (diffuse non-epidermolytic palmoplantar keratoderma with woolly hair and cardiomyopathy, diffuse palmoplantar keratoderma with woolly hair and arrythmogenic right ventricular cardiomyopathy of Naxos, Naxos disease) Olmsted syndrome (mutilating palmoplantar keratoderma with periorificial keratotic plaques, mutilating palmoplantar keratoderma with periorificial plaques, polykeratosis of Touraine) Pachyonychia congenita type I (Jadassohn–Lewandowsky syndrome) Pachyonychia congenita type II (Jackson–Lawler pachyonychia congenita, Jackson–Sertoli syndrome) Palmoplantar keratoderma and spastic paraplegia (Charcot–Marie–Tooth disease with palmoplantar keratoderma and nail dystrophy) Palmoplantar keratoderma of Sybert (Greither palmoplantar keratoderma, Greither syndrome, keratosis extremitatum hereditaria progrediens, keratosis palmoplantaris transgrediens et progrediens, Sybert keratoderma, transgrediens and progrediens palmoplantar keratoderma) Papillon–Lefèvre syndrome (palmoplantar keratoderma with periodontitis) Porokeratosis plantaris discreta Punctate palmoplantar keratoderma Schöpf–Schulz–Passarge syndrome (eyelid cysts with palmoplantar keratoderma and hypodontia and hypotrichosis) Scleroatrophic syndrome of Huriez (Huriez syndrome, palmoplantar keratoderma with scleroatrophy, palmoplantar keratoderma with sclerodactyly, scleroatrophic and keratotic dermatosis of the limbs, sclerotylosis) Striate palmoplantar keratoderma (acral keratoderma, Brünauer–Fuhs–Siemens type of palmoplantar keratoderma, focal non-epidermolytic palmoplantar keratoderma, keratosis palmoplantaris varians, palmoplantar keratoderma areata, palmoplantar keratoderma striata, Wachter keratoderma, Wachters palmoplantar keratoderma) Spiny keratoderma (porokeratosis punctata palmaris et plantaris, punctate keratoderma, punctate porokeratosis of the palms and soles) Tyrosinemia type II (oculocutaneous tyrosinemia, Richner–Hanhart syndrome) Vohwinkel syndrome (keratoderma hereditaria mutilans, keratoma hereditaria mutilans, mutilating keratoderma of Vohwinkel, mutilating palmoplantar keratoderma)
Glucokinase is a monomeric protein of 465 amino acids and a molecular weight of about 50 kDa. There are at least two clefts, one for the active site, binding glucose and MgATP, and the other for a putative allosteric activator that has not yet been identified. This is about half the size of the other mammalian hexokinases, which retain a degree of dimeric structure. Several sequences and the three-dimensional structure of the key active sites are highly conserved both in intra-species homologs and across species from mammals to yeast. The ATP binding domain, for example, are shared with hexokinases, bacterial glucokinases, and other proteins, and the common structure is termed an actin fold.
==== Lip biopsy ==== A lip/salivary gland biopsy takes a tissue sample that can reveal lymphocytes clustered around salivary glands, and damage to these glands from inflammation. This test involves removing a tissue sample from a person's inner lip/salivary gland and examining it under a microscope. On such biopsies, the single most important test result in the diagnosis of the oral component of Sjögren’s is likely the focus score, which is the number of mononuclear cell infiltrates containing at least 50 inflammatory cells in a 4 mm2 glandular section. The Chisholm-Mason grades are also widely used for salivary gland biopsies (see table).
Guillermo Uribe Holguín, an important cultural figure in the National Symphony Orchestra of Colombia, Luis Antonio Calvo and Blas Emilio Atehortúa are some of the greatest exponents of the art music. The Bogotá Philharmonic Orchestra is one of the most active orchestras in Colombia. Caribbean music has many vibrant rhythms, such as cumbia (it is played by the maracas, the drums, the gaitas and guacharaca), porro (it is a monotonous but joyful rhythm), mapalé (with its fast rhythm and constant clapping) and the "vallenato", which originated in the northern part of the Caribbean coast (the rhythm is mainly played by the caja, the guacharaca, and accordion). The music from the Pacific coast, such as the currulao, is characterized by its strong use of drums (instruments such as the native marimba, the conunos, the bass drum, the side drum, and the cuatro guasas or tubular rattle). An important rhythm of the south region of the Pacific coast is the contradanza (it is used in dance shows due to the striking colours of the costumes). Marimba music, traditional chants and dances from the Colombia South Pacific region are on UNESCO's Representative List of the Intangible Cultural Heritage of Humanity.
In steady state, Grx2 forms dimers to coordinate iron-sulfur clusters, which in turn inactivate Grx2's activity by sequestering the active-site cysteines. During oxidative stress, the dimers separate into iron-free active monomers, which restore Grx2's activity.
Sources: en.wikipedia.org
On the other hand, other than the lightest nuclides, nuclides with an odd number of protons and an odd number of neutrons (odd Z, odd N) are usually short-lived (a notable exception is neptunium-236 with a half-life of 154,000 years) because they readily decay by beta-particle emission to their isobars with an even number of protons and an even number of neutrons (even Z, even N) becoming much more stable. The physical basis for this phenomenon also comes from the pairing effect in nuclear binding energy, but this time from both proton–proton and neutron–neutron pairing. The relatively short half-life of such odd-odd heavy isotopes means that they are not available in quantity and are highly radioactive. According to the fissility rule proposed by Yigal Ronen, for a heavy element with Z between 90 and 100, an isotope is fissile if and only if 2 × Z − N ∈ {41, 43, 45} (where N = number of neutrons and Z = number of protons), with a few exceptions. This rule holds for all but fourteen nuclides – seven that satisfy the criterion but are nonfissile, and seven that are fissile but do not satisfy the criterion.
The cecum is a pouch marking the division between the small intestine and the large intestine. It lies below the ileocecal valve in the lower right quadrant of the abdomen. The cecum receives chyme from the last part of the small intestine, the ileum, and connects to the ascending colon of the large intestine. At this junction there is a sphincter or valve, the ileocecal valve which slows the passage of chyme from the ileum, allowing further digestion. It is also the site of the appendix attachment.
Taihō had just launched 42 aircraft as a part of the second raid when Albacore fired the torpedo spread. Of the six torpedoes fired, four veered off-target. Japanese pilot Sakio Komatsu had recently launched and from his aircraft sighted one of the two torpedoes which were heading for Taihō. Komatsu dived into the path of the torpedo which then detonated. The sixth torpedo struck the carrier on her starboard side and ruptured two aviation fuel tanks. The carrier's escorting destroyers made depth charge attacks but caused only minor damage to Albacore. Initially, the damage to Taihō seemed minor; the flooding was quickly contained and the carrier's propulsion and navigation were unaffected. Taihō quickly resumed regular operations, but gasoline vapor from the ruptured fuel tanks began to fill the hangar decks, creating an increasingly dangerous situation on board.
== National laws, regulations, and management == Laws governing aquaculture practices vary greatly by country and are often not closely regulated or easily traceable. In the United States, land-based and nearshore aquaculture is regulated at the federal and state levels; no national laws govern offshore aquaculture in U.S. exclusive economic zone waters. In June 2011, the Department of Commerce and National Oceanic and Atmospheric Administration released national aquaculture policies to address this issue and "to meet the growing demand for healthy seafood, to create jobs in coastal communities, and restore vital ecosystems." Large aquaculture facilities (i.e. those producing 20,000 pounds (9,100 kg) per year) which discharge wastewater are required to obtain permits pursuant to the Clean Water Act. Facilities that produce at least 100,000 pounds (45,000 kg) of fish, molluscs or crustaceans a year are subject to specific national discharge standards. Other permitted facilities are subject to effluent limitations that are developed on a case-by-case basis.
Sources: en.wikipedia.org
Thymosin fraction 5 is a mixture of many peptides obtained from thymus tissue, while thymosin alpha 1 is a single defined 28-residue molecule. The two names appear together in older literature because the purified peptide was first obtained from that mixture.
The precursor, prothymosin alpha, is encoded by the PTMA gene in humans. The 28-residue peptide corresponds to the N-terminal segment released from that larger protein.
It is produced as a fragment of prothymosin alpha and is present in many tissues. Circulating concentrations are low, which makes routine measurement difficult.
It corresponds to a fragment of the larger protein prothymosin alpha, which is present in many tissues. The isolated 28-amino-acid peptide was originally obtained from thymus preparations, and the pharmaceutical product is synthesized rather than extracted. The term therefore describes both a natural fragment and a manufactured drug substance.