This is a working overview of freeze-thaw, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-12-25 and is reviewed periodically as new material appears.
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.
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.
Thymosin alpha-1 is a synthetic peptide of 28 amino acid residues that corresponds to a naturally occurring fragment first isolated from thymus tissue. Its chain is acetylated at the amino terminus, a modification that shields the peptide from rapid cleavage by aminopeptidases. The molecule carries a net negative charge at physiological pH and dissolves freely in water. Researchers classify it as an immune-modulating agent rather than a classical hormone, because it acts on several cell types of both the innate and the adaptive immune system.
The peptide was identified during work in the 1970s on thymosin fraction 5, a partially purified extract of calf thymus. Investigators separated that mixture and characterized individual components, one of which they named thymosin alpha-1. The same compound later received the international nonproprietary name thymalfasin. Commercial material is produced by solid-phase peptide synthesis rather than by extraction, so synthetic and natural forms share an identical sequence. Naming conventions vary across the literature, and readers should distinguish the alpha-1 peptide from other thymosins that have unrelated sequences and functions.
| Property | Value | Notes |
|---|---|---|
| Storage of dry powder | -20 °C or below | Common practice for long-term retention |
| Storage after reconstitution | 2-8 °C, short term | Solution stability is limited compared with dry powder |
| Typical analytical method | Reversed-phase HPLC | Usually paired with mass spectrometry for mass confirmation |
| Detection wavelength | About 214 nm | Peptide backbone absorbance; buffer background must be controlled |
| Counter-ion forms | Acetate or trifluoroacetate | Affects mass balance and reported concentration |
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 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.
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.
=== 1980–2009: Expansion globally === As the Japanese economy worsened in the 1980s, Ajinomoto sought to outsource more of its production overseas, which increased the number of employees the company employed overseas from 4,000 in 1979 to more than 11,000 in 1996. Starting in 1980, Ajinomoto began to refocus its diversification efforts from food products to its amino acid business. Following the US FDA's re-approval of aspartame in 1981, Ajinomoto began producing the sweetener at its Tokai factory in 1982. In 1987, Ajinomoto began researching drug development in the fields of clinical nutrition, anti-cancer drugs, infectious diseases, and cardiovascular drugs. Through this research, the company developed ELENTAL for use in clinical nutrition, LIVACT to fight liver disease, and Lentinan in collaboration with the Japanese Foundation for Cancer Research. Ajinomoto later released JINO as a cosmetic and amino acid for athletes, followed by Amino Vital, a supplement to JINO released in 1995. In 2000, Ajinomoto acquired NutraSweet and Euro-Aspartame from Monsanto. In December 1995, Ajinomoto's Philippine CEO and President Leonardo K. Ty was assassinated by two members of the communist guerrilla group Alex Boncayao Brigade. The group cited Ty's allegedly poor safety standards for one of his other companies that they claimed to have led to the deaths of several of his employees. Ty had been head of Union Ajinomoto Inc. with his brother Alejandro since the late 1960s, and prior to his death, Ty had been seeking the protection of the National Bureau of Investigation.
The United Nations Security Council responded swiftly to the killing by later imposing an arms embargo against South Africa. After a period of routine harassment against his family by the authorities, as well as fearing for his life, Woods fled the country after being placed under house arrest by the South African Government. Woods later wrote a book in 1978 entitled Biko, exposing police complicity in his death. That book, along with Woods's autobiography Asking For Trouble, both being published in the United Kingdom, became the basis for the film.
Upon his return from the U.S., Janež introduced the insulin pump method into clinical practice of treating adult patients with type 1 diabetes in Slovenia. Together with his colleagues from the Department of Endocrinology, Diabetes, and Metabolic Disease at University Medical Centre Ljubljana, Janež co-authored the algorithm used in insulin pump treatment, as well as tutored virtually all Slovenian diabetologists in usage of both insulin pump and glucose sensor. Janež also wrote all of the literature on subjects of functional insulin therapy and insulin pump in Slovenia, with its audiences ranging from diabetologists to patients. In 2008, he established a new unit for functional insulin therapy within the University Medical Centre. Janež also led the effort of forming international standards for interpretation of results obtained with glucose sensor, publishing and presenting these on several international diabetes-related symposiums. Coupled with his previous work in the field of functional insulin therapy and its pilot implementation in Slovenia, Janež went on to introduce this approach to diabetes treatment in other countries.
Sources: en.wikipedia.org
=== Erroneous and incomplete discoveries === In 1914, Stefan Meyer, Viktor F. Hess, and Friedrich Paneth (working in Vienna) made measurements of alpha radiation from various substances, including 227Ac. They observed the possibility of a minor alpha branch of this nuclide, though follow-up work could not be done due to the outbreak of World War I. Their observations were not precise and sure enough for them to announce the discovery of element 87, though it is likely that they did indeed observe the decay of 227Ac to 223Fr. Soviet chemist Dmitry Dobroserdov was the first scientist to claim to have found eka-caesium, or francium. In 1925, he observed weak radioactivity in a sample of potassium, another alkali metal, and incorrectly concluded that eka-caesium was contaminating the sample (the radioactivity from the sample was from the naturally occurring potassium radioisotope, potassium-40). He then published a thesis on his predictions of the properties of eka-caesium, in which he named the element russium after his home country. Shortly thereafter, Dobroserdov began to focus on his teaching career at the Polytechnic Institute of Odesa, and he did not pursue the element further. The following year, English chemists Gerald J. F. Druce and Frederick H. Loring analyzed X-ray photographs of manganese(II) sulfate. They observed spectral lines which they presumed to be of eka-caesium. They announced their discovery of element 87 and proposed the name alkalinium, as it would be the heaviest alkali metal.
== External links == Apelin+protein,+human at the U.S. National Library of Medicine Medical Subject Headings (MeSH) "Apelin". IUPHAR Database of Receptors and Ion Channels. International Union of Basic and Clinical Pharmacology. Archived from the original on 2021-08-16. Retrieved 2007-10-25. Human APLN genome location and APLN gene details page in the UCSC Genome Browser.
In Nebraska, the company is affiliated with the Liz's Legacy Cancer Fund "BK Beat Cancer for Kids" program at the UNMC Eppley Cancer Center at the University of Nebraska Medical Center in Omaha. In the Pittsburgh region, it funded the establishment of the Burger King Cancer Caring Center, a support organization for the families and friends of cancer patients.
Early undiagnosed rheumatic diseases such as preclinical rheumatoid arthritis, early stages of inflammatory spondyloarthritis, polymyalgia rheumatica, myofascial pain syndromes and hypermobility syndrome. Neurological diseases that can have important pain and fatigue components include multiple sclerosis, Parkinson's disease and peripheral neuropathy. Other medical illnesses that should be ruled out are endocrine disease or metabolic disorder (hypothyroidism, hyperparathyroidism, acromegaly, vitamin D deficiency), gastro-intestinal disease (celiac and non-celiac gluten sensitivity), infectious diseases (Lyme disease, hepatitis C and immunodeficiency disease) and the early stages of a malignancy such as multiple myeloma, metastatic cancer and leukemia/lymphoma. Other systemic, inflammatory, endocrine, rheumatic, infectious, and neurologic disorders may cause fibromyalgia-like symptoms, such as systemic lupus erythematosus, Sjögren's disease, ankylosing spondylitis, Ehlers-Danlos syndromes, psoriatic-related polyenthesitis, a nerve compression syndrome (such as carpal tunnel syndrome), and myasthenia gravis. Several medications can evoke pain (statins, aromatase inhibitors, bisphosphonates, and opioids).
Sources: en.wikipedia.org
Major Force reappears in Battle for Blüdhaven, a series set a year after the events of Infinite Crisis, as the leader of project S.H.A.D.E. In issue #5, Major Force brutally beats Outsiders member Major Victory and rips off his right arm. He also picks a fight with Hal Jordan, having vowed to kill Green Lanterns on sight after his last encounter with Kyle Rayner. Captain Atom drains Major Force of his energy, leaving him a deflated husk. Major Force is later seen reconstituted and a part of a new regiment of S.H.A.D.E. soldiers. A battle ensues with Uncle Sam and the Freedom Fighters for the soul of America, wherein Major Force is quickly dispatched by Miss America. Major Force later appears as a member of the Secret Society during the wedding of Green Arrow and Black Canary.
=== Pesticides === Although the of lead arsenic-containing pesticides has long been stopped, large areas land remain contaminated. Some arsenic-based pesticides still exist. Chromated copper arsenate has been registered for use in the United States since the 1940s as a wood preservative, protecting wood from insects and microbial agents. In 2003, manufacturers of chromated copper arsenate initiated a voluntary recall of residential wood treated with the chemical. The Environmental Protection Agency Act 2008 final report stated that chromated copper arsenate is still approved for use in nonresidential applications, such as in marine facilities (pilings and structures), utility poles, and sand highway structures.
=== Combinatorial selection of RNA molecules enables in vitro evolution === Experimental methods were invented that allowed investigators to use large, diverse populations of RNA molecules to carry out in vitro molecular experiments that utilized powerful selective replication strategies used by geneticists, and which amount to evolution in the test tube. These experiments have been described using different names, the most common of which are "combinatorial selection", "in vitro selection", and SELEX (for Systematic Evolution of Ligands by Exponential Enrichment). These experiments have been used for isolating RNA molecules with a wide range of properties, from binding to particular proteins, to catalyzing particular reactions, to binding low molecular weight organic ligands. They have equal applicability to elucidating interactions and mechanisms that are known properties of naturally occurring RNA molecules to isolating RNA molecules with biochemical properties that are not known in nature. In developing in vitro selection technology for RNA, laboratory systems for synthesizing complex populations of RNA molecules were established, and used in conjunction with the selection of molecules with user-specified biochemical activities, and in vitro schemes for RNA replication. These steps can be viewed as (a) mutation, (b) selection, and (c) replication. Together, then, these three processes enable in vitro molecular evolution.
Sources: en.wikipedia.org
Cool storage below freezing is usual for long-term retention, with a desiccant and protection from light. Portions are often split before first use to avoid repeated handling.
It is a 28-residue synthetic peptide studied as an immune-modulating agent and approved as a drug in some countries. The sequence matches a naturally occurring fragment isolated from thymus tissue. It is not a hormone in the endocrine sense.
The name traces back to thymosin fraction 5, a crude thymus extract examined in the 1970s. Individual peptides in that mixture were labeled with Greek letters, and alpha-1 was one of them. The international nonproprietary name thymalfasin was assigned later.
No. Thymosin beta-4 contains 43 residues and binds actin, while thymosin alpha-1 contains 28 residues and acts on immune cells. The two sit in a historical naming group but share no sequence similarity, and they are not substitutes for one another.