This is a working overview of research chemical, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-12-15 and is reviewed periodically as new material appears.
TB-500 is a synthetic heptapeptide with the sequence Ac-LKKTETQ. It corresponds to a short N-terminal region of thymosin beta-4, a 43-amino-acid protein found in many cell types. The fragment contains an actin-binding motif, which is one reason it appears in laboratory studies of cell migration and cytoskeletal dynamics. TB-500 is not the full-length protein and is produced as a research chemical rather than an approved therapeutic agent. Its molecular weight is approximately 889 Da.
Several names appear in scientific and commercial contexts for this peptide. The label TB-500 is informal and does not follow standard biochemical nomenclature. Research articles more often describe the compound as a thymosin beta-4 fragment, Tβ4 fragment, or by its sequence Ac-LKKTETQ. Confusing TB-500 with full-length thymosin beta-4 can lead to incorrect assumptions about activity because the fragment lacks the remaining residues of the parent protein. The relationship between fragment and parent protein remains an active area of study.
Regulatory status differs by country, but TB-500 is not an approved pharmaceutical in major jurisdictions. It is commonly sold as a research chemical for laboratory use, which places responsibility for identity and purity on the supplier and the laboratory. Published human data are limited, and most reports involve preclinical models or cell culture. Questions about whether the fragment mimics all actions of thymosin beta-4, and under which conditions, remain open. Independent verification of any material is therefore a practical requirement in research settings.
Biological interest in this peptide centers on its relationship to actin dynamics. Thymosin beta-4 binds monomeric actin through an LKKTET motif, and a short sequence carrying that motif can compete with other actin-binding proteins in cell-free preparations. Investigators propose that such competition shifts the balance between filament assembly and disassembly, which in turn affects how readily a cell extends protrusions and migrates. Most of the supporting observations come from cultured cells and purified protein systems rather than from intact organisms.
Animal work has examined the peptide in models of cardiac injury, skin wounding, and corneal repair, with reported outcomes covering cell migration, inflammatory cell influx, and tissue remodeling. Several of those experiments used the full-length protein or longer fragments instead of the seven-residue sequence, which makes direct comparison between reports difficult. Results are generally described as tissue-dependent, and effect sizes vary considerably across laboratories. Independent replication is uneven, so the overall picture is incomplete rather than settled.
Controlled human trials of the short fragment are scarce. Much of what appears in review articles is extrapolated from animal models or from studies of the parent protein, and literature searches return a larger body of cardiac and ophthalmic work on thymosin beta-4 than on the abbreviated peptide. Regulatory treatment differs by jurisdiction, and in several countries the material is handled as a research chemical rather than an approved therapeutic. Statements about human benefit should be read as provisional.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C38H68N10O14 | Calculated for the acetylated heptapeptide |
| Molecular weight | ~889 Da | Monoisotopic mass approximately 889.0 Da |
| Amino acid sequence | Ac-LKKTETQ | N-terminal acetylated seven-residue peptide |
| Appearance | White to off-white powder | Typically supplied as a lyophilized solid |
| Solubility class | Water-soluble | Peptides of this size generally dissolve in aqueous media |
TB-500 is a research peptide whose sequence matches residues 17 to 23 of thymosin beta-4, a 43-residue protein present in most mammalian cells. The chain is seven amino acids long, written as LKKTETQ, and is normally supplied with an acetyl group on the N-terminus. Suppliers list it as a lyophilised powder under the code name TB-500, and the same sequence appears elsewhere in catalogues as the thymosin beta-4 actin-binding fragment. The label is commercial rather than systematic, so no single authority fixes exactly what TB-500 denotes.
Thymosin beta-4 was isolated from calf thymus in the early 1980s and later characterised as an abundant intracellular actin-sequestering protein. Interest in short synthetic fragments grew once the actin-binding motif had been mapped to the middle of the sequence. TB-500 came out of that line of work as a truncated analogue rather than a natural isolate, and it is now sold mainly to laboratories. Published studies on the fragment have been largely in vitro or in animal models, and controlled human trials remain sparse, so claims about effects in people rest on extrapolation.
TB-500 is a short synthetic peptide sold under a trade name rather than a systematic chemical name. Suppliers usually describe it as a fragment of thymosin beta-4 and ship it as a lyophilised powder intended for laboratory use. Because the label is commercial, the exact sequence attributed to it is not fully consistent across catalogues, and some listings present a seven-residue peptide while others describe related fragments of similar length. It is not an approved medicine in any major jurisdiction, and it is handled as a research chemical.
Thymosin beta-4 itself is a natural peptide of 43 residues found in many cell types and body fluids. Its best-characterised function is binding and sequestering actin monomers, which influences cytoskeletal dynamics. The sequence most often associated with TB-500, LKKTETQ, corresponds to part of that actin-binding region. A different fragment, Ac-SDKP, is also derived from the same parent peptide and is studied in its own right, which is one reason discussions of thymosin fragments can become confusing. The two are structurally distinct and are not interchangeable.
Two franchisees bought the chain in 1984 and they sold out to Inno-Pacific Holdings of Singapore in 1989. By that time, the number of franchises had declined to 221. Most of the remaining U. S. stores closed during the time Inno-Pacific owned the chain. Some of the remaining franchisees took Inno-Pacific to court in 2003. Before the case could come to trial, Shakey's was sold to Jacmar Companies of Alhambra, California in 2004. Jacmar had been the franchisee of 19 Shakey's restaurants. On September 30, 2024, SPAVI announced the incorporation of an American subsidiary that would own and operate and franchise stores in the United States. As of October 2018, there were 51 Shakey's Pizza restaurants in the United States - 48 of the locations are in California (all, except Oroville, are in Southern California), and two in Washington. The last location east of the Mississippi River, in Auburn, Alabama, closed in April 2019. The location in Renton, Washington closed on January 20, 2025, leaving Pasco as the only remaining Washington location. All locations closed their dining rooms in mid-March 2020 to combat the COVID-19 pandemic, with take-out service still available. Dining rooms re-opened in May 2021.
=== SNPs === ERAP1 is a polymorphic gene that has many single nucleotide variants (SNVs) including several common missense variants that alter the ERAP1 amino acid sequence. The various combinations of common SNVs in ERAP1 organize into distinct haplotypes that encode different protein isoforms often referred to as "allotypes". The allotypes of ERAP1 can broadly be categorized based on their enzymatic activity ranging from "high" to "low". The enzymatic activity of ERAP1 is dependent on substrate recognition of the peptide, seen by the trimming efficiency of specific peptide substrates varying significantly for a given allotype. As is the case for allotype 10, a poor trimming allotype, shown to be tenfold less active compared to the ancestral allotype in hydrolysis of the substrate l-leucine-7-amido-4-methylcoumarin (Leu-AMC).
Atoms were thought to be the smallest possible division of matter until 1899 when J. J. Thomson discovered the electron through his work on cathode rays. A Crookes tube is a sealed glass container in which two electrodes are separated by a vacuum. When a voltage is applied across the electrodes, cathode rays are generated, creating a glowing patch where they strike the glass at the opposite end of the tube. Through experimentation, Thomson discovered that the rays could be deflected by electric fields and magnetic fields, which meant that these rays were not a form of light but were composed of very light charged particles, and their charge was negative. Thomson called these particles "corpuscles". He measured their mass-to-charge ratio to be several orders of magnitude smaller than that of the hydrogen atom, the smallest atom. This ratio was the same regardless of what the electrodes were made of and what the trace gas in the tube was. In contrast to those corpuscles, positive ions created by electrolysis or X-ray radiation had mass-to-charge ratios that varied depending on the material of the electrodes and the type of gas in the reaction chamber, indicating they were different kinds of particles. In 1898, Thomson measured the charge on ions to be roughly 6 × 10−10 electrostatic units (2 × 10−19 Coulombs).
Sources: en.wikipedia.org
=== Background === Banki's family lived in Iran and through the early 2000s with his parents' marriage falling apart, the family decided to send a portion of the family assets to the US. Between 2006 and 2009 Banki's family sent proceeds of his parents' divorce settlement (approximately $3.4 million) to him, from Iran to the US. The money came into a single bank account at Bank of America, over multiple transfers through an informal money transfer systems which the defendant argued was legal and the only means of sending money out of Iran at the time. Banki used the majority of this money to purchase an apartment in downtown Manhattan. Prosecutors argued that over this three-year period Banki had violated the sanctions imposed by the US on Iran. The indictment accused Banki of violating the sanctions law, running an informal underground bank, and helping "manage, supervise, operate, and conduct" an unlicensed money transmittal service through which he directly or indirectly facilitated and violated the Iran sanctions. In essence, the charges against Banki stemmed from prosecution allegations that he, as an American citizen, had violated US sanctions on Iran.
β-Carbolines and harmala alkaloids like harmine and harmaline contain DMT's close analogue NMT embedded in their structures. Triptans like sumatriptan, rizatriptan, eletriptan, almotriptan, frovatriptan, and zolmitriptan, which are antimigraine agents, all contain DMT in their structures. Similarly, the pertine antipsychotics including alpertine, milipertine, oxypertine, and solypertine are DMT derivatives. Bioisosteres of DMT in which the indole ring system has been replaced with a different ring system include isoDMT (an isoindole or isotryptamine), 2ZEDMA (an indolizine), and C-DMT (an indene), among others. The homologues of DMT in which the alkyl side chain has been shortened or lengthened by one carbon atom are gramine and dimethylhomotryptamine (DMHT), respectively. Further-extended homologues are also known. Deuterated isotopologues of DMT include deudimethyltryptamine (DMT-d10) or CYB004 (HLP004), SPL028 (D2-DMT; α,α-dideutero-DMT), and DMT-d4 (α,α,β,β-tetradeutero-DMT). Prodrugs of DMT such as 1-benzoyl-DMT and N-phosphonooxymethyl-DMT (N-POM-DMT) have also been described. Many of DMT's analogues and derivatives are serotonin receptor modulators and/or serotonergic psychedelics similarly to DMT itself.
Produced by Robert Eagle, directed by Patrick Fleming, made by Eagle & Eagle, with The Learning Channel. Shown on TLC in 1999 20 September Do Parents Matter?, about the psychological needs of children; the psychiatrist Stanley Greenspan; the book The Nurture Assumption by Judith Rich Harris argued that a child's associates shaped their personality, as seen most commonly in their teenage years; teenage subdivisions in the USA - the 'populars' and the 'jocks'; at university, Judith Harris had her study stopped by the famous psychology academic George Armitage Miller; Thomas J. Bouchard Jr. at the University of Minnesota and his study of separated identical twins and the effect of genes, which he estimated to be around 50%; the effect of the home was thought to account for the other 50%, but psychologists did not find anything like that; work by psychologist Carolyn Rovee-Collier; primatology and work by Frans de Waal; childhood studies by William Corsaro influenced findings; the 'normals' teenage subdivision; the 1953 Asch conformity experiments on teenagers by psychologist Solomon Asch, with five stooges in a group of six teenagers that would often exert group influence over the sixth teenager, helped findings; a similar effect was deployed in the Candid Camera series, to convince people; the 'skaters' teenage subdivision; further studies on conformity in the Stanford prison experiment of 1971 by Philip Zimbardo - the BBC made the 2002 documentary The Experiment; the 'loners' teenage subdivision.
Sources: en.wikipedia.org
3-Allylfentanyl is an opioid analgesic that is an analogue of fentanyl. 3-Allylfentanyl has effects similar to fentanyl, although it is only 0.13x-0.14x as potent by weight. The decreased potency of this analogue caused by the addition of the allyl group makes it somewhat less dangerous than fentanyl itself (ED50(rat) of 80μg/kg vs 11μg/kg for fentanyl), although this is relative. For comparison, carfentanil is at least 20-30x as potent as fentanyl.
Neopentalenolactone D synthase (EC 1.14.13.171, ptlE (gene)) is an enzyme with systematic name 1-deoxy-11-oxopentalenate,NADH:oxygen oxidoreductase (neopentalenolactone-D forming). This enzyme catalyses the following chemical reaction
In 2007, Waffle House repurchased the original restaurant, which had been sold by the chain in the early 1970s. The company restored it using original blueprints for use as a private company museum. The museum is used primarily for internal corporate events and tours. In 2008, one of the biggest Waffle House franchises in the southeast, North Lake Foods, was bought out by Waffle House, Inc. North Lake Foods filed for Chapter 11 bankruptcy protection and closed some stores. Waffle House, Inc. plans to rehabilitate the franchise. In early 2009, East Coast Waffles bought North Lake Foods to become a new franchise. The founders of the Waffle House brand died in 2017 within two months of each other: Joe Rogers Sr. died on March 3 and Tom Forkner on April 26. On September 8, 2024, it was reported that Walter G. Ehmer, who oversaw Waffle House since 2012, had died. In 2025, Waffle House introduced canned cold brew as a new "all-star" to its lineup as a limited run in nine locations, all of which are in Atlanta.
Sources: en.wikipedia.org
TB-500 is a synthetic heptapeptide corresponding to a fragment of thymosin beta-4. It is used in laboratory research and is not an approved drug.
No. Thymosin beta-4 is a 43-amino-acid protein, while TB-500 represents only a short N-terminal segment. The two should not be treated as interchangeable in experimental design.
It is often called a thymosin beta-4 fragment, Tβ4 fragment, or Ac-LKKTETQ. The name TB-500 is mainly a commercial or catalog label rather than a formal chemical name.
The leading proposal involves sequestration of monomeric actin, which would alter cytoskeletal turnover and cell movement. The actin-binding motif shared with the parent protein is central to that idea. Direct confirmation in whole organisms remains limited.