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Thymosin Beta-4 Fragment Identity — Common Mistakes

By Editorial Desk · published 2025-09-12 · last reviewed 2025-10-02 · Guide

This is a working overview of heptapeptide, written for readers who want more than a one-paragraph summary but less than a textbook.

Reviewed 2025-10-02. Anything still debated is marked as such rather than presented as settled.

Thymosin Beta-4 Fragment Identity

No major regulatory agency has approved TB-500 for therapeutic use, and it holds no pharmacopoeial monograph. The name appears on the World Anti-Doping Agency prohibited list within the class covering peptide hormones, growth factors, and related substances. Detection in doping control relies on mass spectrometric methods applied to urine, often after preparation steps that concentrate the analyte. Discussion of TB-500 therefore clusters in biochemistry, sports medicine, and anti-doping literature rather than in registered clinical trials.

TB-500 is a synthetic peptide preparation marketed under a name derived from thymosin beta-4, a 43-residue actin-binding protein first isolated from thymus tissue. The full-length protein has a reported molecular mass near 4963 Da, while material sold as TB-500 is often described as a fragment containing the actin-binding motif LKKTETQ. Because suppliers use the name inconsistently, published sources sometimes refer to the same label as a fragment, a synthetic copy, or a related analog. This naming ambiguity complicates direct comparison of reports across studies.

TB-500 Background and Identity

Research interest in thymosin beta-4 fragments centres on actin sequestration, cell migration and tissue repair models. Most published work uses cultured cells or animal wound and cardiac preparations, and findings are generally described as preliminary. No fragment of this protein has been approved as a therapeutic product by major regulators. Reviews of the field note inconsistent dosing, delivery routes and outcome measures across studies, which complicates direct comparison. The material is best understood as a laboratory reagent with an active but unresolved research literature.

TB-500 is a catalogue name applied to a synthetic peptide related to thymosin beta-4, an actin-binding protein found in most mammalian cells. Suppliers do not use the label consistently: some describe it as the full 43-residue protein, others as a short fragment from the actin-binding region, and others as a related tetrapeptide. Because the name is commercial rather than chemical, two products sold under it may not contain the same molecule. This naming ambiguity is the first point to check in any description of the material.

The most frequently cited identity is a seven-residue fragment with the sequence LKKTETQ, taken from the actin-binding domain of the parent protein. A separate molecule, N-acetyl-seryl-aspartyl-lysyl-proline, often shortened to Ac-SDKP, derives from the same protein's N-terminal region and appears in overlapping literature. Reported molecular masses therefore differ between sources, and a mass value on its own does not establish which fragment is present. Confirmation requires a defined sequence rather than a single number.

Tb-500 at a glance

PropertyValueNotes
Molecular massApproximately 4963 Da for full-length thymosin beta-4Value applies to the parent protein; fragment products may differ
AppearanceWhite to off-white lyophilized powderTypical form of supplied synthetic peptide
SolubilityFreely soluble in waterPolar peptide; dissolves readily in aqueous buffer
Storage of dry powder−20 °C, desiccated, protected from lightStandard laboratory practice for peptides
Typical detection methodLiquid chromatography–tandem mass spectrometryUsed in purity testing and anti-doping analysis

TB-500 Identity and Naming Background

Interest in the fragment grew during the 1990s and 2000s, when it moved from laboratory work into sports and supplement markets. Anti-doping bodies added thymosin beta-4 fragments to prohibited lists, and a small number of adverse analytical findings have been reported in competition testing. Published controlled human trials remain scarce. Most mechanistic evidence comes from cell culture and animal models, and those studies examine endpoints such as cell migration, wound closure and inflammation markers. That evidence supports research interest but does not establish clinical benefit, and broad regenerative claims should be read as unverified.

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.

Related pages on this site

TB-500 Identity and Molecular Background

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.

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.

Identity and Research Background

TB-500 is a synthetic seven-amino-acid peptide with the sequence LKKTETQ, corresponding to residues 17 through 23 of the protein thymosin beta-4. The N-terminus is typically acetylated in the described form, giving a monoisotopic mass near 888.5 Da and an average mass of about 889 Da. The designation TB-500 is a catalogue label rather than a formal chemical name, and the same sequence appears in the literature under several alternative abbreviations. It is handled as a research reagent rather than a pharmaceutical product.

Thymosin beta-4 is a 43-residue actin-binding protein found in most mammalian cell types, where it participates in cytoskeletal regulation and cell migration. TB-500 represents only a short fragment of that protein and does not include the remaining residues. Whether the isolated fragment reproduces the full range of activities reported for the intact protein remains an open question. Researchers commonly treat the two as related but distinct entities when comparing results.

Supporting material

=== EC 2.4.1: Hexosyltransferases === EC 2.4.1.1: Glycogen phosphorylase EC 2.4.1.2: dextrin dextranase EC 2.4.1.3: deleted, included in EC 2.4.1.25 EC 2.4.1.4: amylosucrase EC 2.4.1.5: dextransucrase EC 2.4.1.6: deleted EC 2.4.1.7: sucrose phosphorylase EC 2.4.1.8: maltose phosphorylase EC 2.4.1.9: inulosucrase EC 2.4.1.10: levansucrase EC 2.4.1.11: glycogen(starch) synthase EC 2.4.1.12: cellulose synthase (UDP-forming) EC 2.4.1.13: sucrose synthase EC 2.4.1.14: sucrose-phosphate synthase EC 2.4.1.15: α,α-trehalose-phosphate synthase (UDP-forming) EC 2.4.1.16: chitin synthase EC 2.4.1.17: glucuronosyltransferase EC 2.4.1.18: ,4-α-glucan branching enzyme EC 2.4.1.19: cyclomaltodextrin glucanotransferase EC 2.4.1.20: cellobiose phosphorylase EC 2.4.1.21: starch synthase EC 2.4.1.22: lactose synthase EC 2.4.1.23: sphingosine β-galactosyltransferase EC 2.4.1.24: 1,4-α-glucan 6-α-glucosyltransferase EC 2.4.1.25: 4-α-glucanotransferase EC 2.4.1.26: DNA α-glucosyltransferase EC 2.4.1.27: DNA β-glucosyltransferase EC 2.4.1.28: glucosyl-DNA β-glucosyltransferase EC 2.4.1.29: cellulose synthase (GDP-forming) EC 2.4.1.30: 1,3-β-oligoglucan phosphorylase EC 2.4.1.31: laminaribiose phosphorylase EC 2.4.1.32: glucomannan 4-β-mannosyltransferase EC 2.4.1.33: mannuronan synthase EC 2.4.1.34: 1,3-β-glucan synthase EC 2.4.1.35: phenol β-glucosyltransferase EC 2.4.1.36: α,α-trehalose-phosphate synthase (GDP-forming) EC 2.4.1.37: fucosylgalactoside 3-α-galactosyltransferase EC 2.4.1.38: β-N-acetylglucosaminylglycopeptide β-1,4-galactosyltransferase EC 2.4.1.39: steroid N-acetylglucosaminyltransferase EC 2.4.1.40: glycoprotein-fucosylgalactoside α-N-acetylgalactosaminyltransferase EC 2.4.1.41: polypeptide N-acetylgalactosaminyltransferase EC 2.4.1.42: deleted, included in EC 2.4.1.17 EC 2.4.1.43: polygalacturonate 4-α-galacturonosyltransferase EC 2.4.1.44: lipopolysaccharide 3-α-galactosyltransferase EC 2.4.1.45: now included with EC 2.4.1.47, N-acylsphingosine galactosyltransferase EC 2.4.1.46: monogalactosyldiacylglycerol synthase EC 2.4.1.47: N-acylsphingosine galactosyltransferase EC 2.4.1.48: heteroglycan α-mannosyltransferase EC 2.4.1.49: cellodextrin phosphorylase EC 2.4.1.50: procollagen galactosyltransferase EC 2.4.1.51: now covered by EC 2.4.1.101, EC 2.4.1.143, EC 2.4.1.144 and EC 2.4.1.145 EC 2.4.1.52: poly(glycerol-phosphate) α-glucosyltransferase EC 2.4.1.53: poly(ribitol-phosphate) β-glucosyltransferase EC 2.4.1.54: undecaprenyl-phosphate mannosyltransferase EC 2.4.1.55: Now EC 2.7.8.14, CDP-ribitol ribitolphosphotransferase EC 2.4.1.56: lipopolysaccharide N-acetylglucosaminyltransferase EC 2.4.1.57: Newer studies have shown that this is catalysed by two independent activities now covered by EC 2.4.1.345, phosphatidyl-myo-inositol α-mannosyl transferase and EC 2.4.1.346, phosphatidyl-myo-inositol dimannoside synthase EC 2.4.1.58: lipopolysaccharide glucosyltransferase I EC 2.4.1.59: deleted, included in EC 2.4.1.17 EC 2.4.1.60: CDP-abequose:α-D-Man-(1→4)-α-L-Rha-(1→3)-α-D-Gal-PP-Und α-1,3-abequosyltransferase EC 2.4.1.61: deleted, included in EC 2.4.1.17 EC 2.4.1.62: ganglioside galactosyltransferase EC 2.4.1.63: linamarin synthase EC 2.4.1.64: α,α-trehalose phosphorylase EC 2.4.1.65: 3-galactosyl-N-acetylglucosaminide 4-α-L-fucosyltransferase EC 2.4.1.66: procollagen glucosyltransferase EC 2.4.1.67: galactinol—raffinose galactosyltransferase EC 2.4.1.68: glycoprotein 6-α-L-fucosyltransferase EC 2.4.1.69: type 1 galactoside α-(1,2)-fucosyltransferase EC 2.4.1.70: poly(ribitol-phosphate) α-N-acetylglucosaminyltransferase EC 2.4.1.71: arylamine glucosyltransferase EC 2.4.1.72: now EC 2.4.2.24, 1,4-β-D-xylan synthase EC 2.4.1.73: lipopolysaccharide glucosyltransferase II EC 2.4.1.74: glycosaminoglycan galactosyltransferase EC 2.4.1.75: deleted entry, insufficient evidence to conclude that this is a different enzyme from EC 2.4.1.43 EC 2.4.1.76: deleted, included in EC 2.4.1.17 EC 2.4.1.77: deleted, included in EC 2.4.1.17 EC 2.4.1.78: phosphopolyprenol glucosyltransferase EC 2.4.1.79: globotriaosylceramide 3-β-N-acetylgalactosaminyltransferase EC 2.4.1.80: ceramide glucosyltransferase EC 2.4.1.81: flavone 7-O-β-glucosyltransferase EC 2.4.1.82: galactinol—sucrose galactosyltransferase EC 2.4.1.83: dolichyl-phosphate β-D -mannosyltransferase EC 2.4.1.84: deleted, included in EC 2.4.1.17 EC 2.4.1.85: cyanohydrin β-glucosyltransferase EC 2.4.1.86: N-acetyl-β-D-glucosaminide β-(1,3)-galactosyltransferase EC 2.4.1.87: N-acetyllactosaminide 3-α-galactosyltransferase EC 2.4.1.88: globoside α-N-acetylgalactosaminyltransferase EC 2.4.1.89: deleted, included in EC 2.4.1.69, type 1 galactoside α-(1,2)-fucosyltransferase EC 2.4.1.90: N-acetyllactosamine synthase EC 2.4.1.91: flavonol 3-O-glucosyltransferase EC 2.4.1.92: (N-acetylneuraminyl)-galactosylglucosylceramide N-acetylgalactosaminyltransferase EC 2.4.1.93: Now EC 4.2.2.18, inulin fructotransferase (DFA-III-forming) EC 2.4.1.94: protein N-acetylglucosaminyltransferase EC 2.4.1.95: deleted EC 2.4.1.96: sn-glycerol-3-phosphate 1-galactosyltransferase EC 2.4.1.97: 1,3-β-D-glucan phosphorylase EC 2.4.1.98: deleted, Now included with EC 2.4.1.90, N-acetyllactosamine synthase EC 2.4.1.99: sucrose:sucrose fructosyltransferase EC 2.4.1.100: 2,1-fructan:2,1-fructan 1-fructosyltransferase EC 2.4.1.101: α-1,3-mannosyl-glycoprotein 2-β-N-acetylglucosaminyltransferase EC 2.4.1.102: β-1,3-galactosyl-O-glycosyl-glycoprotein β-1,6-N-acetylglucosaminyltransferase EC 2.4.1.103: alizarin 2-β-glucosyltransferase EC 2.4.1.104: o-dihydroxycoumarin 7-O-glucosyltransferase EC 2.4.1.105: vitexin β-glucosyltransferase EC 2.4.1.106: isovitexin β-glucosyltransferase EC 2.4.1.107: deleted, now included with EC 2.4.1.17, glucuronosyltransferase EC 2.4.1.108: deleted, now included with EC 2.4.1.17, glucuronosyltransferase EC 2.4.1.109: dolichyl-phosphate-mannose—protein mannosyltransferase EC 2.4.1.110: tRNA-queuosine β-mannosyltransferase EC 2.4.1.111: coniferyl-alcohol glucosyltransferase EC 2.4.1.112: The protein referred to in this entry is now known to be glycogenin so the entry has been incorporated into EC 2.4.1.186, glycogenin glucosyltransferase EC 2.4.1.113: α-1,4-glucan-protein synthase (ADP-forming) EC 2.4.1.114: 2-coumarate O-β-glucosyltransferase EC 2.4.1.115: anthocyanidin 3-O-glucosyltransferase EC 2.4.1.116: cyanidin 3-O-rutinoside 5-O-glucosyltransferase EC 2.4.1.117: dolichyl-phosphate β-glucosyltransferase EC 2.4.1.118: cytokinin 7-β-glucosyltransferase EC 2.4.1.119: transferred to EC 2.4.99.18, dolichyl-diphosphooligosaccharideprotein glycotransferase EC 2.4.1.120: sinapate 1-glucosyltransferase EC 2.4.1.121: indole-3-acetate β-glucosyltransferase EC 2.4.1.122: N-acetylgalactosaminide β-1,3-galactosyltransferase EC 2.4.1.123: inositol 3-α-galactosyltransferase EC 2.4.1.124: Now EC 2.4.1.87, N-acetyllactosaminide 3-α-galactosyltransferase EC 2.4.1.125: sucrose—1,6-α-glucan 3(6)-α-glucosyltransferase EC 2.4.1.126: hydroxycinnamate 4-β-glucosyltransferase EC 2.4.1.127: monoterpenol β-glucosyltransferase EC 2.4.1.128: scopoletin glucosyltransferase EC 2.4.1.129: peptidoglycan glycosyltransferase EC 2.4.1.130: Now covered by EC 2.4.1.258, EC 2.4.1.259, EC 2.4.1.260 and EC 2.4.1.261 EC 2.4.1.131: GDP-Man:Man3GlcNAc2-PP-dolichol α-1,2-mannosyltransferase EC 2.4.1.132: GDP-Man:Man1GlcNAc2-PP-dolichol α-1,3-mannosyltransferase EC 2.4.1.133: xylosylprotein 4-β-galactosyltransferase EC 2.4.1.134: galactosylxylosylprotein 3-β-galactosyltransferase EC 2.4.1.135: galactosylgalactosylxylosylprotein 3-β-glucuronosyltransferase EC 2.4.1.136: gallate 1-β-glucosyltransferase EC 2.4.1.137: sn-glycerol-3-phosphate 2-α-galactosyltransferase EC 2.4.1.138: mannotetraose 2-α-N-acetylglucosaminyltransferase EC 2.4.1.139: maltose synthase EC 2.4.1.140: alternansucrase EC 2.4.1.141: N-acetylglucosaminyldiphosphodolichol N-acetylglucosaminyltransferase EC 2.4.1.142: chitobiosyldiphosphodolichol β-mannosyltransferase EC 2.4.1.143: α-1,6-mannosyl-glycoprotein 2-β-N-acetylglucosaminyltransferase EC 2.4.1.144: β-1,4-mannosyl-glycoprotein 4-β-N-acetylglucosaminyltransferase EC 2.4.1.145: α-1,3-mannosyl-glycoprotein 4-β-N-acetylglucosaminyltransferase EC 2.4.1.146: β-1,3-galactosyl-O-glycosyl-glycoprotein β-1,3-N-acetylglucosaminyltransferase EC 2.4.1.147: acetylgalactosaminyl-O-glycosyl-glycoprotein β-1,3-N-acetylglucosaminyltransferase EC 2.4.1.148: acetylgalactosaminyl-O-glycosyl-glycoprotein β-1,6-N-acetylglucosaminyltransferase EC 2.4.1.149: N-acetyllactosaminide β-1,3-N-acetylglucosaminyltransferase EC 2.4.1.150: N-acetyllactosaminide β-1,6-N-acetylglucosaminyltransferase EC 2.4.1.151: now included with EC 2.4.1.87 N-acetyllactosaminide 3-α-galactosyltransferase EC 2.4.1.152: 4-galactosyl-N-acetylglucosaminide 3-α-L-fucosyltransferase EC 2.4.1.153: UDP-N-acetylglucosamine—dolichyl-phosphate N-acetylglucosaminyltransferase EC 2.4.1.154: identical to EC 2.4.1.79, globotriaosylceramide 3-β-N-acetylgalactosaminyltransferase EC 2.4.1.155: α-1,6-mannosyl-glycoprotein 6-β-N-acetylglucosaminyltransferase EC 2.4.1.156: indolylacetyl-myo-inositol galactosyltransferase EC 2.4.1.157: 1,2-diacylglycerol 3-glucosyltransferase, now classified as EC 2.4.1.336, monoglucosyldiacylglycerol synthase, and EC 2.4.1.337, 1,2-diacylglycerol 3-α-glucosyltransferase EC 2.4.1.158: 13-hydroxydocosanoate 13-β-glucosyltransferase EC 2.4.1.159: flavonol-3-O-glucoside L-rhamnosyltransferase EC 2.4.1.160: pyridoxine 5′-O-β-D-glucosyltransferase EC 2.4.1.161: oligosaccharide 4-α-D-glucosyltransferase EC 2.4.1.162: aldose β-D-fructosyltransferase EC 2.4.1.163: now included in EC 2.4.1.149, N-acetyllactosaminide β-1,3-N-acetylglucosaminyltransferase EC 2.4.1.164: now included with EC 2.4.1.150, N-acetyllactosaminide β-1,6-N-acetylglucosaminyltransferase EC 2.4.1.165: N-acetylneuraminylgalactosylglucosylceramide β-1,4-N-acetylgalactosaminyltransferase EC 2.4.1.166: raffinose—raffinose α-galactosyltransferase EC 2.4.1.167: sucrose 6F-α-galactosyltransferase EC 2.4.1.168: xyloglucan 4-glucosyltransferase EC 2.4.1.169: now EC 2.4.2.39, xyloglucan 6-xylosyltransferase EC 2.4.1.170: isoflavone 7-O-glucosyltransferase EC 2.4.1.171: methyl-ONN-azoxymethanol β-D-glucosyltransferase EC 2.4.1.172: salicyl-alcohol β-D-glucosyltransferase EC 2.4.1.173: sterol 3β-glucosyltransferase EC 2.4.1.174: glucuronylgalactosylproteoglycan 4-β-N-acetylgalactosaminyltransferase EC 2.4.1.175: glucuronosyl-N-acetylgalactosaminyl-proteoglycan 4-β-N-acetylgalactosaminyltransferase EC 2.4.1.176: gibberellin β-D-glucosyltransferase EC 2.4.1.177: cinnamate β-D-glucosyltransferase EC 2.4.1.178: hydroxymandelonitrile glucosyltransferase EC 2.4.1.179: lactosylceramide β-1,3-galactosyltransferase EC 2.4.1.180: lipopolysaccharide N-acetylmannosaminouronosyltransferase EC 2.4.1.181: hydroxyanthraquinone glucosyltransferase EC 2.4.1.182: lipid-A-disaccharide synthase EC 2.4.1.183: α-1,3-glucan synthase EC 2.4.1.184: galactolipid galactosyltransferase EC 2.4.1.185: flavanone 7-O-β-glucosyltransferase EC 2.4.1.186: glycogenin glucosyltransferase EC 2.4.1.187: N-acetylglucosaminyldiphosphoundecaprenol N-acetyl-β-D-mannosaminyltransferase EC 2.4.1.188: N-acetylglucosaminyldiphosphoundecaprenol glucosyltransferase EC 2.4.1.189: uteolin 7-O-glucuronosyltransferase EC 2.4.1.190: luteolin-7-O-glucuronide 2′′-O-glucuronosyltransferase EC 2.4.1.191: luteolin-7-O-diglucuronide 4′-O-glucuronosyltransferase EC 2.4.1.192: nuatigenin 3β-glucosyltransferase EC 2.4.1.193: sarsapogenin 3β-glucosyltransferase EC 2.4.1.194: 4-hydroxybenzoate 4-O-β-D-glucosyltransferase EC 2.4.1.195: N-hydroxythioamide S-β-glucosyltransferase EC 2.4.1.196: nicotinate glucosyltransferase EC 2.4.1.197: high-mannose-oligosaccharide β-1,4-N-acetylglucosaminyltransferase EC 2.4.1.198: phosphatidylinositol N-acetylglucosaminyltransferase EC 2.4.1.199: β-mannosylphosphodecaprenol—mannooligosaccharide 6-mannosyltransferase EC 2.4.1.200: now EC 4.2.2.17, inulin fructotransferase (DFA-I-forming) EC 2.4.1.201: α-1,6-mannosyl-glycoprotein 4-β-N-acetylglucosaminyltransferase EC 2.4.1.202: 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one 2-D-glucosyltransferase EC 2.4.1.203: trans-zeatin O-β-D-glucosyltransferase EC 2.4.1.204: now EC 2.4.2.40, zeatin O-β-D-xylosyltransferase EC 2.4.1.205: galactogen 6β-galactosyltransferase EC 2.4.1.206: lactosylceramide 1,3-N-acetyl-β-D-glucosaminyltransferase EC 2.4.1.207: xyloglucan:xyloglucosyl transferase EC 2.4.1.208: diglucosyl diacylglycerol synthase (1,2-linking) EC 2.4.1.209: cis-p-coumarate glucosyltransferase EC 2.4.1.210: limonoid glucosyltransferase EC 2.4.1.211: 1,3-β-galactosyl-N-acetylhexosamine phosphorylase EC 2.4.1.212: hyaluronan synthase EC 2.4.1.213: glucosylglycerol-phosphate synthase EC 2.4.1.214: glycoprotein 3-α-L-fucosyltransferase EC 2.4.1.215: cis-zeatin O-β-D-glucosyltransferase EC 2.4.1.216: trehalose 6-phosphate phosphorylase EC 2.4.1.217: mannosyl-3-phosphoglycerate synthase EC 2.4.1.218: hydroquinone glucosyltransferase EC 2.4.1.219: vomilenine glucosyltransferase EC 2.4.1.220: indoxyl-UDPG glucosyltransferase EC 2.4.1.221: peptide-O-fucosyltransferase EC 2.4.1.222: O-fucosylpeptide 3-β-N-acetylglucosaminyltransferase EC 2.4.1.223: glucuronosyl-galactosyl-proteoglycan 4-α-N-acetylglucosaminyltransferase EC 2.4.1.224: glucuronosyl-N-acetylglucosaminyl-proteoglycan 4-α-N-acetylglucosaminyltransferase EC 2.4.1.225: N-acetylglucosaminyl-proteoglycan 4-β-glucuronosyltransferase EC 2.4.1.226: N-acetylgalactosaminyl-proteoglycan 3-β-glucuronosyltransferase EC 2.4.1.227: undecaprenyldiphospho-muramoylpentapeptide β-N-acetylglucosaminyltransferase EC 2.4.1.228: lactosylceramide 4-α-galactosyltransferase EC 2.4.1.229: [Skp1-protein]-hydroxyproline N-acetylglucosaminyltransferase EC 2.4.1.230: kojibiose phosphorylase EC 2.4.1.231: α,α-trehalose phosphorylase (configuration-retaining) EC 2.4.1.232: initiation-specific α-1,6-mannosyltransferase EC 2.4.1.233: deleted: identical to EC 2.4.1.115, anthocyanidin 3-O-glucosyltransferase EC 2.4.1.234: kaempferol 3-O-galactosyltransferase EC 2.4.1.235: deleted: identical to EC 2.4.1.116, cyanidin 3-O-rutinoside 5-O-glucosyltransferase EC 2.4.1.236: flavanone 7-O-glucoside 2′′-O-β-L-rhamnosyltransferase EC 2.4.1.237: flavonol 7-O-β-glucosyltransferase EC 2.4.1.238: delphinidin 3,5-di-O-glucoside 3′-O-glucosyltransferase EC 2.4.1.239: flavonol-3-O-glucoside glucosyltransferase EC 2.4.1.240: flavonol-3-O-glycoside glucosyltransferase EC 2.4.1.241: flavonol-3-O-glycoside glucosyltransferase EC 2.4.1.242: NDP-glucose—starch glucosyltransferase EC 2.4.1.243: 6G-fructosyltransferase EC 2.4.1.244: N-acetyl-β-glucosaminyl-glycoprotein 4-β-N-acetylgalactosaminyltransferase EC 2.4.1.245: α,α-trehalose synthase EC 2.4.1.246: mannosylfructose-phosphate synthase EC 2.4.1.247: β-D-galactosyl-(1→4)-L-rhamnose phosphorylase EC 2.4.1.248: cycloisomaltooligosaccharide glucanotransferase EC 2.4.1.249: delphinidin 3′,5′-O-glucosyltransferase EC 2.4.1.250: D-inositol-3-phosphate glycosyltransferase EC 2.4.1.251: GlcA-β-(1→2)-D-Man-α-(1→3)-D-Glc-β-(1→4)-D-Glc-α-1-diphospho-ditrans,octacis-undecaprenol 4-β-mannosyltransferase EC 2.4.1.252: GDP-mannose:cellobiosyl-diphosphopolyprenol α-mannosyltransferase EC 2.4.1.253: baicalein 7-O-glucuronosyltransferase EC 2.4.1.254: cyanidin-3-O-glucoside 2′′-O-glucuronosyltransferase EC 2.4.1.255: protein O-GlcNAc transferase EC 2.4.1.256: dolichyl-P-Glc:Glc2Man9GlcNAc2-PP-dolichol α-1,2-glucosyltransferase EC 2.4.1.257: GDP-Man:Man2GlcNAc2-PP-dolichol α-1,6-mannosyltransferase EC 2.4.1.258: dolichyl-P-Man:Man5GlcNAc2-PP-dolichol α-1,3-mannosyltransferase EC 2.4.1.259: dolichyl-P-Man:Man6GlcNAc2-PP-dolichol α-1,2-mannosyltransferase EC 2.4.1.260: dolichyl-P-Man:Man7GlcNAc2-PP-dolichol α-1,6-mannosyltransferase EC 2.4.1.261: dolichyl-P-Man:Man8GlcNAc2-PP-dolichol α-1,2-mannosyltransferase EC 2.4.1.262: soyasapogenol glucuronosyltransferase EC 2.4.1.263: abscisate β-glucosyltransferase EC 2.4.1.264: D-Man-α-(1→3)-D-Glc-β-(1→4)-DD-Glc-α-1-diphosphoundecaprenol 2-β-glucuronosyltransferase EC 2.4.1.265: olichyl-P-Glc:Glc1Man9GlcNAc2-PP-dolichol α-1,3-glucosyltransferase EC 2.4.1.266: glucosyl-3-phosphoglycerate synthase EC 2.4.1.267: dolichyl-P-Glc:Man9GlcNAc2-PP-dolichol α-1,3-glucosyltransferase EC 2.4.1.268: glucosylglycerate synthase EC 2.4.1.269: mannosylglycerate synthase EC 2.4.1.270: mannosylglucosyl-3-phosphoglycerate synthase EC 2.4.1.271: crocetin glucosyltransferase EC 2.4.1.272: soyasapogenol B glucuronide galactosyltransferase EC 2.4.1.273: soyasaponin III rhamnosyltransferase EC 2.4.1.274: glucosylceramide β-1,4-galactosyltransferase EC 2.4.1.275: neolactotriaosylceramide β-1,4-galactosyltransferase EC 2.4.1.276: zeaxanthin glucosyltransferase EC 2.4.1.277: glycosyltransferase DesVII EC 2.4.1.278: desosaminyl transferase EryCIII EC 2.4.1.279: nigerose phosphorylase EC 2.4.1.280: N,N′-diacetylchitobiose phosphorylase EC 2.4.1.281: 4-O-β-D-mannosyl-D-glucose phosphorylase EC 2.4.1.282: 3-O-α-D-glucosyl-L-rhamnose phosphorylase EC 2.4.1.283: 2-deoxystreptamine N-acetyl-D-glucosaminyltransferase EC 2.4.1.284: 2-deoxystreptamine glucosyltransferase EC 2.4.1.285: UDP-GlcNAc:ribostamycin N-acetylglucosaminyltransferase EC 2.4.1.286: chalcone 4′-O-glucosyltransferase EC 2.4.1.287: rhamnopyranosyl-N-acetylglucosaminyl-diphospho-decaprenol β-1,4/1,5-galactofuranosyltransferase EC 2.4.1.288: galactofuranosylgalactofuranosylrhamnosyl-N-acetylglucosaminyl-diphospho-decaprenol β-1,5/1,6-galactofuranosyltransferase EC 2.4.1.289: N-acetylglucosaminyl-diphospho-decaprenol L-rhamnosyltransferase EC 2.4.1.290: N,N′-diacetylbacillosaminyl-diphospho-undecaprenol α-1,3-N-acetylgalactosaminyltransferase EC 2.4.1.291: N-acetylgalactosamine-N,N′-diacetylbacillosaminyl-diphospho-undecaprenol 4-α-N-acetylgalactosaminyltransferase EC 2.4.1.292: GalNAc-α-(1→4)-GalNAc-α-(1→3)-diNAcBac-PP-undecaprenol α-1,4-N-acetyl-D-galactosaminyltransferase EC 2.4.1.293: GalNAc5-diNAcBac-PP-undecaprenol β-1,3-glucosyltransferase EC 2.4.1.294: cyanidin 3-O-galactosyltransferase EC 2.4.1.295: anthocyanin 3-O-sambubioside 5-O-glucosyltransferase EC 2.4.1.296: anthocyanidin 3-O-coumaroylrutinoside 5-O-glucosyltransferase EC 2.4.1.297: anthocyanidin 3-O-glucoside 2′′-O-glucosyltransferase EC 2.4.1.298: anthocyanidin 3-O-glucoside 5-O-glucosyltransferase EC 2.4.1.299: cyanidin 3-O-glucoside 5-O-glucosyltransferase (acyl-glucose) EC 2.4.1.300: cyanidin 3-O-glucoside 7-O-glucosyltransferase (acyl-glucose) EC 2.4.1.301: 2′-deamino-2′-hydroxyneamine 1-α-D-kanosaminyltransferase EC 2.4.1.302: L-demethylnoviosyl transferase EC 2.4.1.303: UDP-Gal:α-D-GlcNAc-diphosphoundecaprenol β-1,3-galactosyltransferase EC 2.4.1.304: UDP-Gal:α-D-GlcNAc-diphosphoundecaprenol β-1,4-galactosyltransferase EC 2.4.1.305: UDP-Glc:α-D-GlcNAc-glucosaminyl-diphosphoundecaprenol β-1,3-glucosyltransferase EC 2.4.1.306: UDP-GalNAc:α-D-GalNAc-diphosphoundecaprenol α-1,3-N-acetylgalactosaminyltransferase EC 2.4.1.307: UDP-Gal:α-D-GalNAc-1,3-α-D-GalNAc-diphosphoundecaprenol β-1,3-galactosyltransferase. Now included in EC 2.4.1.122, N-acetylgalactosaminide β-1,3-galactosyltransferase EC 2.4.1.308: GDP-Fuc:β-D-Gal-1,3-α-D-GalNAc-1,3-α-GalNAc-diphosphoundecaprenol α-1,2-fucosyltransferase EC 2.4.1.309: UDP-Gal:α-L-Fuc-1,2-β-Gal-1,3-α-GalNAc-1,3-α-GalNAc-diphosphoundecaprenol α-1,3-galactosyltransferase EC 2.4.1.310: vancomycin aglycone glucosyltransferase EC 2.4.1.311: chloroorienticin B synthase EC 2.4.1.312: protein O-mannose β-1,4-N-acetylglucosaminyltransferase EC 2.4.1.313: protein O-mannose β-1,3-N-acetylgalactosaminyltransferase EC 2.4.1.314: ginsenoside Rd glucosyltransferase EC 2.4.1.315: diglucosyl diacylglycerol synthase (1,6-linking) EC 2.4.1.316: tylactone mycaminosyltransferase EC 2.4.1.317: O-mycaminosyltylonolide 6-deoxyallosyltransferase EC 2.4.1.318: demethyllactenocin mycarosyltransferase EC 2.4.1.319: β-1,4-mannooligosaccharide phosphorylase EC 2.4.1.320: 1,4-β-mannosyl-N-acetylglucosamine phosphorylase EC 2.4.1.321: cellobionic acid phosphorylase EC 2.4.1.322: devancosaminyl-vancomycin vancosaminetransferase EC 2.4.1.323: 7-deoxyloganetic acid glucosyltransferase EC 2.4.1.324: 7-deoxyloganetin glucosyltransferase EC 2.4.1.325: TDP-N-acetylfucosamine:lipid II N-acetylfucosaminyltransferase EC 2.4.1.326: aklavinone 7-L-rhodosaminyltransferase EC 2.4.1.327: aclacinomycin-T 2-deoxy-L-fucose transferase EC 2.4.1.328: erythronolide mycarosyltransferase EC 2.4.1.329: sucrose 6F-phosphate phosphorylase EC 2.4.1.330: β-D-glucosyl crocetin β-1,6-glucosyltransferase EC 2.4.1.331: 8-demethyltetracenomycin C L-rhamnosyltransferase EC 2.4.1.332: 1,2-α-glucosylglycerol phosphorylase EC 2.4.1.333: 1,2-β-oligoglucan phosphorylase EC 2.4.1.334: 1,3-α-oligoglucan phosphorylase EC 2.4.1.335: dolichyl N-acetyl-α-D-glucosaminyl phosphate 3-β-D-2,3-diacetamido-2,3-dideoxy-β-D-glucuronosyltransferase EC 2.4.1.336: monoglucosyldiacylglycerol synthase EC 2.4.1.337: 1,2-diacylglycerol 3-α-glucosyltransferase EC 2.4.1.338: validoxylamine A glucosyltransferase EC 2.4.1.339: β-1,2-mannobiose phosphorylase EC 2.4.1.340: 1,2-β-oligomannan phosphorylase EC 2.4.1.341: α-1,2-colitosyltransferase EC 2.4.1.342: α-maltose-1-phosphate synthase EC 2.4.1.343: UDP-Gal:α-D-GlcNAc-diphosphoundecaprenol α-1,3-galactosyltransferase EC 2.4.1.344: type 2 galactoside α-(1,2)-fucosyltransferase EC 2.4.1.345: phosphatidyl-myo-inositol α-mannosyltransferase EC 2.4.1.346: phosphatidyl-myo-inositol dimannoside synthase EC 2.4.1.347: α,α-trehalose-phosphate synthase (ADP-forming) EC 2.4.1.348: N-acetyl-α-D-glucosaminyl-diphospho-ditrans,octacis-undecaprenol 3-α-mannosyltransferase EC 2.4.1.349: mannosyl-N-acetyl-α-D-glucosaminyl-diphospho-ditrans,octacis-undecaprenol 3-α-mannosyltransferase EC 2.4.1.350: mogroside IE synthase EC 2.4.1.351: rhamnogalacturonan I rhamnosyltransferase EC 2.4.1.352: glucosylglycerate phosphorylase EC 2.4.1.353: sordaricin 6-deoxyaltrosyltransferase EC 2.4.1.354: (R)-mandelonitrile β-glucosyltransferase EC 2.4.1.355: poly(ribitol-phosphate) β-N-acetylglucosaminyltransferase EC 2.4.1.356: glucosyl-dolichyl phosphate glucuronosyltransferase EC 2.4.1.357: phlorizin synthase EC 2.4.1.358: acylphloroglucinol glucosyltransferase EC 2.4.1.359: glucosylglycerol phosphorylase (configuration-retaining) EC 2.4.1.360: 2-hydroxyflavanone C-glucosyltransferase EC 2.4.1.361: GDP-mannose:di-myo-inositol-1,3′-phosphate β-1,2-mannosyltransferase EC 2.4.1.362: α-(1→3) branching sucrase EC 2.4.1.363: ginsenoside 20-O-glucosyltransferase EC 2.4.1.364: protopanaxadiol-type ginsenoside 3-O-glucosyltransferase EC 2.4.1.365: protopanaxadiol-type ginsenoside-3-O-glucoside 2′′-O-glucosyltransferase EC 2.4.1.366: ginsenoside F1 6-O-glucosyltransferase EC 2.4.1.367: ginsenoside 6-O-glucosyltransferase EC 2.4.1.368: oleanolate 3-O-glucosyltransferase EC 2.4.1.369: enterobactin C-glucosyltransferase EC 2.4.1.370: inositol phosphorylceramide mannosyltransferase EC 2.4.1.371: polymannosyl GlcNAc-diphospho-ditrans,octacis-undecaprenol 2,3-α-mannosylpolymerase EC 2.4.1.372: mutansucrase EC 2.4.1.373: α-(1→2) branching sucrase EC 2.4.1.374: β-1,2-mannooligosaccharide synthase EC 2.4.1.375: rhamnogalacturonan I galactosyltransferase EC 2.4.1.376: EGF-domain serine glucosyltransferase EC 2.4.1.377: dTDP-Rha:α-D-Gal-diphosphoundecaprenol α-1,3-rhamnosyltransferase EC 2.4.1.378: GDP-mannose:α-L-Rha-(1→3)-α-D-Gal-PP-Und α-1,4-mannosyltransferase EC 2.4.1.379: GDP-Man:α-D-Gal-diphosphoundecaprenol α-1,3-mannosyltransferase EC 2.4.1.380: GDP-Man:α-D-Man-(1→3)-α-D-Gal diphosphoundecaprenol α-1,2-mannosyltransferase EC 2.4.1.381: dTDP-Rha:α-D-Man-(1→3)-α-D-Gal diphosphoundecaprenol α-1,2-rhamnosyltransferase EC 2.4.1.382: CDP-abequose:α-L-Rha2OAc-(1→2)-α-D-Man-(1→2)-α-D-Man-(1→3)-α-D-Gal-PP-Und α-1,3-abequosyltransferase EC 2.4.1.383: GDP-Man:α-L-Rha-(1→3)-α-D-Gal-PP-Und β-1,4-mannosyltransferase EC 2.4.1.384: NDP-glycosyltransferase

== Cap snatching in Arenaviridae and Bunyavirales == The family Arenaviridae and order Bunyavirales are also segmented negative, single-stranded RNA viruses. A verified Mn2+ dependent endonuclease is located at the N-terminus of the L protein. TN-terminal domain is conserved between various families, suggesting evolutionary similarity. However, the cap-binding domain is not confirmed for every virus family, but it is believed to be located in the L or nucleocapsid (N or NP) protein.[1] In the bunyavirales, endonuclease cleavage and nucleotide motif preferences vary between families, genera and species. This variation occurs because of a need to some base pairing with the 3' end of the viral genome. The nucleoprotein structure in Lassa virus (Arenaviridae) contains a second nuclease. Researchers propose that it is involved in attenuating interferon response, but it also contains a dTTP-binding site which may be used for cap-snatching. In this model, the L and N proteins cooperate in the cap-snatching process. The two-domain model has also been prosed for hantaviruses, but the N protein in the rift valley fever virus (Phenuiviridae) does not possess the same features.

The Chinese red-headed centipede, also known as the Chinese red head, (Scolopendra mutilans) is a centipede from East Asia (type locality: Japan). It averages 20 cm (8 in) in length and lives in damp environments.

=== Marketing ethics issue === Although a "functional" beverage may be marketed as a panacea or a performance-enhancing substance, there is no scientific evidence for any specific health effects of such beverages or for their uniform regulation internationally, as of 2020.

The reinforced labour faction of the party initially accorded a more left-wing orientation and facilitated the cooperation with the social democrats. Typically, the Zentrum defended anti-capitalist policies and promoted social policy, but never agreed with social democrats on the right to private property. By the late Twenties, however, the Center Party gradually returned to more conservative policies.

Sources: en.wikipedia.org

Supporting material

Flavins in general have fluorescent activity when unbound (proteins bound to flavin nucleic acid derivatives are called flavoproteins). This property can be utilized when examining protein binding, observing loss of fluorescent activity when put into the bound state. Oxidized flavins have high absorbances of about 450 nm, and fluoresce at about 515-520 nm.

=== RNA polymerase II === Proline isomerization of certain prolines in RNA polymerase II is key in the process of recruiting and placing processing factors during transcription. PPIases target RNA polymerase II by interacting with the Rpb1 carboxy terminal domain, or CTD. Proline isomerization is then used as part of the mechanism of the CTD to recruit co-factors required for co-transcriptional RNA processing, regulating RNA polymerase II activity. Nrd1 is a protein that is responsible for many of the transcriptional activities of RNAP II, specifically through the Nrd1- dependent termination pathway. This pathway requires the parvulin Ess1, or Pin1 depending on the organism, to isomerize the pSer5-Pro6 bond in the CTD. Without the cis conformation of the pSer5-Pro6 bond, created by Ess1/Pin1, Nrd1 cannot bind to RNAP II. Any variation from this process leads to a decrease in Nrd1 binding affinity, lowering the ability of RNAP II to process and degrade noncoding RNAs.

Around 2009, Japanese military strategist Toshi Yoshihara and Naval War College professor James R. Holmes suggested the American military could exploit the geography of the first island chain to counter the People's Liberation Army Navy build-up. The Cabinet of Japan has also passed defense white papers emphasizing the threat posed by the People's Liberation Army Navy in the first island chain. In the later years of the 2010s, Japan started deploying military assets to Yonaguni and its other islands to counter China's presence along that area of the first island chain. Japan's strategic position in the first island chain began with US-Japan joint efforts to counter Soviet expansion. The Japan Self-Defense Forces currently plays the role of protecting US military bases and preserving military strength in East Asia. As for Japan's Territorial Protection Self-Defense Forces, which mainly rely on islands in southern Japan adjacent to the Yellow Sea and the East China Sea, Japan has military advantages in anti-submarine, air defense and sea mine technologies. In 2026, Japan and the US agreed to expand joint military training across the first island chain.

== Overshoot Day == The Global Footprint Network measures the ecological footprint of the world's nations versus each nation's biocapacity. From this it derives an Earth Overshoot Day, an aggregation of the "overshoot day" for each country. The overshoot day is the day that the nation's footprint exceeds its biocapacity. Measurements are made in global hectares (gha). In 2019, the group issued their analysis based on 2016 data. Overshoot days for 135 countries ranged from Qatar on 11 February to Kyrgyzstan on 26 December. Thailand's overshoot day is 28 August. Overshoot days for other ASEAN nations were: Singapore, 12 April; Brunei, 21 May; Malaysia, 1 June; Vietnam, 8 October; Laos, 9 November; Indonesia, 18 December; Myanmar, 25 December. The ecological footprint per person in Cambodia and the Philippines are less than global biocapacity constant (1.63 gha) and thus do not have an overshoot day.

=== Parasites === Emus can suffer from both external and internal parasites, but under farmed conditions are more parasite-free than ostriches or rheas. External parasites include the louse Dahlemhornia asymmetrica and various other lice, ticks, mites and flies. Chicks sometimes suffer from intestinal tract infections caused by coccidian protozoa, and the nematode Trichostrongylus tenuis infects the emu as well as a wide range of other birds, causing haemorrhagic diarrhoea. Other nematodes are found in the trachea and bronchi; Syngamus trachea causing haemorrhagic tracheitis and Cyathostoma variegatum causing serious respiratory problems in juveniles.

Sources: en.wikipedia.org

Frequently asked questions

Is TB-500 the same as thymosin beta-4?

Not necessarily. TB-500 is a commercial label that suppliers apply to synthetic peptides described as thymosin beta-4 or a fragment of it. Published research most often studies the full-length protein, so statements about one do not automatically transfer to the other.

Has any regulator approved TB-500 for medical use?

No. No major regulatory authority lists an approved product under this name, and no pharmacopoeial monograph exists for it. Material sold under the label is therefore supplied outside approved pharmaceutical channels, which affects the quality documentation available.

Why does TB-500 appear in anti-doping literature?

It falls within a prohibited class covering peptide hormones and growth factors, based on presumed effects on tissue repair and blood vessel formation. Anti-doping laboratories have published mass spectrometry methods for detecting thymosin beta-4 related peptides in urine samples.

What is TB-500?

TB-500 is a trade-style label for a synthetic peptide connected to thymosin beta-4. It is sold mainly through research-chemical channels and is not a single chemically defined product across suppliers.

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