{"id":1814,"date":"2026-06-05T22:40:14","date_gmt":"2026-06-05T22:40:14","guid":{"rendered":"https:\/\/one-peptides.com\/?post_type=product&p=1814"},"modified":"2026-09-29T16:59:30","modified_gmt":"2026-09-29T16:59:30","slug":"tb-500-20-mg-pen","status":"publish","type":"product","link":"https:\/\/one-peptides.com\/es\/producto\/tb-500-20-mg-pen\/","title":{"rendered":"TB-500 20 mg PEN"},"content":{"rendered":"

One-Peptides TB-500 20 mg PEN – Thymosin Beta-4 fragment in a pre-dissolved pen<\/h2>\n

TB-500 20 mg PEN is a <\/span>research reagent (Research Use Only)<\/strong> in the form of a pre-dissolved pen. The pen is the physical format of the reagent; <\/span>TB-500 is not a registered medicine in any jurisdiction<\/strong>. Label: “For research use only. Not for human use”. <\/span>TB-500 (Thymosin Beta-4) is listed on the WADA Prohibited List year-round (S2)<\/strong> – athletes subject to anti-doping control must not use TB-500 at any time.<\/span><\/em><\/p>\n

In the literature on regenerative peptides, the Thymosin Beta-4 fragment occupies a special place. Full-length Tbeta4 was isolated from calf thymus in 1981 by Allan Goldstein and Ewald Hannappel; since then, it has remained one of the best-described regulators of the actin cytoskeleton in cell biology. TB-500 in RUO reagent trade<\/strong> typically refers to the synthetic heptapeptide LKKTETQ<\/strong> (positions 17-23 of full Tbeta4), containing the actin-binding motif responsible for G-actin sequestration. Some suppliers also use the name “TB-500” for full-length Thymosin Beta-4 (43 amino acids); a professional supplier clearly states the sequence in the COA. A full literature overview is available in the article on tissue repair and Thymosin Beta-4<\/a>.<\/p>\n

The pre-dissolved pen format containing 20 mg of peptide<\/strong> is an operational solution for laboratories that want to skip the lyophilizate reconstitution step. The pen contains a solution ready for microliter sampling: no bacteriostatic water measurement, no solvent-error risk, and one batch number for the entire material. The broader mechanistic background of regenerative peptides is discussed in the guide to regenerative peptides<\/a>.<\/p>\n

What is TB-500 20 mg PEN – sequence and class<\/h2>\n

In a research reagent catalogue, TB-500 refers to a synthetic N-terminal fragment of Thymosin Beta-4 (Tbeta4)<\/strong> with the sequence Leu-Lys-Lys-Thr-Glu-Thr-Gln (LKKTETQ)<\/strong> – positions 17-23 of the full protein and the biochemical core of Tbeta4 activity. Full-length Thymosin Beta-4 is a 43-amino-acid cytoplasmic protein of approximately 4961 Da from the beta-thymosin<\/strong> class, naturally present in humans with the highest expression in platelets, macrophages and lymphocytes.<\/p>\n

In commerce, the name “TB-500” is used in two ways: most often for the LKKTETQ fragment, while some manufacturers use the label for full-length Tbeta4. The sequence stated in the COA is the only binding reference point<\/strong>; MS mass identification (approximately 880 Da for the fragment vs approximately 4961 Da for full Tbeta4) confirms the structural identity of the batch.<\/p>\n

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Chemical characteristics of TB-500 20 mg PEN<\/h2>\n\n\n\n<\/colgroup>\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Parameter<\/strong><\/th>\nValue<\/strong><\/th>\n<\/tr>\n
Sequence<\/td>\nLKKTETQ (fragment) or full Tbeta4 – specified in the batch COA<\/td>\n<\/tr>\n
Number of amino acids<\/td>\n7 (fragment) or 43 (full Tbeta4)<\/td>\n<\/tr>\n
Molecular mass<\/td>\n~880 Da (fragment) or ~4961 Da (full Tbeta4)<\/td>\n<\/tr>\n
Biochemical class<\/td>\nBeta-thymosin; regulator of the actin cytoskeleton<\/td>\n<\/tr>\n
Historical origin<\/td>\nTbeta4 isolated from calf thymus (Goldstein and Hannappel, 1981)<\/td>\n<\/tr>\n
Biological function<\/td>\nSequestration of monomeric G-actin, modulation of cytoskeletal dynamics<\/td>\n<\/tr>\n
Physical form<\/td>\nPre-dissolved solution in a pen<\/td>\n<\/tr>\n
Peptide mass in pen<\/td>\n20 mg<\/td>\n<\/tr>\n
HPLC purity<\/td>\n>=98%<\/td>\n<\/tr>\n
Identification<\/td>\nMS confirmation (~880 Da for the fragment or ~4961 Da for full Tbeta4)<\/td>\n<\/tr>\n
Salt form<\/td>\nAcetate or TFA salt – specified in the COA<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Mechanism of action in research<\/h2>\n

All reported effects of Tbeta4 and the LKKTETQ fragment originate from one biochemical mechanism<\/strong>: sequestration of monomeric G-actin in a 1:1 ratio, which regulates actin availability for polymerization into F-actin. This single mechanism gives rise to a cascade of secondary effects.<\/p>\n