TB-500 (Thymosin B-4)

About This Research Material

This listing supplies TB-500, the acetate salt of Thymosin Beta-4, as a lyophilized research peptide for in-vitro and preclinical laboratory work only. Thymosin Beta-4 (often abbreviated Tβ4) is a 43-residue, water-soluble peptide belonging to the beta-thymosin family and is one of the most abundant members of that family in the research literature. In laboratory shorthand the material is frequently referred to by the code TB-500, a designation historically used for synthetic beta-thymosin preparations studied in animal and cell-culture models. The compound carries CAS number 77591-33-4 and the molecular formula C212H350N56O78S, corresponding to a single sulfur-bearing methionine within an otherwise acidic, unstructured chain.

The defining structural motif of this peptide in the research literature is its actin-binding sequence. Beta-thymosins contain a short conserved segment (commonly written as the LKKTET-type motif) that mediates interaction with monomeric G-actin. Much of the mechanistic interest in TB-500 as a reference material stems from this actin-sequestering behavior, which places it among the tool compounds used to study cytoskeletal dynamics at the bench. The material is offered strictly as a characterized reference substance for that kind of controlled investigation and has no established consumer application.

What Has Been Studied in Preclinical Models

Published work on Thymosin Beta-4 is predominantly in-vitro and rodent-model in nature and is best understood as mechanistic and hypothesis-generating rather than settled. The summaries below describe observations reported in laboratory systems only; they are not evidence of outcomes in humans or animals, and the research remains preliminary and ongoing.

• Actin-sequestration biochemistry: cell-free and cell-culture assays characterizing how the peptide binds and buffers pools of monomeric G-actin, a role that makes it a recurring probe in cytoskeletal-dynamics research.
• Cell-migration and scratch-wound assays: in-vitro systems used to examine endothelial and fibroblast migration and closure dynamics in cultured monolayers.
• Angiogenesis-associated endpoints: preclinical model systems in which beta-thymosins are used to probe vascular and tissue-remodeling signaling pathways.
• Comparative fragment studies: laboratory work contrasting the full-length peptide with shorter actin-binding fragments to map which residues drive the observed cytoskeletal interactions.

Analytical Characterization

For a 43-residue peptide, reproducible research depends on confirming both sequence fidelity and purity before the material enters an experiment. Each research lot is supplied as a lyophilized powder and characterized using orthogonal methods so that identity (confirmation the molecule is the correct sequence) is separated from purity (how much of the sample is the target peptide). Reversed-phase HPLC (RP-HPLC) quantifies chromatographic purity by peak-area integration, with lot purity reported on the Certificate of Analysis (COA) at ≥98%. The chromatogram resolves the main peak from process-related impurities and truncated sequences that can arise during synthesis of a chain this length.

Identity is confirmed by mass spectrometry (commonly ESI-MS or MALDI-TOF), which verifies that the observed mass matches the theoretical value for the C212H350N56O78S composition rather than a deletion or oxidation variant; the single methionine residue means oxidation state is one attribute worth confirming on the analytical record. Because TB-500 is supplied as an acetate salt, a lyophilized vial also contains counter-ion and residual water, so net peptide content can differ from gross fill weight. Researchers evaluating the material typically review the lot-matched COA for reported HPLC purity, the mass-spec identity confirmation, and net peptide content, and retain it alongside experimental records to support traceability and accurate stock-concentration calculations.

Laboratory Handling of the Lyophilized Peptide

The following describes conventional handling of lyophilized research peptides and is not instruction for human or animal use. As a freeze-dried peptide, TB-500 is hygroscopic and sensitive to repeated temperature cycling. Standard laboratory practice is to allow sealed vials to equilibrate to room temperature before opening to minimize condensation on the powder, and to reconstitute with an appropriate research-grade solvent under aseptic technique. Aliquoting reconstituted stock into single-use portions limits freeze-thaw cycles that can degrade a long, unstructured peptide. Detailed temperature and stability windows for lyophilized, reconstituted, and working solutions appear in the storage table on this page, and handling should follow institutional chemical-safety procedures with appropriate PPE.