TB-500: Research Overview

Full name

Acetyl-(L-seryl-L-aspartyl-L-lysyl-L-prolyl-L-aspartyl-L-methionyl-L-alanyl-L-glutamyl-L-isoleucyl-L-glutamyl-L-lysyl-L-phenylalanyl-L-aspartyl-L-lysyl-L-seryl-L-lysyl-L-leucyl-L-lysyl-L-lysyl-L-threonyl-L-glutamyl-L-threonyl-L-glutamine)

Molecular formula

C212H350N56O78S

Molecular weight

4963.46 g/mol

Sequence / class

Synthetic 23-residue acetylated fragment corresponding to the actin-binding active region of Thymosin Beta-4 (Ac-SDKPDMAEIEKFDKSKLKKTETQ)

Receptor targets

Direct actin sequestration via the actin-binding box motif; published in vitro literature also describes interactions with extracellular matrix proteins and cytoskeletal regulatory cascades

Research classification

Actin-binding cytoskeletal signaling research peptide fragment

PubChem CID

16130571

TB-500 is a synthetic acetylated 23-residue peptide fragment that corresponds to the actin-binding active region of Thymosin Beta-4. The sequence (Ac-SDKPDMAEIEKFDKSKLKKTETQ) reproduces the central LKKTETQ actin-binding box of the full-length parent protein along with adjacent residues that contribute to the structural context of actin engagement. The molecular formula is C212H350N56O78S with a single methionine residue that requires standard precautions against oxidative degradation during handling.

Published literature classifies TB-500 as a cytoskeletal signaling research reagent. The peptide is studied in vitro primarily as an analytical probe for the biochemistry of G-actin sequestration, the dynamics of actin polymerization, and the broader regulatory layer that controls cytoskeletal remodeling in cellular models. Receptor-binding studies indicate that TB-500 does not engage a single classical G-protein-coupled receptor; instead, the published literature describes direct binding to monomeric actin and pathway-level effects on actin-dependent cellular processes.

Research published in cellular biology journals has used TB-500 as a comparator compound for the full-length Thymosin Beta-4 protein. The shorter fragment retains the core actin-binding sequence while being more accessible to solid-phase synthesis at analytical scale, making it useful as a reproducible reagent in in vitro studies of cytoskeletal signaling biochemistry.

Additional published in vitro literature describes the use of TB-500 in studies of angiogenic signaling, endothelial cell migration biochemistry, and extracellular matrix interactions. These reports frame the peptide as a multi-pathway analytical probe rather than a single-target ligand, with the breadth of in vitro effects reflecting the central role of actin biochemistry across cellular research contexts.

Structure reference: Public domain chemical databases (PubChem CID 16130571).

Published in vitro literature has examined TB-500 in cellular models that include endothelial cell migration assays, cardiomyocyte cytoskeletal studies, and fibroblast-based wound-closure scratch assays used as reproducible in vitro readouts of cellular motility biochemistry. Investigators have used the peptide as an analytical probe for studying how short actin-binding sequences alter the kinetics of cytoskeletal remodeling under defined buffer conditions.

Receptor-binding studies indicate that TB-500 sequesters monomeric G-actin directly through the LKKTETQ actin-binding box, with downstream effects on the equilibrium between monomeric and filamentous actin in cellular preparations. Biochemical fractionation, fluorescence microscopy of labeled actin, and live-cell imaging have all appeared as published readouts in this in vitro literature.

Comparative panels that include both TB-500 and the full-length Thymosin Beta-4 parent protein provide useful mechanistic context, allowing investigators to isolate the contribution of the central actin-binding sequence from contributions of flanking regions in the parent protein under matched cellular assay conditions.

• [1]A study published in FASEB Journal (2006) examined Thymosin Beta-4 fragment biochemistry in cellular signaling research and cytoskeletal remodeling models.
• [2]A study published in Annals of the New York Academy of Sciences (2010) reviewed publicly available in vitro literature on Thymosin Beta-4 and synthetic active-fragment analytical reagents.
• [3]A study published in Cell Motility and the Cytoskeleton (2003) investigated actin-binding kinetics of short peptide fragments derived from Thymosin Beta-4 in cellular models.

The above represents a non-exhaustive summary of publicly available research. PūrTONIX does not endorse, validate, or make claims based on any referenced study.

Published chemical property data indicate that TB-500 is soluble in water and in standard aqueous assay buffers at the concentrations typical of in vitro research. The lyophilized peptide is stored at -20°C under inert atmosphere, with attention to the single methionine residue, which is susceptible to oxidation under uncontrolled storage conditions. Inert-atmosphere headspace and minimization of freeze-thaw cycles are standard practice for analytical-grade lots.

Reconstitution in bacteriostatic water or in assay-matched buffer is standard for in vitro cytoskeletal signaling assays. Analytical characterization commonly includes reverse-phase HPLC purity analysis, electrospray mass spectrometry confirming the acetylated 23-residue sequence, and residual solvent screening per ICH Q3C.

Handling recommendations are based on published chemical property data and are intended for qualified laboratory personnel only.

Cytoskeletal signaling assays are sensitive to deletion peptides and to oxidation of the internal methionine residue. Material characterized for high chromatographic purity with documented mass-spectral identity and intact methionine signal provide the analytical baseline required for reproducible in vitro results.