Fequesetide
[CAS# 476014-70-7]

Identification

• Classification: Biochemical >> Peptide
• Name: Fequesetide
• Synonyms: (2S)-5-amino-2-[[(2S,3R)-2-[[(2S)-2-[[(2S,3R)-2-[[(2S)-6-amino-2-[[(2S)-6-amino-2-[[(2S)-2-amino-4-methylpentanoyl]amino]hexanoyl]amino]hexanoyl]amino]-3-hydroxybutanoyl]amino]-4-carboxybutanoyl]amino]-3-hydroxybutanoyl]amino]-5-oxopentanoic acid
• Protein Sequence: LKKTETQ
• Molecular Formula: C₃₆H₆₆N₁₀O₁₃
• Molecular Weight: 846.97
• CAS Registry Number: 476014-70-7
• SMILES: C[C@H]([C@@H](C(=O)N[C@@H](CCC(=O)O)C(=O)N[C@@H]([C@@H](C)O)C(=O)N[C@@H](CCC(=O)N)C(=O)O)NC(=O)[C@H](CCCCN)NC(=O)[C@H](CCCCN)NC(=O)[C@H](CC(C)C)N)O

Properties

• Density: 1.3±0.1 g/cm³ Calc.^*
• Boiling point: 1343.0±65.0 ºC 760 mmHg (Calc.)^*
• Flash point: 766.0±34.3 ºC (Calc.)^*
• Index of refraction: 1.553 (Calc.)^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Discovory and Applicatios

Fequesetide is a short synthetic peptide that has been identified and catalogued as a discrete chemical substance for research use. It is defined by a specific amino acid sequence and corresponds to a fragment derived from larger endogenous peptides associated with actin regulation in eukaryotic cells. The compound is not a naturally occurring small molecule but a laboratory-prepared peptide that represents a functional segment of a protein domain that has been studied for its biological relevance.

The scientific background of Fequesetide is closely connected to research on thymosin family peptides, particularly thymosin beta proteins, which were first isolated and characterized in the second half of the twentieth century during investigations into thymic extracts and their effects on immune and cellular functions. Subsequent biochemical and structural studies demonstrated that thymosin beta peptides play a central role in binding monomeric actin and regulating actin polymerization. As protein chemistry advanced, researchers began to dissect these larger peptides into shorter fragments in order to identify minimal sequences responsible for specific biological activities. Fequesetide emerged from this line of investigation as a defined peptide fragment corresponding to an actin-binding region within thymosin beta proteins.

The discovery of Fequesetide as a distinct research compound did not occur through isolation from natural sources, but rather through rational design and peptide synthesis based on known protein sequences. Solid-phase peptide synthesis techniques made it possible to produce such defined oligopeptides with high purity and reproducibility. Once synthesized, Fequesetide could be evaluated independently of the full-length protein, allowing researchers to study structure–function relationships at a more detailed level. This approach has been widely used in peptide science to clarify how short amino acid sequences contribute to the biological activity of much larger proteins.

In terms of application, Fequesetide has primarily been used as a biochemical and cell biology research tool. Because it represents a portion of an actin-binding domain, it has been employed in experimental systems designed to probe actin dynamics, cytoskeletal organization, and cell migration. Studies using peptide fragments of thymosin beta proteins have shown that such sequences can influence actin sequestration and polymerization in vitro, and can modulate cellular behavior in controlled experimental settings. Fequesetide is therefore applied not as a therapeutic agent or industrial chemical, but as a probe to help clarify molecular mechanisms underlying cytoskeletal regulation.

In biomedical research contexts, peptides related to thymosin beta proteins have attracted interest because of their involvement in processes such as wound healing, angiogenesis, and cell motility. Fequesetide, as a defined fragment, has been used to support mechanistic studies in these areas by isolating the contribution of a specific sequence. Its use allows researchers to avoid the complexity of full-length proteins and to focus on localized interactions at the molecular level. However, Fequesetide itself is not approved for clinical use and is not described in the literature as a drug or diagnostic agent.

Overall, Fequesetide exemplifies how advances in peptide synthesis and protein chemistry have enabled the creation of precise molecular tools derived from biologically active proteins. Its discovery is rooted in the broader exploration of thymosin beta peptides and actin biology, while its applications are confined to experimental research aimed at understanding cytoskeletal regulation and related cellular processes.