Cys(Npys)-TAT (47-57)

Product Name: Cys(Npys)-TAT (47-57)

Sequence One Letter Code: C(Npys)YGRKKRRQRRR-NH2

Sequence Three Letter Code: Cys(Npys)-Tyr-Gly-Arg-Lys-Lys-Arg-Arg-Gln-Arg-Arg-Arg-NH2

Chemical Formula:C72H126N36O16S2

Molecular Weight: 1816.1

Purity: 95%

Form: Lyophilized

Storage Conditions: - 20 °C

Research Area: Cell Penetrating Peptides

Source / Species: HIV

Conjugation: Unconjugated

Code Nacres: NA.26

Application: Cys(Npys)-TAT (47–57) is derived from the well-characterized protein transduction domain of the HIV-1 TAT protein and represents one of the most widely studied cell-penetrating peptides. The arginine-rich TAT (47–57) sequence enables efficient direct penetration of the plasma membrane and facilitates intracellular delivery of various biomolecules. The peptide contains an Npys-activated cysteine residue, which allows rapid and selective conjugation with thiol-containing molecules through disulfide exchange reactions. This feature makes Cys(Npys)-TAT (47–57) highly suitable for carrier and delivery applications. The peptide is commonly used in conjugation chemistry, intracellular transport studies, and the development of delivery systems for peptides, proteins, nucleic acids, and other bioactive molecules in cell biology and biomedical research.

Current Research: Cell-penetrating peptides (CPPs) are short peptide sequences capable of crossing cellular membranes and transporting various biomolecules into cells. Among the most extensively studied CPPs is the TAT (47–57) peptide, derived from the protein transduction domain of the HIV-1 trans-activator of transcription (TAT) protein. This arginine-rich peptide sequence has become a widely used molecular tool for studying intracellular delivery mechanisms and cargo transport in cell biology. Cys(Npys)-TAT (47–57) is a modified version of this peptide that includes an Npys-activated cysteine residue. This modification enables efficient conjugation with thiol-containing molecules, making the peptide particularly valuable for bioconjugation strategies and targeted intracellular delivery systems. Because of its dual functionality—membrane penetration and selective conjugation—Cys(Npys)-TAT (47–57) has become a versatile reagent in biochemical and biomedical research. The TAT (47–57) Cell-Penetrating Domain The TAT (47–57) peptide corresponds to the minimal protein transduction domain (PTD) of the HIV-1 TAT protein. This short sequence is rich in basic amino acids, particularly arginine and lysine, which give the peptide a strong positive charge. This cationic character allows the peptide to interact with negatively charged components of the cell membrane, such as glycosaminoglycans and phospholipid head groups. Through these interactions, the peptide can facilitate cellular uptake through mechanisms that may include: Direct membrane translocation Endocytosis-mediated uptake Macropinocytosis pathways Because of its ability to efficiently cross biological membranes, the TAT peptide has become one of the most widely used CPPs for delivering proteins, peptides, nucleic acids, and nanoparticles into cells. Role of the Npys-Activated Cysteine A defining feature of Cys(Npys)-TAT (47–57) is the N-terminal cysteine residue protected with an Npys (3-nitro-2-pyridinesulfenyl) group. This functional group serves as an activated disulfide intermediate that enables rapid and selective conjugation with thiol-containing molecules. The Npys group facilitates disulfide exchange reactions, allowing the peptide to form reversible disulfide bonds with cysteine residues present in target molecules. This chemistry is highly useful in experimental settings because it allows researchers to attach the TAT peptide to various cargo molecules in a controlled manner. Key advantages of the Npys modification include: Efficient thiol-specific conjugation Formation of reversible disulfide linkages Mild reaction conditions suitable for biological molecules High selectivity toward cysteine-containing targets These properties make Cys(Npys)-TAT (47–57) particularly valuable for constructing peptide–cargo conjugates used in intracellular delivery experiments. Applications in Intracellular Transport Studies One of the most important uses of Cys(Npys)-TAT (47–57) is in studies of intracellular transport and cellular uptake mechanisms. By attaching the peptide to experimental cargo molecules, researchers can investigate how macromolecules enter cells and how they are trafficked within intracellular compartments. Typical cargo molecules used in these studies include: Peptides and proteins Fluorescent probes Nucleic acids such as DNA or RNA Small-molecule inhibitors or signaling molecules The TAT sequence enables efficient cellular entry, allowing researchers to analyze intracellular localization, trafficking pathways, and functional activity of delivered molecules. Use in Conjugation Chemistry and Delivery Systems Because of the Npys-activated cysteine residue, this peptide is frequently used in bioconjugation chemistry. The ability to selectively link the peptide to thiol-containing molecules makes it a convenient platform for constructing targeted delivery systems. Examples of experimental applications include: Generation of protein–peptide conjugates for cellular delivery Development of nucleic acid delivery systems Attachment of fluorescent tags for imaging studies Construction of peptide-based delivery vectors These applications are especially important in biomedical research where efficient intracellular transport of macromolecules is required. Relevance in Biomedical and Cell Biology Research The combination of membrane-penetrating ability and conjugation flexibility makes Cys(Npys)-TAT (47–57) a powerful experimental tool in multiple areas of research. Scientists frequently use this peptide to explore: Mechanisms of cellular uptake Intracellular protein delivery strategies Peptide-based transport systems Biomolecule trafficking within cells These studies contribute to a deeper understanding of how biological molecules interact with cellular membranes and how engineered peptides can facilitate controlled delivery into living cells. Conclusion Cys(Npys)-TAT (47–57) is a modified version of the well-known TAT cell-penetrating peptide that incorporates an Npys-activated cysteine for thiol-specific conjugation. The arginine-rich TAT sequence enables efficient cellular penetration, while the Npys modification allows selective attachment to thiol-containing cargo molecules through disulfide exchange reactions. Because of these combined properties, the peptide is widely used in bioconjugation chemistry, intracellular transport studies, and the development of delivery systems for peptides, proteins, nucleic acids, and other bioactive molecules. As research into cellular delivery technologies continues to advance, Cys(Npys)-TAT (47–57) remains an important tool for exploring membrane translocation mechanisms and intracellular cargo transport.