Cys-TAT (47-57) Cell-Penetrating Peptide – Catalog #B2026688

Cys-TAT (47-57) is a peptide fragment from the HIV-1 TAT (transactivator of transcription) protein, spanning amino acids 47–57, with an N-terminal cysteine residue for chemical conjugation. This arginine-rich sequence is a prototypical cell-penetrating peptide (CPP) that crosses cell membranes efficiently and is widely used to deliver molecular cargo—proteins, peptides, oligonucleotides, and nanoparticles—into living cells.

Scientific Overview

The TAT protein from HIV-1 is a regulatory protein essential for viral transcription. The minimal cell-penetrating domain spans approximately amino acids 47–57, a sequence rich in positively charged arginine residues. This short motif, often called the TAT peptide or TAT-peptide, is one of the most studied CPPs; it crosses plasma membranes via macropinocytosis and other endocytic pathways and can traffic to the nucleus. The cysteine residue at the N terminus permits covalent attachment of payloads via thiol-reactive chemistry (e.g., maleimide coupling, disulfide formation).

Key applications include:

• Intracellular delivery of proteins, peptides, and enzymes
• Cell-penetrating vector for therapeutic oligonucleotides and siRNA
• Nanoparticle targeting and cellular uptake enhancement
• Transduction domain for research and tool proteins
• Mechanistic studies of cell membrane permeability and endocytosis

Usage & Handling Guidance

Resuspend the lyophilized powder in water or physiological buffer (PBS, HBSS, culture medium) immediately before use. TAT peptides are stable over a range of pH and ionic strength but are sensitive to proteolysis in serum and cell culture media; if studying cellular uptake, include protease inhibitors or use serum-free conditions. The cysteine can be oxidized to a disulfide dimer under oxidizing conditions or conjugated to thiol-reactive molecules (e.g., maleimide-activated carriers, activated esters).

• Reconstitution: Dissolve in sterile water or buffer to desired concentration (μM to mM range typical for cell studies).
• Conjugation: Use maleimide or other thiol-reactive chemistry to couple payloads to the N-terminal cysteine.
• Purity: Request a lot-specific COA/TDS for amino acid composition and HPLC purity data.

What You Get

• 1 mg of Cys-TAT (47-57) peptide, supplied as lyophilized powder
• Molecular weight 1661.99 Da
• Cysteine-functionalized for payload conjugation
• For research use only (RUO)

Why Researchers Choose It

• Prototypical cell-penetrating peptide with decades of literature validation
• Efficient, non-toxic membrane crossing via endocytosis and other pathways
• N-terminal cysteine enables site-specific conjugation chemistry
• Works in diverse cell types and delivery contexts
• Simple, cost-effective alternative to viral vectors for intracellular delivery

Frequently Asked Questions (FAQ)

• How does TAT cross cell membranes?
  TAT enters cells primarily via energy-dependent endocytosis (macropinocytosis) and can escape into the cytoplasm and traffic to the nucleus.
• Can I conjugate a cargo to the cysteine?
  Yes. Use maleimide-activated carriers, disulfide coupling, or other thiol-reactive chemistry to attach your payload.
• How much peptide do I need?
  Start with 1–10 μM in your assay; some applications use up to 100 μM. Optimize for your cell type and cargo.
• Is this TAT peptide affected by serum?
  TAT is sensitive to protease degradation in serum and cell culture medium. Use serum-free conditions or protease inhibitors if studying cellular uptake over time.
• How should I store the lyophilized powder?
  At −20°C or below, protected from moisture. Once reconstituted, aliquot and store at −20°C or keep on ice during use.

References

• Schmidt N, Mishra A, Lai GH, Wong GC. Arginine-rich cell-penetrating peptides. FEBS Lett. 2010;584(9):1806-13.
• Zou L, Peng Q, Wang P, Zhou B. Progress in Research and Application of HIV-1 TAT-Derived Cell-Penetrating Peptide. J Membr Biol. 2017;250(2):115-122.
• Rizzuti M, Nizzardo M, Zanetta C, Ramirez A, Corti S. Therapeutic applications of the cell-penetrating HIV-1 Tat peptide. Drug Discov Today. 2015;20(1):76-85.
• Chauhan A, Tikoo A, Kapur AK, Singh M. The taming of the cell penetrating domain of the HIV Tat: myths and realities. J Control Release. 2007;117(2):148-62.