PTD-p65-P1 peptide

• Handling and Storage of Synthetic Peptides
• Material Safety Data Sheets (MSDS)

Batch to batch variation of the purity

The PTD-p65-P1 peptide is derived from the p65 subunit of NF-κB, specifically targeting amino acid residues 271–282, which include the phosphorylation site Ser276. This peptide is linked to a protein transduction domain (PTD) from the third helix sequence of antennapedia, enabling efficient cellular uptake. PTD-p65-P1 selectively inhibits NF-κB activation by blocking p65 phosphorylation and nuclear translocation without affecting IκBα degradation or IKK activation. It suppresses NF-κB DNA binding and downstream gene expression, demonstrating specificity by not interfering with AP-1 activation. The peptide's mechanism involves competitive inhibition of p65 phosphorylation, crucial for NF-κB transcriptional activity.

In vitro studies show that PTD-p65-P1 directly inhibits recombinant p65 binding to DNA, independent of PTD linkage. The peptide's efficacy is sequence-dependent, requiring intact Ser276 for function. PTD-p65-P1 broadly inhibits NF-κB activation induced by diverse stimuli, including TNF, LPS, and oxidative stress, indicating action at a convergent pathway step. Its ability to modulate NF-κB-dependent processes highlights its utility as a molecular tool for studying NF-κB signaling.

• Takada Y, Singh S, Aggarwal BB. Identification of a p65 peptide that selectively inhibits NF-kappa B activation induced by various inflammatory stimuli and its role in down-regulation of NF-kappaB-mediated gene expression and up-regulation of apoptosis. J Biol Chem. 2004 Apr 9;279(15):15096-104. doi: 10.1074/jbc.M311192200. Epub 2004 Jan 7. PMID: 14711835.

Trifluoroacetic acid (TFA) is a common counterion from the purification process using High-Performance Liquid Chromatography (HPLC). The presence of TFA can affect the peptide's net weight, appearance, and solubility.

Impact on Net Weight: The TFA salt contributes to the total mass of the product. In most cases, the peptide content constitutes >80% of the total weight, with TFA accounting for the remainder.

Solubility: TFA salts generally enhance the solubility of peptides in aqueous solutions.

In Biological Assays: For most standard in vitro assays, the residual TFA levels do not cause interference. However, for highly sensitive cellular or biochemical studies, please be aware of its presence.