EPQpYEEIPIYL peptide

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

Batch to batch variation of the purity

The phosphopeptide EPQpYEEIPIYL is a high-affinity ligand for the Src homology 2 (SH2) domain of the Lck tyrosine kinase. This peptide binds with high specificity to the Lck SH2 domain, primarily through interactions involving the phosphotyrosine (pTyr) residue and the hydrophobic pocket accommodating the Ile at the pY+3 position. The Glu at the pY+1 position is sensitive to substitution, while residues at pY+2 and pY+4 exhibit minimal impact on binding affinity. Structural studies reveal that the pY+3 Ile inserts into a deep hydrophobic pocket, whereas the pY+1 Glu lies across the SH2 domain surface. Despite predictions from crystal structures, solution binding studies indicate some flexibility in accommodating nonconservative substitutions, suggesting dynamic interactions in physiological conditions.

• Payne G, Stolz LA, Pei D, Band H, Shoelson SE, Walsh CT. The phosphopeptide-binding specificity of Src family SH2 domains. Chem Biol. 1994 Oct;1(2):99-105. doi: 10.1016/1074-5521(94)90047-7. PMID: 9383377.

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.