Pep-20-D12 peptide

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

Batch to batch variation of the purity

Pep-20-D12 is a D-amino acid-substituted derivative of the CD47-binding peptide pep-20, which was identified through high-throughput phage display library bio-panning. Pep-20 binds to both human and mouse CD47-IgV domains with KD values of approximately 2.91 μM and 3.63 μM, respectively, and blocks the CD47/SIRPα interaction with IC50 values of 24.56 μM (human) and 12.03 μM (mouse). Alanine scanning and molecular docking indicate that residues W2, W6, Y9, and W10 contribute to CD47 binding, with the interaction interface overlapping the natural CD47/SIRPα contact region. Pep-20-D12 carries D-amino acid substitutions at both the N-terminal and C-terminal regions, which confer resistance to enzymatic degradation in human serum while preserving the CD47/SIRPα blocking activity of the parent peptide.

Functionally, pep-20-D12 disrupts CD47/SIRPα signaling, thereby reducing SIRPα tyrosine phosphorylation and enhancing macrophage-mediated phagocytosis of tumor cells. This phagocytic activity promotes antigen presentation and stimulates CD8+ T cell responses, including increased intratumoral CD8+ T cell infiltration and IFN-γ production. The enhanced proteolytic stability of pep-20-D12 relative to pep-20 supports sustained activity in systemic contexts, and its combination with irradiation further augments tumor infiltration by macrophages and monocyte-derived cells, resulting in synergistic antitumor effects in mouse tumor models.

• Wang H, Sun Y, Zhou X, Chen C, Jiao L, Li W, Gou S, Li Y, Du J, Chen G, Zhai W, Wu Y, Qi Y, Gao Y. CD47/SIRPα blocking peptide identification and synergistic effect with irradiation for cancer immunotherapy. J Immunother Cancer. 2020 Oct;8(2):e000905. doi: 10.1136/jitc-2020-000905. PMID: 33020240; PMCID: PMC7537338.

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.