Gp100 (25-33), human peptide

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Batch to batch variation of the purity

The Gp100 (25-33), human peptide is a 9-amino acid epitope (KVPRNQDWL) derived from the glycoprotein 100 (gp100) melanoma-associated antigen. This peptide is restricted by the MHC class I molecule H-2D^b and serves as a target for cytotoxic T lymphocytes (CTLs). The human version of this peptide exhibits significantly higher binding affinity to H-2D^b compared to its murine counterpart (EGSRNQDWL), due to differences in the three NH₂-terminal amino acids. This enhanced binding results in greater stability of peptide-MHC complexes and more efficient T cell recognition.

Structural analysis reveals that the human Gp100 (25-33) peptide contains optimal anchor residues at positions 5 (N) and 9 (L) for H-2D^b binding. The NH₂-terminal residues (KVP in human vs EGS in mouse) contribute to the differential MHC binding affinity, with the human peptide showing approximately 100-fold greater stabilization of H-2D^b molecules. The core sequence RNQDWL (positions 4-9) represents the TCR contact region, as substitutions in these positions abrogate T cell recognition while modifications in the NH₂-terminal residues maintain immunogenicity.

• Overwijk WW, Tsung A, Irvine KR, Parkhurst MR, Goletz TJ, Tsung K, Carroll MW, Liu C, Moss B, Rosenberg SA, Restifo NP. gp100/pmel 17 is a murine tumor rejection antigen: induction of "self"-reactive, tumoricidal T cells using high-affinity, altered peptide ligand. J Exp Med. 1998 Jul 20;188(2):277-86. doi: 10.1084/jem.188.2.277. PMID: 9670040; PMCID: PMC2212458.

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.