Synthesis of peptide analogues using the multipin peptide synthesis method

Modification of the multipin peptide synthesis method which allows the simultaneous synthesis of large numbers of different peptide analogues is described. Peptides were assembled on polyethylene pins derivatized with a 4-(beta-alanyloxymethyl)benzoate (beta-Ala-HMB) handle. For comparative purposes, peptides were also assembled on the diketopiperazine-forming handle N epsilon-(beta-alanyl)lysylprolyloxylactate. In model studies it was demonstrated that beta-Ala-HMB-linked peptides were cleaved from polyethylene pins with dilute sodium hydroxide or 4% methylamine/water to yield analogues with beta-Ala-free acid (beta-Ala-CO2H) and beta-Ala-methylamide (beta-Ala-CONHCH3), respectively. To assess the suitability of this approach for T-cell determinant analysis, analogues of a known T-cell determinant were synthesized with the various C-terminal endings. Peptides were characterized by amino acid analysis and fast atom bombardment-mass spectrometry. HPLC of the crude cleaved peptides indicated that 22 of the 24 peptides were greater than 95% pure. These crude peptide solutions were nontoxic in sensitive cell culture assays without further purification. All three cleavage procedures gave comparable activities in T-cell proliferation assays. These results demonstrate the potential of the multipin peptide synthesis method for the production of large numbers of different peptide analogues.