Small peptide libraries: combinatorial split-mix synthesis followed by combinatorial amino acid analysis of selected variants.

Peptides from small combinatorial libraries, covalently attached to polymeric TentaGel beads, can be directly sequenced using amino acid analysis. For libraries with restricted diversity, generated by the split-mix synthesis method, the amino acids on a selected single bead identified by pre-column derivatization with o-phthaldialdehyde (OPA) correlate directly with the sequence of a given peptide. This is shown on a tripeptide (343 different compounds) and a tetrapeptide (4096 different compounds) library. This method allows for rapid peptide sequence determination without relying on complex encoding strategies.