Optimized sample treatment protocol by solid-phase peptide libraries to enrich for protein traces

Combinatorial peptide ligand libraries have been extensively used for the enrichment of very low-abundance proteins, while concomitantly reducing the concentration of major species. A number of biological extracts have been reported with great success. Nevertheless, there are examples where the enrichment was not as good as expected. It has been demonstrated that the protocol itself may be responsible for the final results and is not necessarily applied as it should. In this paper, technical details along with important suggestions are given for an optimized enrichment of gene products present at trace levels among very many other proteins.