Enrichment of Low-Abundance Peptides and Proteins on Zeolite Nanocrystals for Direct MALDI-TOF MS Analysis

摘要

Proteomics, one of the most important research areas in the post genomics era, is arousing considerable attention because of its pertinence to functional genomics.[1] Its premise is the high-throughput separation and identification of proteins and peptides. Peptide mapping by MALDI-TOF MS has become a major tool for protein identification in proteome analysis.[2] However, many proteins are quite scarce owing to the difficulties of sample isolation. This is especially true for proteins that are expressed in low abundance, such as disease-associated proteins.[3] Moreover, a further decrease in sample yield may occur during the preparation of a peptide digest prior to MALDI-TOF MS analysis which therefore requires that peptide preparations undergo an enrichment step beforehand. However, conventional methods for concentrating peptides by simple evaporation result in sample loss through protein adsorption onto the surface of the container. An additional problem with evaporation is the simultaneous concentration of buffer components (e.g. salts) and other contaminants. Alternative methods for peptide enrichment by reversed-phase resin are complex and are typically suitable only for hydrophobic peptides.[4] Therefore a universal and simple peptide enrichment method is in high demand.