Selective, bead-based global peptide capture using a bifunctional cross-linker.

Peptides are important species for a variety of biological functions. Detection and analysis of these molecules can be complicated by the presence of background matrix or contaminants. Therefore, a selective method to capture peptides could provide researchers with an option to isolate these remarkable species. Our goal was to perform a set of experiments that would validate the concept of a novel, selective peptide capture, whereby peptides are isolated on functionalized magnetic beads through the use of the heterobifunctional cross-linker, Sulfo-LC-SPDP. Matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used to monitor mass changes associated with the cross-linking reaction. MALDI-TOF MS was then used to monitor conjugation between the cross-linked peptides and sulfhydryl magnetic beads by analyzing supernatant solutions for the presence or absence of cross-linked peptide. Through these experiments, we have proof of concept data confirming that peptides can be isolated on sulfhydryl magnetic beads by using Sulfo-LC-SPDP. This method is a suitable selective global peptide isolation strategy to separate the molecules from contaminating species or sample matrix. This novel method has a variety of potential applications and detection methods.