Development of erbium phosphate doped poly(glycidyl methacrylate/ethylene dimethacrylate) spin columns for selective enrichment of phosphopeptides

Abstract

In this study, a novel method for the highly selective enrichment of phosphopeptides using erbium phosphate doped poly(glycidyl methacrylate/ethylene dimethacrylate) spin columns is presented. Erbium phosphate was synthesized by precipitation from boiling phosphoric acid and incubated overnight in erbium chloride solutions. The resulting powder was embedded in a monolithic poly(glycidyl methacrylate/ethylene dimethacrylate) polymer. The monolith was synthesized in a spin column by radical polymerization. Erbium phosphate demonstrated a high affinity and selectivity for phosphopeptides due to the strong interaction of trivalent erbium ions with the phosphate groups of phosphopeptides. The high selectivity and performance of the designed spin columns were demonstrated by successfully enriching phosphopeptides from tryptically digested protein mixtures containing the model phosphoproteins α- and β-casein, bovine milk, and human saliva. By the implementation of several washing steps, unspecific components were removed and the enriched phosphopeptides were effectively eluted from the spin columns under alkaline conditions. The selective performance of the presented method was further demonstrated by the enrichment of two synthetic phosphopeptides, which were spiked in tryptically digested and dephosphorylated HeLa cell lysates at low ratios. Finally, the presented approach was compared to conventional phosphopeptide enrichment by titanium oxide and revealed higher recoveries for the erbium phosphate doped monoliths.

Development of magnetic ytterbium oxide core–shell particles for selectively trapping phosphopeptides

“…Particularly lanthanide metal ions and lanthanide oxides have successfully been applied in phosphoproteomics. 47,48 This can be explained by the strong preference of lanthanides for oxygen-containing anions like phosphates, with which they form very stable phosphoprotein complexes. 49 The immobilization of phosphopeptides is accomplished through bidentate ligand coordination.…”

“…Similar effects were previously reported by Xu et al for a-zirconium phosphate nanoplatelets (a-ZrPNs) 51 and Güzel et al for ErPO 4 based spin columns. 48 Regarding phosphopeptide enrichment, an effective and fast sample preparation protocol had to be optimized rst. Particularly, the pH was found to be a critical factor during the loading process.…”

Development of new lanthanide(iii) ion-based magnetic affinity materials for phosphopeptide enrichment

“…1,44–47 Recently, IMAC and MOAC materials containing these rare earth elements were also developed. 1,31,38,48–51 Using magnetic microparticles as the support, Li et al (2008) prepared an IMAC material by chelating Ce 4+ ions on magnetic microspheres with IDA and determined that these materials exhibited better enrichment capacity compared to Fe 3+ chelated magnetic microspheres. 52 In another study using cerium( iv ) ions, Wang et al (2014) attached Ce 4+ ions to Fe 3 O 4 @SiO 2 supports via poly (vinylphosphonic acid) (PVPA) and found the IMAC material to allow a rapid and selective determination of phosphopeptides in bio-molecules, thanks to the abundance of Ce 4+ ions in the structure.…”

Preparation of zirconium arsenate‐modified monolithic column for selective enrichment of phosphopeptides

“…In addition, the advantages of flexible synthesis, adjustable porosity, fast mass transport, and low column backpressure also make it an ideal substrate of IMAC adsorbent [39]. However, most of the reported polymer monolith-based IMAC materials required tedious and time-consuming post-modification approaches to introduce chelating groups into the monolithic column [40,41], and the employed chelators were mostly phosphate group [8,11,[41][42][43].…”