Cerium ions immobilized magnetic graphite nitride decorated with L-Alanyl-L-Glutamine as new chelator for enrichment of phosphopeptides

Abstract

Cerium ions immobilized magnetic graphite nitride material have been prepared using L-Alanyl-L-Glutamine as the new chelator. The resulting Fe₃O₄/g-C₃N₄-L-Ala-L-Gln-Ce⁴⁺, as an immobilized metal ion affinity chromatography (IMAC) sorbent, was reusable. This is due to the strong coordination interaction between L-Alanyl-L-Glutamine and cerium ions. After a series of characterizations, the magnetic nanocomposite showed high surface area, good hydrophilicity, positive electricity, and magnetic response. Fe₃O₄/g-C₃N₄-L-Ala-L-Gln-Ce⁴⁺ had high sensitivity (0.1 fmol), selectivity (α-/β-casein/bovine serum albumin, 1:1:5000), and good recyclability (10 cycles). A total of 647 unique phosphopeptides mapped to 491 phosphoproteins were identified from A549 cell lysate by nano LC-MS analysis.

Keywords: Anion-exchange chromatography; Immobilized metal affinity chromatography; MALDI TOF–MS; Magnetic nanocomposite; Phosphoproteomics.