Facile synthesis of titanium(IV) ion‐immobilized poly‐glycidyl methacrylate microparticles functionalized with polyethylenimine and adenosine triphosphate for highly specific enrichment of intact phosphoproteins.

In this study, a facile synthesis of the titanium(IV) ion‐immobilized poly‐glycidyl methacrylate microparticles functionalized with polyethylenimine and adenosine triphosphate was developed for efficient enrichment of intact phosphoproteins. The titanium(IV) ion‐immobilized microparticles had higher saturated adsorption capacity for phosphoproteins (1217.6 mg/g for β‐casein) than nonphosphoproteins (97.1 mg/g for bovine serum albumin) and the average particle diameter was about 1.4 μm with good dispersibility. In application, as demonstrated by SDS‐PAGE, titanium(IV) ion‐immobilized microparticles exhibited good performance in enriching intact phosphoproteins from standard protein mixtures of β‐casein and bovine serum albumin with high specificity and selectivity. In addition, titanium(IV) ion‐immobilized microparticles were also successfully applied in intact phosphoprotein enrichment from complex biological samples including nonfat milk, chicken egg white, and mouse heart tissue extract. [ABSTRACT FROM AUTHOR]