Highly specific phosphopeptide enrichment by titanium(IV) cross-linked chitosan composite

Area of Science:

• Biochemistry
• Analytical Chemistry
• Materials Science

Background:

• Phosphopeptide enrichment is crucial for studying protein phosphorylation.
• Existing immobilized metal ion affinity chromatography (IMAC) methods can involve complex synthesis procedures.
• Chitosan is a biocompatible and abundant natural polymer with potential as a chromatographic support.

Purpose of the Study:

• To develop a novel, easily synthesized Ti(IV) based immobilized metal ion affinity chromatography (IMAC) material using natural chitosan (Ti-CTS).
• To evaluate the efficiency of Ti-CTS for phosphopeptide enrichment from complex biological samples.
• To investigate the affinity of Ti-CTS for multi-phosphorylated peptides.

Main Methods:

• Synthesis of Ti-CTS material using natural chitosan and Ti(IV).
• Characterization of Ti-CTS using scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), and X-ray photoelectron spectroscopy (XPS).
• Enrichment of tryptic digest products from standard proteins, non-fat milk, and human serum using Ti-CTS.

Main Results:

• Ti-CTS exhibited favorable morphology, surface area, and pore volume.
• The composite demonstrated high sensitivity and selectivity for phosphopeptide enrichment.
• Ti-CTS showed high affinity for multi-phosphorylated peptides, including those with three serine phosphorylation sites (S*S*S*).

Conclusions:

• Ti-CTS provides a simplified and effective method for phosphopeptide enrichment.
• This material holds significant potential for the analysis of complex phosphoproteomes, particularly multi-phosphorylated peptides.
• The developed Ti-CTS material offers a promising tool for advancing phosphoproteomics research.