Direct quantification of protein glycan phosphorylation

Area of Science:

• Biochemistry
• Analytical Chemistry
• Protein Science

Background:

• Phosphorylation is a key post-translational modification (PTM) crucial for protein function and therapeutic efficacy.
• Existing methods for phosphorylation quantification are often complex, indirect, or require specialized equipment.
• Accurate assessment of phosphorylation is vital for quality control of protein-based therapeutics.

Purpose of the Study:

• To develop and validate a simplified method for quantifying protein phosphorylation.
• To adapt a phosphate-specific binding dye for measuring phosphorylation on both glycans and protein backbones.
• To assess the reliability of this new method by comparing results with established data.

Main Methods:

• Utilized a phosphate-specific binding dye with common laboratory instruments.
• Applied the method to quantify relative amounts of phosphorylated glycans.
• Assessed phosphorylation of amino acid residues on protein backbones.

Main Results:

• The developed method successfully quantified phosphorylation on glycans and protein amino acid residues.
• Results for phosphorylated glycosylation sites on lysosomal enzymes (GUS and cathepsin D) aligned with published data.
• Demonstrated the utility of the dye-based approach for relative phosphorylation quantification.

Conclusions:

• The adapted dye-based method offers a more accessible approach for quantifying protein phosphorylation.
• This technique can be valuable for assessing critical quality attributes of protein therapeutics.
• The method provides reliable quantification of phosphorylation, comparable to existing data.