Characterization of protein conjugates using capillary electrophoresis

Area of Science:

• Bioconjugation Chemistry
• Analytical Chemistry
• Immunology

Background:

• Antibody generation often requires coupling haptens to carrier proteins.
• Characterizing the extent of hapten conjugation is crucial for antibody quality.
• Hydrophobic haptens present unique challenges in conjugation and characterization.

Purpose of the Study:

• To develop and optimize a capillary electrophoresis (CE) method for characterizing the coupling of hydrophobic haptens.
• To establish a relationship between electrophoretic mobility and hapten density.
• To determine the average coupling molar ratio and assess the heterogeneity of protein-hapten conjugates.

Main Methods:

• Coupling of calix[4]arene-crown-6 to bovine serum albumin.
• Development of a capillary electrophoresis (CE) procedure for optimization and characterization.
• Analysis of electrophoretic mobility (mu(ep)) as a function of hapten density.
• Simulation of experimental peaks to estimate conjugate heterogeneity.

Main Results:

• A polynomial relationship was demonstrated between electrophoretic mobility and hapten density.
• The developed CE method allowed for the optimization and kinetic study of the coupling reaction.
• The average coupling molar ratio of conjugates was determined.
• A method for estimating the heterogeneity of conjugates was proposed.

Conclusions:

• Capillary electrophoresis (CE) provides a robust method for optimizing and characterizing hydrophobic hapten-protein conjugation.
• The established correlation between electrophoretic mobility and hapten density enables precise quantification of conjugation.
• This approach facilitates the development of well-characterized conjugates for antibody generation.