Electrophoretic separation of proteins via complexation with a polyelectrolyte

TL;DR

This paper proposes a novel protein separation method using electrophoretic focusing with polyelectrolytes, exploiting hidden charge differences to distinguish proteins with identical isoelectric points.

Contribution

It introduces a new separation parameter based on charge inversion caused by polyelectrolyte complexation, enhancing protein separation techniques.

Findings

Proteins with the same pI can be separated based on hidden charge differences.

Charge inversion by polyelectrolyte complexes enables new separation capabilities.

The method enhances standard isoelectronic focusing with additional selectivity.

Abstract

We suggest to augment standard isoelectronic focusing for separation of proteins in a gradient of pH by a similar focusing in the presence of a strongly charged polyelectrolyte (PE). Proteins which have the same isoelectric point but different "hidden" charge of both signs in pI point make complexes with PE, which focus in different pH. This is a result of charge inversion of such proteins by adsorbed PE molecules, which is sensitive to the hidden charge. Hence the hidden charge is a new separation parameter.