Isoelectric focusing is a technique used in biochemistry to separate proteins based on their isoelectric points (pI). In this process, a pH gradient is established in a gel or liquid medium, allowing proteins to migrate under an electric field. Each protein will move until it reaches a point where its net charge is zero, effectively focusing them at their specific pI. This method is particularly useful for analyzing complex protein mixtures and is often employed in conjunction with other techniques like two-dimensional gel electrophoresis. Isoelectric focusing helps researchers identify and characterize proteins, contributing to fields such as proteomics and biomedical research.