What technique is used to separate and identify complex proteins?

Immunoelectrophoresis is a powerful technique for separating and identifying proteins based on their size and charge while simultaneously applying an antibody to specifically detect a target protein. This technique combines the principles of electrophoresis and immunologic detection, allowing for the visualization of specific proteins within a complex mixture.

In immunoelectrophoresis, a sample containing proteins is first subjected to electrophoresis, separating the proteins based on their electrophoretic mobility. After separation, specific antibodies are applied, which will bind to the target proteins. This binding forms a visible precipitin line that can be analyzed to determine the presence and amount of specific proteins, aiding in diagnosis and research.

This method is particularly useful in clinical applications, such as detecting monoclonal proteins in conditions like multiple myeloma or identifying specific antibodies in autoimmune diseases. Its specificity and sensitivity make it a valuable tool in laboratory settings for protein analysis.