Ion-exchange chromatography is often introduced in student experiments because it is an excellent method to enhance understanding of the principles underlying protein handling and purification. In our second-year student experiment at Nagahama Institute of Bio-Science and Technology, we isolated lysozyme from three-protein mixtures using cation exchange chromatography. Lysozyme was identified through absorbance at 280 nm, bacteriolytic activity, and SDS-PAGE. Unexpectedly, the absorbance chromatogram and the activity chromatogram of lysozyme did not align. Bacteriolytic activity was apparently reduced in the fraction containing the highest lysozyme concentration compared to adjacent fractions. This phenomenon is attributed to the formation of a complex between lysozyme and lysed bacteria, leading to precipitation. In response to this observation, we introduced an experiment in which the dissolution of these sediments was facilitated by adding an alkaline solution after lysis. This step resulted in an increase in solution transparency known as the Nakamura effect. As a result, students developed a heightened interest in and a deeper understanding of protein electrostatics and charge.