An experiment was designed so that students learn biochemical concepts in addition to the technique and theory of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). At the start of the lab, students are given stock solutions of four proteins with different subunit compositions: carbonic anhydrase (α), glyceraldehyde 3-phosphate dehydrogenase (α4), hemoglobin (α2β2), and superoxide dismutase (α2). Half of the student pairs mix their samples with buffer containing βME and urea while the rest of the student pairs use buffer without βME and urea. Student assessment of the experiment during fall semester 2002 revealed that majority of the students believe that the goals of the experiment and the instructions are clear. Students reported a better understanding of gel electrophoresis and protein subunit composition.