This laboratory exercise uses a problem-based approach to expose students to some basic concepts relating to proteins and enzymes. One of the main applications of enzymes at the industrial level is their use in the detergent market. The students examine a detergent sample to ascertain whether proteolytic enzymes are a component and, if so, which colored detergent granules contain them. A 4-hour standard exercise is described that can be easily modified to study a number of conditions that affect enzymatic activity. The students also become familiar with polyacrylamide gel electrophoresis as it is used to visualize the products of enzyme activity. (Contains 4 figures.)