The enzyme orotidine-5'-monophosphate decarboxylase is an attractive choice for the central theme of an integrated, research-based biochemistry laboratory course. A series of laboratory exercises common to most instructional laboratories, including enzyme assays, protein purification, enzymatic characterization, elementary kinetics, and recombinant DNA methods, has been devised. The series of exercises requires biochemical instrumentation common to most laboratories and some specialized materials available from the author's institution to laboratory instructors. (Contains 3 figures.)