Over the last 8 years, we have run a class for 3 rd year chemistry majors at the University of Bristol, which uses the CHARMM molecular simulation package to teach students about the rearrangement of chorismate to prephenate, first in vacuum, and then catalysed by chorismate mutase. Chorismate mutase is a biosynthetic enzyme that is part of the pathway that results in the production of tyrosine, and is found in various non-animal species. The chemical mechanism of the reaction involves a Claisen rearrangement, illustrated in Figure , and is characterized by distinct conformational changes in the ring as the reaction progresses from reactant to transition state, and then to product. Progress along the reaction coordinate is straightforward to track visually by inspecting the cleavage of the ether bond as well as changes in the ring conformation. Transition state stabilization is an important factor in catalysis in this enzyme and the stabilization provided by the enzyme along the reaction coordinate can be calculated using standard quantum mechanical/molecular mechanical (QM/MM) techniques. By comparing their own results to those of their peers, the students are able to relate the degree of transition state stabilisation to the conformation of the enzyme, and thereby gain insight into the role that transition state stabilization plays in catalysis.