Dehydrogenases are studied for a variety of reasons. Several dehydrogenases are of use in industrial processes to produce pharmaceuticals and fine chemicals. Scientists are trying to enhance the performance of such enzymes by limiting substrate inhibition (1 ) and eliminating the need for expensive activators (2 ). In addition, dehydrogenases are involved in alcohol metabolism (3 ), and in mammalian cell growth (4 ) and cell death (5 ). Various dehydrogenases have been implicated in diseases and cancers (6 –9 ) and have therefore become important targets for antiparasitic and anticancer drugs (10 ). High-throughput screens for dehydrogenase activity are expected to be useful in many of these studies.