Acyl-CoA dehydrogenases and acyl-CoA oxidases

Acyl-CoA dehydrogenases and acyl-CoA oxidases are two closely related FAD-containing enzyme families that are present inmitochondria andperoxisomes, respectively. They catalyze the dehydrogenation of acyl-CoA thioesters to the corresponding trans-2-enoyl-CoA. This review examines the structure of medium chain acyl-CoA dehydrogenase, as a representative of the dehydrogenase family, with respect to the catalytic mechanism and its broad chain length specificity. Comparing the structures of four other acyl-CoA dehydrogenases provides further insights into the structural basis for the substrate specificity of each of these enzymes. In addition, the structure of peroxisomal acyl-CoA oxidase II from rat liver is compared to that ofmediumchain acyl-CoA dehydrogenase, and the structural basis for their different oxidative half reactions is discussed.