The monofunctional mitochondrial and peroxisomal enzymes are found in the mitochondria and peroxisomes of eukaryotes, respectively. The multifunctional enzymes are found in bacteria and in the peroxisomes of some eukaryotes, but they serve two functions: the N-terminal domain works the same as the other classes of enoyl-CoA isomerases and the C-terminal domain works as a dehydrogenase, specifically, to 3-hydroxyactyl-CoA. There are two divisions among the mitochondrial enoyl Co-A isomerase: short-chain and long-chain . In an immunoblot, antibodies were run against all enoyl CoA isomerase. However, two of these isomerases had antibody attachment: the short chain isomerase and the peroxisomal multifunctional enzyme. There was one enzyme which did not have binding specificity to this antibody: mitochondrial long-chain isomerase. Long-chain isomerase was found when it eluted at a lower potassium phosphate concentration in the gradient. Thus, the discovery of three sub-classes of enoyl CoA isomerase was made.