Dehydratases are a group of lyase enzymes that form double and triple bonds in a substrate through the removal of water.[1] They can be found in many places including the mitochondria, peroxisome and cytosol.[2] There are more than 150 different dehydratase enzymes[3] that are classified into four groups. Dehydratases can act on hydroxyacyl-CoA with or without cofactors, and some have a metal and non-metal cluster act as their active site.[citation needed]