| Type: | Family | Name: | Propanediol/glycerol dehydratase, small subunit |
| Description: | Diol dehydratase () and glycerol dehydratase () are two iso-functional enzymes that can each catalyse the conversion of 1,2-propanediol, 1,2-ethanediol and glycerol to the corresponding deoxy aldehydes (propionaldehyde, acetaldehyde and 3-hydroxypropionaldehyde, respectively). This reaction proceeds by a radical mechanism involving coenzyme B12 (adenosylcobalamin, AdoCbl) as an essential cofactor. Even though they catalyse the same reaction, these two enzymes (1) differ in their substrate preferences (diol dehydratase has a higher affinity for 1,2-propanediol and glycerol dehydratase for glycerol []); (2) they participate in different pathways (dihydroxyacetone [DHA]pathway for glycerol dehydratase and 1,2-propanediol degradation pathway for diol dehydratase); and (3) in those organisms where both enzymes are produced (such as Klebsiella and Citrobacter), the genes for them are independently regulated: glycerol dehydratase is induced when Klebsiella pneumoniae grows in glycerol-containing medium, whereas diol dehydratase is fully induced when it grows in propane-1,2-diol-containing medium, but only slightly in the glycerol medium [, ]. Crystal structures, mechanism of action and structure-function relationship with the coenzyme B12 have been extensively studied for these enzymes []. Diol/glycerol dehydratases undergo inactivation during catalysis and require a reactivating factor. Propanediol dehydratase was found to be associated with and is believed to be encased in the proteinaceous shell of polyhedral organelles [].Both diol dehydratase and glycerol dehydratase comprise three subunits: PduC/PduD/PduE or PddA/PddB/PddC for propanediol dehydratase, and GldA/Gld/B/GldC or DhaB/DhaC/DhaE for glycerol dehydratase. This entry represents the small subunit PduE/PddC/GldC/DhaE. | Short Name: | Ppandiol/glycerol_DeHydtase_su |
