Description | The N(5),N(10)-methylenetetrahydromethanopterin dehydrogenase system of methanogenic archaea is composed of H2-forming methylenetetrahydromethanopterin dehydrogenase (Hmd, ) and F420-dependent methylenetetrahydromethanopterin dehydrogenase ( ) [ , ]. Hmd is an iron-sulphur-cluster-free enzyme that contains an intrinsic CO ligand bound to iron []. The Hmd enzymes can be divide into two distinct subgroups: one has been experimentally characterised as H2-forming N(5),N(10)-methenyltetrahydromethanopterin dehydrogenase (Hmd or HmdI), and the other one contains isozymes that have not been experimentally characterised (HmdII and HmdIII). Because all three isozyme forms are present in each of the corresponding sequenced genomes, it has been suggested that HmdII and HmdIII may not exhibit Hmd activity and may have a different biological function [].This entry represents the experimentally characterised (HmdI) subgroup of the N(5),N(10)-methylenetetrahydromethanopterin dehydrogenases. | Name | 5,10-methenyltetrahydromethanopterin hydrogenase |
Short Name | HMD_ | Type | Family |