Dihydroorotate dehydrogenase (DHOD) class 2. DHOD catalyzes the oxidation of (S)-dihydroorotate to orotate. This is the fourth step and the only redox reaction in the de novo biosynthesis of UMP, the precursor of all pyrimidine nucleotides. DHOD requires FMN as co-factor. DHOD divides into class 1 and class 2 based on their amino acid sequences, their cellular location and their natural electron acceptor used to reoxidize the flavin group. Members of class 1 are cytosolic enzymes and multimers, while class 2 enzymes are membrane associated, monomeric and use respiratory quinones as their physiological electron acceptors.
Jiyao W et al.(2023). "The conserved domain database in 2023.",