Description
Binds heme (iron protoporphyrin IX) and tetrahydrobiopterin. Most of the bacterial and archaeal enzymes consist of only an oxidase domain and function together with bacterial ferredoxins. The enzyme from the Δ-proteobacterium Sorangium cellulosum also includes a reductase domain that binds FAD, FMN and a [2Fe-2S] cluster. The similar enzymes from plants and animals use only NADPH as acceptor (cf. EC 1.14.13.39)