Formate oxidase, an enzyme of the glucose-methanol-choline oxidoreductase family, has a His-Arg pair and 8-formyl-FAD at the catalytic site.

Formate oxidase of Aspergillus oryzae RIB40 contains an 8-replaced FAD with molecular mass of 799 as cofactor. The ¹H-NMR spectrum of the cofactor fraction obtained from the enzyme indicated that the 8-replaced FAD in the fraction was 8-formyl-FAD, present in open form and hemiacetal form. The oxidation-reduction potentials of the open and hemiacetal forms were estimated by cyclic voltammetry to be -47 and -177 mV vs.

Crystallization and preliminary X-ray analysis of formate oxidase, an enzyme of the glucose-methanol-choline oxidoreductase family.

Formate oxidase (FOD), which catalyzes the oxidation of formate to yield carbon dioxide and hydrogen peroxide, belongs to the glucose-methanol-choline oxidoreductase (GMCO) family. FOD from Aspergillus oryzae RIB40, which has a modified FAD as a cofactor, was crystallized at 293 K by the hanging-drop vapour-diffusion method. The crystal was orthorhombic and belonged to space group C222(1).