PDBsum structure summary In molecular biology, the glucose-methanol-choline oxidoreductase family (GMC oxidoreductase) is a family of enzymes with oxidoreductase activity. The glucose-methanol-choline (GMC) oxidoreductases are FAD flavoproteins oxidoreductases. [ 1 ] [ 2 ] These enzymes include a variety of proteins; choline dehydrogenase (CHD) EC 1.1.99.1 , methanol oxidase (MOX) EC