L-Lactate oxidase (LOX) FMN-binding domain. LOX is a member of the family of FMN-containing alpha-hydroxyacid oxidases and catalyzes the oxidation of l-lactate using molecular oxygen to generate pyruvate and H2O2. This family occurs in both prokaryotes and eukaryotes. Members of this family include flavocytochrome b2 (FCB2), glycolate oxidase (GOX), lactate monooxygenase (LMO), mandelate dehydrogenase (MDH), and long chain hydroxyacid oxidase (LCHAO).