Iron/ascorbate-dependent oxidoreductase: part of the gene cluster that mediates the biosynthesis of domoic acid (DA) and derivatives, natural products with neurochemical activity acting as ionotropic glutamate receptor (iGluR) agonists, thus being neurotoxins causing amnesic shellfish poisoning (ASP) (PubMed:30262498). Catalyzes the conversion of 7'-N-carboxy-L-geranyl-L-glutamic acid (cNGG) to isodomoic acid-A (PubMed:30262498). Mediates also the conversion of N-geranyl-L-glutamic acid (L-NGG) to dainic acid A (PubMed:30262498). 2-oxoglutarate + N-(7'-carboxy-7'-demethylgeranyl)-L-glutamate + O2 = CO2 + H2O + isodomoate A + succinate 2-oxoglutarate + N-geranyl-L-glutamate + O2 = CO2 + dainate A + H2O + succinate Binds 1 Fe(2+) ion per subunit. Secondary metabolite biosynthesis. Up-regulated under phosphate limitation and by increasing partial pressure of CO(2). Belongs to the iron/ascorbate-dependent oxidoreductase family.