Iron/ascorbate-dependent oxidoreductase: part of the gene cluster that mediates the biosynthesis of kainic acid (KA) and derivatives, natural products with neurochemical activity acting as ionotropic glutamate receptor (iGluR) agonists, thus being neurotoxins (PubMed:30995339). Catalyzes the conversion of prekainic acid to kainic acid and kainic acid lactone (PubMed:30995339). 2-oxoglutarate + O2 + prekainate = CO2 + H2O + kainate + succinate 2-oxoglutarate + H(+) + O2 + prekainate = CO2 + H2O + kainate lactone + succinate Binds 1 Fe(2+) ion per subunit. Inhibited by the iron chelator EDTA. Secondary metabolite biosynthesis. Escherichia coli cells expressing Digenea simplex kabC are successfully converting supplied synthetic prekainic acid into kainic acid, thus providing a less expensive method to produce this molecule for neuro-pharmacological applications. Belongs to the iron/ascorbate-dependent oxidoreductase family.