Based on limited published evidence, FAHD2B is a mitochondrial tautomerase that converts enol-oxaloacetate to its physiological keto form of oxaloacetate 1. This enzymatic activity prevents succinate dehydrogenase inhibition, thereby maximizing aerobic respiration efficiency 1. FAHD2B belongs to the fumarylacetoacetate hydrolase domain-containing protein family, whose members carry out diverse enzymatic reactions 2. The protein localizes to mitochondria and participates in oxaloacetate metabolism through its tautomerase activity.