Indeed, mammalian carboxylation needs ATP and biotin for the CO2 activation, and carboxylation of 2-oxoglutarate by the recombinant tumor mutants of isocitrate dehydrogenase has never been observed, even if the mutants do reduce 2-oxoglutarate to 2-hydroxyglutarate [26]. Here, IDH3A is linked to neoplasm.