pteridine-2,4,6,7-tetrol <=> xanthine-8-carboxylate + H(+)
pteridine-2,4,6,7-tetrol <=> xanthine-8-carboxylate + h(+)
pteridine-2,4,6,7-tetrol <=> xanthine-8-carboxylate + H(+)
pteridine-2,4,6,7-tetrol <=> xanthine-8-carboxylate + h(+)