preferred_name: protoporphyrin IX + 3 AH2 => protoporphyrinogen IX + 3 A
preferred_name_lc: protoporphyrin ix + 3 ah2 => protoporphyrinogen ix + 3 a
label: protoporphyrin IX + 3 AH2 => protoporphyrinogen IX + 3 A
label_lc: protoporphyrin ix + 3 ah2 => protoporphyrinogen ix + 3 a