preferred_name: histidine => urocanate + NH4+ (Dictyostelium discoideum)
preferred_name_lc: histidine => urocanate + nh4+ (dictyostelium discoideum)
label: histidine => urocanate + NH4+ (Dictyostelium discoideum)
label_lc: histidine => urocanate + nh4+ (dictyostelium discoideum)