preferred_name: histidine => urocanate + NH4+ (Caenorhabditis elegans)
preferred_name_lc: histidine => urocanate + nh4+ (caenorhabditis elegans)
label: histidine => urocanate + NH4+ (Caenorhabditis elegans)
label_lc: histidine => urocanate + nh4+ (caenorhabditis elegans)