Intradiol dioxygenase supgroup. Intradiol dioxygenases catalyze the critical ring-cleavage step in the conversion of catecholate derivatives to citric acid cycle intermediates. They break the catechol C1-C2 bond and utilize Fe3+, as opposed to the extradiol-cleaving enzymes which break the C2-C3 or C1-C6 bond and utilize Fe2+ and Mn+. The family contains catechol 1,2-dioxygenases and protocatechuate 3,4-dioxygenases. The specific function of this subgroup is unknown.
Jiyao W et al.(2023). "The conserved domain database in 2023.",