Mechanism of extradiol aromatic ring-cleaving dioxygenases.

The extradiol aromatic ring-cleaving dioxygenases activate molecular oxygen by binding both O(2) and the catecholic substrate to a reduced active site metal, generally Fe(II). Progress has been made in understanding the mechanism of this reaction through the combined use of kinetic, computational, biomimetic, structural, and diagnostic chemical approaches. It appears that O(2) is activated by accepting an electron transferred from the substrate through the metal, thereby simultaneously activating oxygen and substrate for reaction with each other.