dioxygenaasi

Dioxygenase is a type of enzyme that catalyzes the incorporation of both atoms of molecular oxygen into a substrate. These enzymes are crucial in various metabolic pathways, particularly in the breakdown of aromatic compounds and the synthesis of important biomolecules. They are classified into two main groups based on their cofactor requirements: iron-containing dioxygenases and flavin-containing dioxygenases.

Iron-containing dioxygenases often utilize a non-heme iron center to activate molecular oxygen, which then reacts with the substrate. Examples include 2-oxoglutarate dioxygenases, involved in collagen biosynthesis, and Rieske dioxygenases, known for their role in the degradation of environmental pollutants like aromatic hydrocarbons. These enzymes frequently catalyze the cis-dihydroxylation of aromatic rings, forming catechols, which are more readily metabolized.

Flavin-containing dioxygenases, on the other hand, depend on flavin cofactors such as FAD or FMN. These enzymes can activate oxygen through mechanisms involving the reduced flavin. Examples include isoflavone dioxygenases, which play a role in plant defense mechanisms, and various dioxygenases involved in the biosynthesis of antibiotics and other secondary metabolites. The specific reaction mechanisms and substrate specificities vary widely among different dioxygenase families. Their activity is essential for the detoxification of xenobiotics and the cycling of nutrients in ecosystems.