Reactions include hydroxylation, desaturation, epoxidation, or multistep demethylation and C-C bond breaks. They are distinguished by being able to react at substrate sites consisting of unactivated saturated hydrocarbon. The geometry of the enzyme substrate complex detemines to site of reaction, not the chemistry of the substrate. Dioxygenases use both atoms of a single molecule of O 2 and typically attack aromatic ring substrates. Ring cleavage is a common outcome.
Allylic radicals are susceptible to attack by molecular oxygen.
Multiple allylic groupings in arachidonate reacting with two moles of O 2 give PGH 2, common prostaglandin precursor. CoA is eliminated, allowing the reduction of carboxylate to aldehyde.