Biphenyl 2,3-dioxygenase () is an enzyme that catalyzes the chemical reaction
The four substrates of this enzyme are biphenyl, reduced nicotinamide adenine dinucleotide (NADH), oxygen, and a proton. Its products are (1S,2R)-3-phenylcyclohexa-3,5-diene-1,2-diol and oxidised NAD<sup>+</sup>.
This enzyme is an oxidoreductase that uses molecular oxygen as oxidant and incorporates both its atoms into the starting material. The systematic name of this enzyme class is biphenyl,NADH:oxygen oxidoreductase (2,3-hydroxylating). It is also called biphenyl dioxygenase. It is a Rieske protein containing an ironâÂÂsulfur cluster and participates in biphenyl degradation.
As of late 2007, two structures have been solved for this class of enzymes, with PDB accession codes and .