Lignostilbene alphabeta-dioxygenase () is an enzyme that catalyzes the chemical reaction
The two substrates of this enzyme are 3,3'-dimethoxy-trans-stilbene-4,4'-diol and oxygen. Its product is two equivalents of vanillin. The enzyme from Pseudomonas species cleaves the ethylene bond in a general class of natural lignin derivatives called lignostilbenes.
This enzyme belongs to the family of oxidoreductases, specifically those acting on single donors with O<sub>2</sub> as oxidant and incorporation of two atoms of oxygen into the substrate (oxygenases). The oxygen incorporated need not be derived from O<sub>2</sub>. The systematic name of this enzyme class is 1,2-bis(4-hydroxy-3-methoxyphenyl)ethylene:oxygen oxidoreductase (alphabeta-bond-cleaving). It employs one cofactor, iron.