In enzymology, a Watasenia-luciferin 2-monooxygenase (EC 1.13.12.8) is an enzyme that catalyzes the chemical reaction Watasenia luciferin + O2 rightleftharpoons oxidized Watasenia luciferin + CO2 + hnu .Thus, the two substrates of this enzyme are Watasenia luciferin and O2, whereas its 3 products are oxidized Watasenia luciferin, CO2, and hn.This enzyme belongs to the family of oxidoreductases, specifically those acting on single donors with O2 as oxidant and incorporation of two atoms of oxygen into the substrate (oxygenases). The oxygen incorporated need not be derived from O with incorporation of one atom of oxygen (internal monooxygenases o internal mixed-function oxidases). The systematic name of this enzyme class is Watasenia-luciferin:oxygen 2-oxidoreductase (decarboxylating). This enzyme is also called Watasenia-type luciferase.