2-hydroxycyclohexanone 2-monooxygenase () is an enzyme that catalyzes the chemical reaction
The four substrates of this enzyme are 2-hydroxycyclohexan-1-one, reduced nicotinamide adenine dinucleotide phosphate (NADPH), oxygen, and a proton. Its products are 6-hydroxyhexano-6-lactone, oxidised NADP<sup>+</sup>, and water.
This enzyme is an oxidoreductase, acting on paired donors, with molecular oxygen as oxidant and incorporating one of its atoms. The systematic name of this enzyme class is 2-hydroxycyclohexan-1-one,NADPH:oxygen 2-oxidoreductase (1,2-lactonizing). The product spontaneously forms 6-oxohexanoic acid and in Acinetobacter this can be further oxidised to adipic acid.