Leukotriene-B4 20-monooxygenase () is an enzyme that catalyzes the chemical reaction
The four substrates of this enzyme are leukotriene B4, reduced nicotinamide adenine dinucleotide phosphate (NADPH), oxygen and a proton. Its products are 20-hydroxy-leukotriene B4, oxidised NADP<sup>+</sup>, and water.
This enzyme is a cytochrome P450 omega hydroxylase that uses molecular oxygen as oxidant and incorporates one of its atoms into the starting material. The systematic name of this enzyme class is (6Z,8E,10E,14Z)-(5S,12R)-5,12-dihydroxyicosa-6,8,10,14-tetraenoate,N ADPH:oxygen oxidoreductase (20-hydroxylating). Other names in common use include leukotriene-B4 20-hydroxylase, leucotriene-B4 omega-hydroxylase, LTB4 20-hydroxylase, and LTB4 omega-hydroxylase. It participates in arachidonic acid metabolism and contains heme.