Leukotriene A4 hydrolase, also known as LTA4H is a human gene. The protein encoded by this gene is a bifunctional enzyme (EC 3.3.2.6) which converts leukotriene A4 to leukotriene B4 and acts as an aminopeptidase. This enzyme belongs to the family of hydrolases, specifically those acting on ether bonds (ether hydrolases). The systematic name of this enzyme class is (7E,9E,11Z,14Z)- (5S,6S)-5,6-epoxyicosa-7,9,11,14-tetraenoate hydrolase. Other names in common use include LTA4 hydrolase, LTA4H, and leukotriene A4 hydrolase. This enzyme participates in arachidonic acid metabolism. The hydrolase activity is used in the final step of the biosynthesis of leukotriene B4, a proinflammatory mediator. The aminopeptidase activity has been shown to degrade proline-glycine-proline (PGP), a neutrophil chemoattractant and biomarker for chronic obstructive pulmonary disease (COPD). Several transcript variants encoding different isoforms have been found for this gene.