Catalyses the hydrolysis of trans-substituted epoxides, such as trans-stilbene oxide, as well as various aliphatic epoxides derived from fatty-acid metabolism . It is involved in the metabolism of arachidonic epoxides (epoxyicosatrienoic acids; EETs) and linoleic acid epoxides. The EETs, which are endogenous chemical mediators, act at the vascular, renal and cardiac levels to regulate blood pressure [4,5]. The enzyme from mammals is a bifunctional enzyme: the C-terminal domain exhibits epoxide-hydrolase activity and the N-terminal domain has the activity of EC 184.108.40.206, lipid-phosphate phosphatase [1,2]. Like EC 220.127.116.11, microsomal epoxide hydrolase, it is probable that the reaction involves the formation of an hydroxyalkyl---enzyme intermediate [4,6]. The enzyme can also use leukotriene A4, the substrate of EC 18.104.22.168, leukotriene-A4 hydrolase, but it forms 5,6-dihydroxy-7,9,11,14-icosatetraenoic acid rather than leukotriene B4 as the product [9,10]. In vertebrates, five epoxide-hydrolase enzymes have been identified to date: EC 22.214.171.124 (leukotriene-A4 hydrolase), EC 126.96.36.199 (hepoxilin-epoxide hydrolase), EC 188.8.131.52 (microsomal epoxide hydrolase), EC 184.108.40.206 (soluble epoxide hydrolase) and EC 220.127.116.11 (cholesterol 5,6-oxide hydrolase) .
EC 18.104.22.168 created 2006 (EC 22.214.171.124 created 1978, part incorporated 2006)