This family represents the N-terminal region of the eukaryotic epoxide hydrolase protein. Epoxide hydrolases (EC:220.127.116.11) comprise a group of functionally related enzymes that catalyze the addition of water to oxirane compounds (epoxides), thereby usually generating vicinal trans-diols. EHs have been found in all types of living organisms, including mammals, invertebrates, plants, fungi and bacteria. In animals, the major interest in EH is directed towards their detoxification capacity for epoxides since they are important safeguards against the cytotoxic and genotoxic potential of oxirane derivatives that are often reactive electrophiles because of the high tension of the three-membered ring system and the strong polarization of the C--O bonds. This is of significant relevance because epoxides are frequent intermediary metabolites which arise during the biotransformation of foreign compounds. This family is often found in conjunction with pfam00561.