Epoxide hydrolases From our end, the epoxide hydrolase story started with an EU network that is officially finished, but has continued in two major collaborations. With Michael Arand of the Institute of Toxicology, University of Mainz, Germany, we solved the structure of an epoxide hydrolase from Aspergillus niger . This enyzme is representative of a family including the microsomal epoxide hydrolase that is most important for detoxification of epoxides in the mammalian liver. The structure is an alpha-beta hydrolase fold, as shown here . The active site contains a nucleophilic aspartate acid residue and an Asp-His charge relay, as well as two tyrosine residues that assist epoxide ring opening.
Steric considerations suggest why one enatiomer is strongly preferred.
Limonene epoxide hydrolase from Rhodococcus erythropolis is being worked on with Jan de Bont, previously at Wageningen in the Netherlands. The role of this enzyme in the bacterial system is metabolic, rather than being involved in detoxification. It represents a completely different structural class from the Aspergillus enzyme. The reaction is simple acid catalysis, and so does not require an enzyme-substrate intermediate. Cellulases Alwyn Jones and Jerry Stahlberg have long made Uppsala known for structures of cellulases.