Limonene 1,2 epoxide hydrolase

In enzymology, a limonene-1,2-epoxide hydrolase (EC 3.3.2.8) is an enzyme that catalyzes the chemical reaction

Thus, the two substrates of this enzyme are limonene-1,2-epoxide and H₂O, whereas its product is limonene-1,2-diol.

This enzyme belongs to the family of hydrolases, specifically those acting on ether bonds (ether hydrolases). The systematic name of this enzyme class is limonene-1,2-epoxide hydrolase. This enzyme is also called limonene oxide hydrolase. This enzyme participates in limonene and pinene degradation.

Epoxide hydrolases catalyse the hydrolysis of epoxides to corresponding diols, which is important in detoxification, synthesis of signal molecules, or metabolism. Limonene-1,2- epoxide hydrolase (LEH) differs from many other epoxide hydrolases in its structure and its novel one-step catalytic mechanism. Its main fold consists of a six-stranded mixed beta-sheet, with three N-terminal alpha helices packed to one side to create a pocket that extends into the protein core. A fourth helix lies in such a way that it acts as a rim to this pocket. Although mainly lined by hydrophobic residues, this pocket features a cluster of polar groups that lie at its deepest point and constitute the enzymes active site.