2-hydroxyhexa-2,4-dienoate hydratase (, tesE (gene), hsaE (gene)) is an enzyme with systematic name 4-hydroxy-2-oxohexanoate hydro-lyase ((2Z,4Z)-2-hydroxyhexa-2,4-dienoate-forming). This enzyme catalyses the following chemical reaction
This enzyme catalyses a late step in the bacterial steroid degradation pathway.