Haloalkane dehalogenases are found in certain bacteria and belong the alpha-beta hydrolase fold superfamily of enzymes.

An analysis of the sequences and structures of haloalkane dehalogenase and their homologues divided the family into three subfamilies, which differ mainly in the composition of their catalytic pentad and cap domain.

This will deprotonate water, form a tetrahedral intermediate at the original ester, and create an imidazolium cation at histidine.

These residues provide hydrogen bond donor groups to the chloride as it begins to undergo the SN2 reaction and become an anion.

A number of halogenated compounds are environmentally toxic industrial by-products, and it has been suggested that haloalkane dehalogenases may be useful catalysts for their biodegradation, with potential applications in bioremediation.