This family includes both nitrilases and cyanide hydratase. Nitrilases (<db_xref db="EC" dbkey="3.5.5.1"/>) are enzymes that convert nitriles into theircorresponding acids and ammonia. They are widespread in microbes as well as inplants where they convert indole-3-acetonitrile to the hormone indole-3-acetic acid. A conserved cysteine has been shown [<cite idref="PUB00004812"/>, <cite idref="PUB00002743"/>] to be essential forenzyme activity; it seems to be involved in a nucleophilic attack on thenitrile carbon atom. Cyanide hydratase (<db_xref db="EC" dbkey="4.2.1.66"/>) converts HCN to formamide. In phytopathogenic fungi, it is used to avoid the toxic effect of cyanide released by wounded plants [<cite idref="PUB00000214"/>].