Nitrilase/cyanide hydratase and apolipoprotein N-acyltransferase <p>This family contains nitrilases that break carbon-nitrogen bonds and appear to be involved in the reduction of organic nitrogen compounds and ammonia production [<cite idref="PUB00005733"/>]. They all have distinct substrate specificity and include cyanide hydratases, aliphatic amidases, beta-alanine synthase, and a few other proteins with unknown molecular function. Sequence conservation over the entire length, as well as the similarity in the reactions catalyzed by the known enzymes in this family, points to a common catalytic mechanism. They have an invariant cysteine that is part of the catalytic site in nitrilases. Another highly conserved motif includes an invariant glutamic acid that might also be involved in catalysis [<cite idref="PUB00005733"/>].</p>