The carbon-nitrogen hydrolase domain is an around 265-residue domain found in
numerous enzymes involved in the reduction of organic nitrogen compounds and
ammonia production. Based on their sequence similarity and on the reactions
they catalyze, these enzymes can be classified into functionally distinct
groups including [1,2]:
Nitrilases (EC 22.214.171.124), which cleave various nitriles into the
corresponding acids and ammonia (see <PDOC00712>).
Cyanide hydratase (EC 126.96.36.199) of pathogenic fungi, which detoxifies HCN
that is released by their hosts, cyanogenic plants, after injury (see
Aliphatic amidases (EC 188.8.131.52), which enable prokaryotes to use acetamides
as both carbon and nitrogen source.
β-alanine synthase (N-carbamoyl-β-alanine amino hydrolase)
(EC 184.108.40.206), which catalyses the last step of pyrimidine catabolism.
AdgA (for ammonia-dependent growth) from Rhodobacter species (EC 220.127.116.11).
It appears to be essential for using various amino acids as nitrogen
Biotinidase (EC 18.104.22.168), which catalyzes the hydrolysis of biocytin to
biotin and lysine.
Pantetheinase (EC 22.214.171.124) (Pantetheine hydrolase) (Vanin), which
hydrolyzes specifically one of the carboamide linkages in D-pantetheine,
thus recycling pantothenic acid (vitamin B5) and releasing cysteamine.
Apolipoprotein N-acyltransferase (EC 2.3.1.-) (gene lnt), a bacterial
enzyme that transfers the fatty acyl group on membrane lipoproteins.
The carbon-nitrogen hydrolase domain can be found alone or associated with
other domains, such as the NAD synthase domain, the HIT histidine triad (see
<PDOC00694>), the acetyltransferase domain or the glycosyltransferase domain.
The carbon-nitrogen hydrolase domain is characterized by several conserved
motifs, one of which contains a cysteines that is part of the catalytic site
in nitrilases. Another highly conserved motif includes a glutamic acid that
might also be involved in catalysis .
The profile we developed covers the entire carbon-nitrogen hydrolase domain.
March 2017 / Profile revised.
PROSITE method (with tools and information) covered by this documentation:
PROSITE is copyright. It is produced by the SIB Swiss Institute
Bioinformatics. There are no restrictions on its use by non-profit
institutions as long as its content is in no way modified. Usage by and
for commercial entities requires a license agreement. For information
about the licensing scheme send an email to
or see: prosite_license.html.