In enzymology, a protein-arginine deiminase is an enzyme that catalyzes a form of post translational modification called arginine de-imination or citrullination: Thus, the two substrates of this enzyme are protein L -arginine (arginine residue inside a protein) and H2O, whereas its two products are protein L -citrulline and NH3: This enzyme belongs to the family of hydrolases, those acting on carbon-nitrogen bonds other than peptide bonds, specifically in linear amidines. The systematic name of this enzyme class is protein-L-arginine iminohydrolase. This enzyme is also called peptidylarginine deiminase.

Structural studies

As of late 2007, seven structures have been solved for this class of enzymes, with PDB accession codes, , , , , , and.

Mammalian proteins

Mammals have 5 protein-arginine deiminases, with symbols except for rodents, there the letter case is different: The different case is just a historical artifact. It doesn't indicate that the rodent proteins are special.