In enzymology, a protein-arginine deiminase (EC 3.5.3.15) is an enzyme that catalyzes a form of post translational modification called arginine de-imination or citrullination:
protein -arginine + H2O formula_1 protein -citrulline + NH3
Thus, the two substrates of this enzyme are protein -arginine (arginine residue inside a protein) and H2O, whereas its two products are protein -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 1WD8, 1WD9, 1WDA, 2DEW, 2DEX, 2DEY, and 2DW5.
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.
References.
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