Protein Domain : Protein-arginine deiminase, C-terminal IPR013530

Type	Domain
Description	In the presence of calcium ions, Protein-arginine deiminase (PAD) enzymes catalyse the post-translational modification reaction responsible for the formation of citrulline residues from protein-bound arginine residues []. Four PAD isotypes of PAD have been identified in mammals, a fifth may also exist. Non-mammalian vertebrates appear to have only a single PAD enzyme. All known natural substrates of PAD are proteins known to have an important structural function, such as keratin (PAD1), intermediate filaments or proteins associated with intermediate filaments. Citrulination may have consequences for the structural integrity and interactions of these proteins. Physiological levels of calcium appear to be too low to activate these enzymes suggesting a role between PAD activation and loss of calcium homeostasis during terminal differentiation and cell death (apoptosis). In humans, PAD enzymes may be involved in cytoskeletal reorganization in the egg and early embryo [ ]. These enzymes abolish the methyltransferase activity of Nicotinamide- N-methyltransferase (NNMT) through its citrullination, which may play a role in a subset of breast cancers and several chronic disease conditions [, ].
Short Name	PAD_C