Protein arginine deiminases (PADs) are guanidino-modifying enzymes belonging to the amidinotransferase superfamily and are designated PAD1-4 and PAD6. All enzymes are cytosolic except for PAD4 which is localized in the nucleus.1 PAD4 is a homodimer that functions as a transcriptional coregulator to catalyze the conversion of specific arginine residues to citrulline in a calcium-dependent manner. PAD4 substrates include histones H2A, H3, and H4, whose post-translational modifications play a large role in gene regulation.2 Benzoylated arginine substrates like N--benzoyl-L-arginine ethyl ester (BAEE) have proven to be useful tools for characterization of PAD4, having similar kinetic properties to the natural substrates.3 PAD4 itself can undergo autocitrullination at several sites, which inhibits its enzymatic activity and may play an important role in regulating citrullination in cells.4 PAD4 activity is incrEAsed in rheumatoid arthritis, producing an abundance of citrulline-containing proteins that can be recognized by autoantibodies, which cause the immune system to attack its own tissues.5 PAD4 has also been implicated in several other disEAses including multiple sclerosis, Alzheimers disEAse, glaucoma, and cancer.2 Caymans PAD4 (human recombinant; His- and GST-tagged) protein contains two types of affinity tags, His and GST, that allow for flexibility in the removal of PAD4 following citrullination rEActions and an enterokinase clEAvage site that facilitates removal of both the His and GST tags.Technical InformationSynonymsPADI4PADI5PDI5Peptidylarginine Deiminase 4Protein Arginine Deiminase 4Purity85% estimated by SDS-PAGESourceActive recombinant N-terminal hexahistidine- and GST-tagged protein expressed in E. coliAmino Acids2-663MW103.2 kDaFormulation50 mM HEPES, pH 8.0, 300 mM sodium chloride, 1mM DTT, and 10% glycerolSpecific Activitybatch specificUniProt Accession Q9UM07