Catalyzes the deimination of arginine residues of proteins (By similarity). In oocytes, is released during cortical reaction and plays a role in preimplantation cleavage and early embryonic development (PubMed:16137333). May be involved in cytoskeletal reorganization in the egg and early embryo (PubMed:17587491). H2O + L-arginyl-[protein] = L-citrullyl-[protein] + NH4(+) Predominantly cytoplasmic (oocyte cytoplasmic sheets), also nuclear. Released extracellularly during the cortical reaction, and remains associated with the blastomeres surfaces as a peripheral membrane protein until the blastocyst stage of development (PubMed:16137333). Expressed at very high levels in oocytes. Weakly expressed in testis. Expressed in primordial, primary, secondary and Graafian follicles, and in immature oocytes, mature eggs and blastocyst (at protein level). Detected in developing oocytes and early embryo. Detected in immature-germinal vesicle-stage oocytes, mature metaphase II arrested eggs and pronuclear zygotes, 2-cell, 4-cell and morula stages. Expression decreases in blastocyst stage. Phosphorylation at Ser-2, possibly by RSK-type kinases, and Ser-434 creates binding sites for 14-3-3 proteins. Knockout aninmals are viable and present at the expected Mendelian ratio. They do not exhibit any overt abnormalities. Female mice exhibit dispersal of the cytoskeletal sheets in oocytes that lead to a failure of zygotes to progress beyond the 2-cell stage and infertility (PubMed:17587491). Male fertility is not affected (PubMed:17587491). Belongs to the protein arginine deiminase family.