Deiminates the guanidino group of C-terminal arginine residues on a variety of peptides, including the vasoregulatory peptide-hormone bradykinin, to yield ammonia and a citrulline residue. May promote the growth of the pathogen in the periodontal pocket by producing ammonia, ammonia having a protective effect during acidic cleaning cycles in the mouth. Inhibited by cysteine and TLCK. Inhibited by high concentration of thiourea and thio-L-citrulline. Optimum pH is 9.3. Belongs to the agmatine deiminase family.