This is a family of arginine deiminases, <db_xref db="EC" dbkey="3.5.3.6"/>. The aligned region corresponds to the C-terminal of the protein. These enzymes catalyse the conversion of arginine + H2O to citrulline + NH3. Also found in this family is the Streptococcus anti tumor glycoprotein [<cite idref="PUB00007581"/>].