Hydrolyzes N(G),N(G)-dimethyl-L-arginine (ADMA) and N(G)-monomethyl-L-arginine (MMA). H2O + N(omega),N(omega)-dimethyl-L-arginine = dimethylamine + L-citrulline Inhibited by zinc ions. Competitively inhibited by lysine. Optimum pH is 7-8.5. Homodimer. Belongs to the DDAH family.