Hydrolyzes N(G),N(G)-dimethyl-L-arginine (ADMA) and N(G)-monomethyl-L-arginine (MMA) which act as inhibitors of NOS. Has therefore a role in the regulation of nitric oxide generation. H2O + N(omega),N(omega)-dimethyl-L-arginine = dimethylamine + L-citrulline Inhibited by zinc ions. Monomer. Detected in red blood cells (at protein level). Widely distributed, high amounts found in kidney, brain, aorta and pancreas. Belongs to the DDAH family.