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 skeletal muscle, lung, heart and brain (at protein level). Detected in liver, kidney and lung. Death at embryonic stages. Heterozygous mice show no visible phenotype, but have higher than normal tissue and plasma levels of asymmetric dimethylarginine (ADMA). They have increased mean arterial blood pressure and systemic vascular resistance, and decreased cardiac output and heart rate, probably due to reduced levels of nitric oxide (NO). Belongs to the DDAH family.