N(G),N(G)-dimethylarginine dimethylaminohydrolases 1 and 2 (DDAH1 and 2) play a role in the regulation of nitric oxide generation. They can hydrolyse an endogenous inhibitor of nitric oxide synthase (NOS), N(omega),N(omega)-dimethyl-L-arginine (ADMA) to dimethylamine (DMA) and L-citrulline (L-Cit) (Forbes et al. 2008, Wang et al. 2009, Cillero-Pastor et al. 2012).