Fig. 1.
Urea cycle and dimethylarginine metabolic pathways. a l-Arginine is the common substrate of arginase and nitric oxide synthase (NOS). Asymmetric dimethylarginine (ADMA) and l-NG-monomethyl arginine (MMA) are potent inhibitors of NOS, whereas symmetric dimethylarginine (SDMA) inhibits nitric oxide (NO) production by inhibiting l-arginine cellular uptake. b Schematic diagram showing the pathways that produce methylated arginines (MMA, ADMA, and SDMA). PRMT Protein arginine methyltransferase