Asymmetric Dimethylarginine

**Semantic type:** Amino Acid, Peptide, or Protein

**Definition:** A dimethylated derivative of L-arginine where the two methyl groups are attached to arginine in an asymmetrical configuration. Asymmetric dimethylarginine (ADMA) is a competitive inhibitor of nitric oxide synthase (NOS) that is formed when S-adenosylmethionine protein N-methyltransferases transfer two methyl groups from S-adenosylmethionine to one of the two guanidine nitrogen groups of an arginine residue in a protein. ADMA is released when the protein is degraded and is a substrate for dimethylarginine dimethylaminohydrolase (DDAH). Free ADMA in plasma competes with the L-arginine for binding to the heme in NOS and inhibits nitric oxide (NO) synthesis. Decreased synthesis of NO inhibits vasodilation and leads to endothelial dysfunction. Elevated plasma levels of ADMA are seen in certain types of cancer, cardiovascular disease, hypertension, hyperlipidemia, type 2 diabetes mellitus, and increased oxidative stress.

**Synonyms:** - ADMA - Guanidino-N(1),N(1)-Dimethylarginine - Guanidino-N,N-Dimethylarginine - N(G),N(G)-Dimethylarginine - N(G1),N(G1)-Dimethylarginine - N,N-DIMETHYLARGININE