What is Asymmetric Dimethylarginine?
Asymmetric dimethylarginine is an endogenous competitive inhibitor of nitric oxide synthase, formed when protein arginine methyltransferases methylate arginine residues in nuclear and cytoplasmic proteins and those proteins are subsequently proteolysed. It is metabolised primarily by dimethylarginine dimethylaminohydrolase enzymes (DDAH-1 and -2) and cleared to a lesser extent by renal excretion. Because it competes with L-arginine for the active site of nitric oxide synthase, elevated ADMA impairs endothelial nitric oxide production, reducing vascular relaxation and favouring endothelial dysfunction, vasoconstriction, and platelet aggregation.