Reaction catalyzed by type I protein arginine methyltransferase (2.1.1.319)

2		+			=	2		+
	2 S-adenosyl-L-methionine	+		[protein]-L-arginine	=		2 S-adenosyl-L-homocysteine	+		[protein]-Nomega,Nomega-dimethyl-L-arginine