Preparation and characterization of Ng-mono-, di- and trimethylated arginines.

A simple procedure is described for the synthesis of N-guanidino methylated ariginines. The yields of all methylarginines exceed those obtained by earlier procedures. Trimethylarginine - an amino acid not found in natural sources - has also been synthesized with this technique. Studies with arginine specific dicarbonyl reagents showed that methylation of guanidino-groups decreases the reactivity of methyl-arginines, only monomethylarginine reacting at a rate comparable to that of arginine.