A rapid chromatographic method for the determination of omega-N-methylarginines in protein and muscle tissues

A rapid and sensitive chromatographic method is described for the complete separation and determination of NG-methylarginine, NG,NG-dimethlarginine, NG,N'G-dimethylarginine, and related compounds in protein and muscle tissue hydrolysates. This method is designed to be used both with conventional amino acid analyzers using a single column (10 X 0.9 cm) of Durrum type DC-6A resin at 51 degrees C, one buffer system (0.21 M sodium citrate pH 5.40), and one buffer flow rate (70 ml/h) and with the accelerated and fully automatic Beckman Spinco model 121M amino acid analyzer using a 10 X 0.28 cm microcolumn packed with the Beckman type AA-10 resin and operated with the same buffer at 7.9 ml/h. This procedure was successfully applied to the determination of omega-N-methylarginines in various animal tissues, and the presence of four as yet unidentified ninhydrin-positive compounds is reported.