A simple chromatographic method for the determination of the methylated basic amino acids in proteins

A chromatographic method is described for the determination of epsilon-N-monomethyl-epsilon-N, epsilon-N-dimethyl-, and epsilon-N, epsilon-N, epsilon-N-trimethyllysines, 1-methyl-, and 3-methylhistidines, N-G, N-G-dimethyl-, and N-G, N'G-dimethylarginines, ornithine, the diastereoisomers of hydroxylysine, basic amino acids and related compounds, using Durrum type DC-6A 11.0 plus or minus 1.0 mum spherical resin. The complete separation of all of these amino acids as discrete peaks in the Beckman 120B amino acid analyzer was achieved for the first time using a single column (60 times 0.9 cm), one buffer system (0.35 N sodium citrate) adjusted at either pH 5.734 or 5.657 plus or minus 0.002, one buffer flow rate (30 ml/h), and one temperature (28 degrees C). This procedure was used for the analysis of these unusual amino acids in protein hydrolysates of histones and collagen and be applied to the determination of these compounds in hydrolysates of plant and animal tissues.