Rapid ion-exchange method for the determination of 3-methylhistidine in rat urine and skeletal muscle.

A method for the determination of 3-methylhistidine using an automatic amino acid analyser has been developed. A single column system with lithium buffer (pH 3.950, 0.500 mol/l lithium and 0.067 mol/l citrate) was used for elution. The standard amino acid mixture of basic amino acids and some dipeptides usually present in physiological fluids was analysed for the development of the method. 3-Methylhistidine eluted in 46.7 +/- 0.049 min and the peak area coefficient of variation for the same sample was 1.07%. As 3-methylhistidine is completely resolved from the other basic amino acids and some dipeptides (anserine and carnosine), this method is suitable for the analysis of urine and muscle extracts as well as skeletal muscle protein hydrolysates where this amino acid is present in much lower concentrations than other amino acids.