抄録
We developed a rapid enzymatic method forthe measurement of plasma branched chain amino acids based on the following principle. The branched chain amino acids are converted to a-ketoacids by a leucine dehydrogenase coupling the reduction of NAD. NADH converts 3-(4, 5-dimethy1-2-thiagolyl)-2, 5-diphenyl-2H tetrazolium bromide to formazan which is measured, with the catalyst of 1-methoxy-5-methylphenazium methylsulfate. The method allowed measurement of the branched chain amino acids in the visible range. In addition, application to various automated analysis system was possible. The impression of the reproducibility was 2% or less and the measurement was not affected by other amino acids. The obtained values correlated well with those of amino acid analysis by HPLC (y=0.967x+9.75, r=0.981), showing excellent precision of the method.
