Mitochondrial aspartate aminotransferase by immunoprecipitation method in patients with acute myocardial infarction.

The semiautomated kinetic procedure for determining cytoplasmic aspartate aminotransferase (c-AST) and mitochondrial aspartate aminotransferase (m-AST) activities was studied by the use of the immunoprecipitation method with anti-c-AST antibody in serum samples. The measured activity for m-AST remained constant after the addition of c-AST up to 1,000 IU/l throughout the 60-min incubation period. The measurements of m-AST activity were reproducible, selective and complete as determined by a purified m-AST. The precision of this method was as good as that of the manual method (CV 2.04%). The present method and the manual method gave approximately equal results for m-AST (r = 0.987). The effects of activations on m- and c-AST activity were compared by the addition of pyridoxal 5'-phosphate to sera of various diseases. A higher activation ratio by pyridoxal 5'-phosphate was observed on both aspartate aminotransferase activities in the serum of patients with ischemic heart diseases than in the serum of patients with liver diseases.