[Selection of optimal conditions for measuring aspartate aminotransferase activity]

Various systems for estimation of aspartate aminotransferase activity were compare with regard to national and international recommendations. An increase of 1-aspartate concentration from 33 mM/1 to 200 mM/1 and of alpha-ketoglutarate from 6.7 mM/1 to 12 mM/1 elevated the enzymatic activity by 30-40%. Addition of pyridoxal phosphate into reaction mixture caused a decrease in the activation from 33% to 7.3%, respectively. The ratio of activation varied from 9.9% to 53.3% in the optimal test using blood serum from patients and phosphate buffer. Thus, one of requirements on evaluation of maximal aspartate aminotransferase activity and on production of reproducible results is application of optimal concentrations of reagents with addition of pyridoxal phosphate into reaction mixture.