I. V. Kushkevych^1,2, H. L. Antonyak³, M. Bartoš²

¹Institute of Animal Biology, NAAS of Ukraine, Lviv;
²University of Veterinary and Pharmaceutical Sciences of Brno, Czech Republic;
³Ivan Franko National University of Lviv, Ukraine;
e-mail: ivan.kushkevych@gmail.com

The investigation of specific activity of ATP sulfurylase and kinetic properties of the enzyme in cell-free extracts of intestinal bacterial strains Desulfovibrio piger Vib-7 and Desulfomicrobium sp. Rod-9 is presented. The microbiological, biochemical, biophysical and statistical methods were used in the work. The optimal temperature (35 ºC) and pH 8.0-8.5 for enzyme reaction were determined. An analysis of kinetic pro­perties of ATP sulfurylase has been carried out. Initial (instantaneous) reaction velocity (V₀), maximum amount of the product of reaction (P_max), the reaction time (half saturation period, τ) and maximum veloci­ty of the ATP sulfurylase reaction (V_max) have been defined. Michaelis constants (K_m^Sulfate, K_m^ATP, K_m^APS, and K_m^{Pyrophosphate­}) of the enzyme reaction were demonstrated for both D. piger Vib-7 and Desulfomicrobium sp. Rod-9 intestinal bacterial strains.