Urease enzyme and its kinetic and thermodynamic parameters in clay loam soil

Abstract

In the present work, urease enzyme activity of clay loam soil (pH 7.1, organic matter 2.26%, C/N ratio 16), kinetic (V-max, V-m and V-max/K-m) values and thermodynamic (E-a, Delta H, Delta S, and Delta G) parameters of this enzyme is determined. For this purpose, kinetic and thermodynanic parameters are calculated by determining urease activity in soil in different substrate concentrations (0, 1, 2, 4, 6, 8, 10 and 12%), incubation periods (0, 1, 2, 3, 4, 5 and 6 h) and incubation temp. (0, 10, 20, 30, 40 and 50 degrees C). From the results, it is determined, that the speed of reaction starts to become static, while substrate concentration reaches to 8% level and, becomes static at 10% level and the highest speed of reaction in substrate concentration occurs at incubation temperature of 500 degrees C. The highest V-max, V-m and V-max/K-m values are determined at 40 and 50 degrees C and the highest E-a, Delta H and Delta S values are determined in substrate concentration of 10%. It was also determined that Delta G varies between 1.870-2.145 in all substrate concentrations depending on temperature.