[Effect of temperature on kinetic of soil urease inhibited by Hg]

Urease kinetics inhibited by Hg in two meadow burozem, fertilized by different ways and two phaeozem soils with different organic matter content was investigated at different temperatures. The results showed that the urease activity and kinetic parameter V(max) and V(max)/K(m) were higher in soils with high organic matter content than that in soils with low organic matter among the same soil type. It indicated that organic matter had great adsorption capacity to urease. Soil urease V(max) and V(max)/K(m) in phaeozem were generally higher than that in meadow organic matter had great adsorption capacity to urease. Soil urease V(max) and V(max)/K(m) in phaeozem were generally higher than that in meadow burozem, but urease activity and K(m) were not comparable among different soil types. K(m) depended on not only the organic matter content of soils, but also fertilization ways. As incubating temperature increased, urease activity, V(max) and V(max)/K(m) value enhanced under the optical catalysis temperature. Hg behaved as uncompetitive inhibitor to soil urease in this experiment. The negative effect that Hg inhibited urease activity, K(m), V(max) and V(max)/K(m) increased with temperature increasing, indicated that the protective capacity of soil on urease decreased with the temperature increasing.