Kinetic Properties of Soil Urease Inhibited by Allicin and NBPT (N-(n-butyl) thiophosphoric triamide)

The kinetic properties of soil urease inhibited by allicin was investigated. Substrate at different concentrations (400, 800, 1200, 1600 and 2000 mu g urea-N/g soil) were examined with and without allicin and concurrently compared with N-(n-butyl) thiophosphoric triamide (NBPT). The difference between the amount of urea added and that recovered after incubation for 5h was taken as an estimate of urease activity. The amount of urea remained in soil was quantified using diacetylmonoxime (DAM) calorimetric method. Both of the inhibitors, allicin and NBPT, increased Km by 26% and 30%, respectively, compared to control. Whereas, for V-max, were decreased by 21% for allicin and by 12% for NBPT. The Lineweaver-Burk plot shows allicin and NBPT worked as mixed type inhibitors. Besides, it shows the catalytic capacity (K-m/V-max) of inhibitor treated samples reduced by 40%. The deviation between the kinetic parameters of these two inhibitors (allicin and NBPT) found to be less than 10% and thus makes allicin to be a promising candidate as bioinhibitor for agriculture field.