Fig. 7From: Andrographolide sodium bisulphite-induced inactivation of urease: inhibitory potency, kinetics and mechanisma Thiol influence on urease inactivation by ASB relative to the control activity. The percent of the enzyme activity in the presence of ASB without the thiol is given as comparison. Concentration of the thiol: L-cys, DTT, and ASB were 4Â mM. Enzyme activity was determined after 10, 30, 60Â min of incubation; b Influence of thiol order of components preincubation on urease inactivation by ASB. The initial 20Â min preincubation mixture contained components given in brackets. The preincubation was continued the further 20Â min after addition of the last component (component given outside for brackets). The final preincubation mixtures contained 0.25Â mg/mL urease, 20Â mM phosphate buffer, pHÂ 7.0, 2Â mM EDTA, 4Â mM ASB, and DTT or L-cys. Enzyme activity was determined after 40Â min of preincubation time. The percent of the enzyme activity in the presence of ASB without the thiol is given for comparisonBack to article page