Figure 4.

Kinetic analysis of CysA2 using thiosulfate, 3-mercaptopyruvate and cyanide as co-substrates. The thiosulfate:cyanide sulfurtanserase activity or mercaptopyruvate:cyanide sulfurtanserase activity of the enzyme CysA2 was evaluated via a modification of the Sorbo method⁸⁸. The reaction mixture consisted of 100 mM Tris-HCl, pH 8.0, 50 mM thiosulfate or 50 mM Mercaptopyravate, in a total volume of 600 μL. The mixture was preincubated at 37 °C for 10 minutes, and the reaction was started by the addition of 50 mM KCN the absorbance of the supernatant was measured at 460 nm. One unit of sulfurtransferase activity was defined as 1 nmol of SCN- formed every minute. (a) Enzimatic cinetic to thiosulfate. Km of 2.97 mM +/− 0.05 (SEM) and Vmax of 7.40 U/mg +/− 0.72 U/mg (SEM). Error Bar = Standard deviation of the mean (SEM). (b) Linearization by Hanes-Equation to enzymatic assay to thiosulfate substrate. (c) Enzymic kinetics to KCN, Km of 1.66 mM +/− 0.05 (SEM) for reaction thiosulphate. Error Bar = Standard deviation of the mean (SEM). (d) Linearization by Hanes-Equation to enzymatic assay to cyanide substrate. (e) Enzimatic cinetic to Mercaptopyruvate. Km of 7.02 mM +/− 0.05 (SEM) and Vmax of 0.0461 U/mg +/− 0.0012 U/mg (SEM). Error Bar = Standard deviation of the mean (SEM). (f) Linearization by Hanes-Equation to enzymatic assay to mercaptopyruvate substrate. (g) Enzymic kinetics to KCN. 9.11 mM +/− 0.05 (SEM) for reaction 3-mercaptopyruvate. Error Bar = Standard deviation of the mean (SEM). (h) Linearization by Hanes-Equation to enzymatic assay to cyanide substrate.