TABLE 1.

Steady-state kinetic parameters of BphK for chlorinated HOPDAs and GSHa

HOPDAKm GSH (μM)Km ClH (μM)kcat (s−1)kcat/Km ClH (103 M−1 s−1)kcat/Km GSH (103 M−1 s−1)
3-Cl110 (20)17 (5)0.16 (0.008)10 (2)1.5 (0.3)
5-Cl370 (190)110 (40)0.24 (0.06)2 (1)0.6 (0.3)
3,9,11-triCl390 (120)10 (3)0.010 (0.001)1.0 (0.2)0.03 (0.01)
  • a Values in parentheses represent standard errors. The kinetic parameters for 5-Cl HOPDA have higher standard errors as the enzyme could not be saturated with its substrates. Experiments were performed using potassium phosphate, pH 6.5 (I = 0.05 M), at 25°C.