Table 2.

Steady-state kinetic parameters of the thiol substrate and metal-ion selectivity of FosB

Thiol substrateMetal ionkcat(s−1)kcat/Kmthiol (M−1s−1)Kmthiol (mM)
l-CysMg2+6.3 ± 0.3180 ± 2035 ± 3
GSHMg2+0.027 ± 0.0021.8 ± 0.215 ± 2
CoASHMg2+a0.40 ± 0.03 >50
l-CysNi2+7.8 ± 0.5190 ± 3041 ± 3
GSHNi2+0.066 ± 0.0059.1 ± 1.77 ± 1
l-CysMn2+a6.9 ± 0.2>200
GSHMn2+a0.093 ± 0.001 >50
CoASHMn2+a0.0009 ± 0.0001>100
  • a A linear dependence on the thiol substrate concentration was observed, precluding a determination ofkcat. Therefore, a conservative lower limit forKmthiol was estimated from the substrate concentration range used.