Substrate | Km | Vmax | Vmax/Km |
---|---|---|---|
μM | nmol/h | 10−3 l/h | |
S-(1,1,2,2-Tetrafluoroethyl)-l-cysteine1a | 302 ± 3 | 2.3 ± 0.03 | 0.008 |
S-(2-Chloro-1,1,2-trifluoroethyl)-l-cysteine1b | 211 ± 3 | 5.78 ± 0.05 | 0.027 |
S-(2-Bromo-1,1,2-trifluoroethyl)-l-cysteine1c | 179 ± 7 | 13.9 ± 0.4 | 0.078 |
S-(2,2-Dibromo-1,1-difluoroethyl)-l-cysteine1d | 203 ± 22 | 6.2 ± 0.4 | 0.030 |
S-[2-(Fluoromethoxy)-1, 1,3,3,3-pentafluoropropyl]-l-cysteine1e | 241 ± 30 | 3.4 ± 0.3 | 0.014 |
S-(Pentachlorobutadienyl)-l-cysteine2a | 124 ± 19 | 15.6 ± 1.2 | 0.126 |
S-(1,2-Dichlorovinyl)-l-cysteine 2b | 273 ± 47 | 0.75 ± 0.07 | 0.003 |
S-[2-(Fluoromethoxy)-1,3,3,3-tetrafluoro-1-propenyl]-l-cysteine2c 2-a | — | — | — |
The cysteine S-conjugates were incubated with purified porcine kidney NAcT, and product formation and kinetic constants were measured as described in Experimental Procedures. The structures of the cysteine S-conjugates are shown in Fig. 1.
Data are shown as mean ± S.D.; n = 4.
↵2-a No activity detected; <0.1 nmol/h after exposition for 1 month.