Table 2.
The concentration of six thiocarbamates and other AChE inhibitors giving 50% inhibition of human red cell AChE
| Inhibitor | Parent compound | Sulphoxide | Sulphone |
|---|---|---|---|
| Molinate | >10 mM | 4.3 mM | 0.16 mM |
| Butylate | >10 mM | ND | 1.0 mM |
| Cycloate | >10 mM | ND | 0.14 mM |
| Pebulate | >10 mM | ND | 0.01 mM |
| Vernolate | >10 mM | ND | 0.02 mM |
| EPTC | >10 mM (39%) | ND | 0.11 mM |
| Paraoxon | 24 nM | ||
| Eserine | 20 nM |
Human red cell AChE was pre-incubated with a range of concentrations of the inhibitors for 10 min in 0.1 M phosphate buffer pH 7.4 at 37°C and then acetylthiocholine added and the enzyme activity determined. Results show the IC50’s derived by curve fitting the data from at least three separate experiments as described in the Materials and Methods. The value in brackets shows the extent of inhibition seen at 10 mM EPTC as a percentage of control. AChE control activity was 950 ± 68 (3) nmol/min/mg protein. ND: not determined.