Inhibition of rat hepatic microsomal styrene oxide hydration by mercury and zinc in vitro.

1. Mercury and zinc inhibited the hydration of styrene oxide in rat hepatic microsomal preparation in vitro. The apparent Ki values for the inhibition, were about 250 microM. 2. The inhibition was non-competitive. The data are consistent with the earlier observation that inhibition of styrene oxide hydration by cadmium in microsomal preparations is non-competitive. 3. The kinetics indicate that the metals are bound to a site different from the active centre of the enzyme.