Chemical control of the mixed function oxidase system and its implications in determining biological hazard

Risk assessment is the process of determining chemical tolerance limits in the environment and can be defined as Z Hazards x L Exposures. Hazard can be factored into two responses to a chemical: cellular damage by the chemical and repair/protection by the host. The Mixed Function Oxidase system is very responsive to xenobiotics and may reflect hazard. A recent electrophilic SE2 mechanism suggested that this was the result of a relationship between the oxidation potential of the induced MFO active site and the C-H bond strength of xenobiotic. This study tested and supported this model of enthalpic biochemical control, demonstrating that an induced active site has the potential to metabolize any C-H bond that is weaker than the C-H bond strength of its inducer. Chlorinated chemicals exhibited a stronger oxidation potential than predicted, presenting a risk of uncontrolled oxidations that may initiate chemical disease.