Epoxide hydrolase 1 is an enzyme encoded by the EPHX1 gene. EPHX1 is a critical biotransformation enzyme in both the detoxification and activation of potentially genotoxic epoxides. Epoxide hydrolase plays an important role in both the activation and detoxification of exogenous chemicals such as polycyclic aromatic hydrocarbons (PAH). PAHs can be found in petrol, car fumes, smoked foods, and cigarette smoke.
EPHX1 expression is usually higher in the liver and other metabolizing organs such as testis, adrenal gland, lung, kidney, brain, prostate, heart which suggests that EPHX1 may ensure widespread defense against potential genotoxic epoxides.
The TT genotype is associated with being a fast metabolizer. If the enzyme works too fast, it can lead to increased production of the harmful reactive intermediates and accumulation of toxic by-products. This increases the risk of DNA damage and cancer. It is important to determine your genotype for CYP1A1 to assess your overall risk for an oxidative load and then increase your antioxidant protection through diet, supplementation, and making non-toxic environment choices.