*2.10.1.1 Epoxidation*

Epoxides are formed by oxidation of double bonds, which can occur on phenyl rings, or alkene part of the organic molecules, and are mediated by microsomal Cyt P450 monoxygenases. Epoxides can be environmentally persistent and highly reactive and can form adducts with cellular macromolecules e.g. proteins, RNA and DNA, often resulting in chemical carcinogenesis and, therefore, not directly advantageous for the organism. However, they are more water-soluble for excretion and can also be further hydrated by *epoxide hydrolases*, which catalyze addition of H2O molecules into the epoxide ring to yield trans-diols [3].
