Oxidized Lipids Formed Non-enzymatically by Reactive Oxygen Species

Abstract

The evolution of living organisms in an oxidizing atmosphere has resulted in a complex array of antioxidation mechanisms within cells to protect critical biomolecules from oxidative modifications. Despite this, oxidation of biomolecules as a result of exposure to reactive oxygen species is a constant biochemical battle. Because lipids present themselves often as initial barriers to the free diffusion of reactive oxygen species into the cell, they themselves become targets of oxidation reactions. By and large, the resulting structures are not controlled by enzymatic mechanisms and thus are not programmed by the human genome. Their formation is controlled by chemical reaction mechanisms, and a diverse array of products are made, depending upon the reactive oxygen species as well as the nature of the lipid target. In most cases, these molecules are readily degraded and recycled into the essential building blocks of the cell, but there are some oxidized lipids that escape such protective mechanisms and can exert profound, deleterious effect on cells.