Lipidperoxidation

Lower lipid peroxidation refers to the oxidative degradation of lipids. In this process, "steal" electrons from free radicals in lipids of the cell membrane and cause a chain reaction that leads to cell damage. About lipid peroxidation occurs in low-density lipoprotein ( a lipoprotein that transports lipids in the blood ) to oxidative modifications that lead through the formation of foam cells to atherosclerosis. Lipid peroxidation is also responsible for the destruction of animal and vegetable oils and fats ( " rancid "). Mostly polyunsaturated fatty acids affected because these numerous double bonds include, between which there are particularly reactive methyl groups.

Start reaction ( Initiation )

By reaction of a fatty acid ( LH) with a free radical is formed, a reactive fatty acid radical ( L *) is added to the next step in the O2 and lipid peroxyl radical ( LOO *) is generated, which then results in a chain reaction. In biological systems, there are numerous initiators - it's often reactive oxygen species. Enzymes such as lipoxygenases, peroxidases with H2O2, myeloperoxidase with H2O2/Cl- or hemoglobin with H2O2 as well as macrophages can generate free radicals that cause lipid peroxidation.

Follow-up reaction ( prolongation)

The resulting fatty acid - peroxyl radical can now transmit its function to other unsaturated fatty acids, that, in turn, O2 is added, keeping the chain reaction or react with a molecule having anti -oxidant properties (such as α -tocopherol and γ -tocopherol) then the chain reaction is slowed or interrupted. The radical chain reaction is mostly only into full swing as soon as all antioxidants are completely consumed.

Termination reaction ( Termination)

The chain reaction is only interrupted if: ( 1) a stable non- radical is formed by reaction of two radicals. (2) the unsaturated fatty acids are consumed ( 3 ) antioxidants scavenge all radicals

There are numerous natural fat-soluble antioxidants (e.g., are in the human low density lipoprotein particles, on average, per α -tocopherol 7 molecules present) to prevent complete Ausoxidieren of biological entities in living organisms.