The mechanism of the hypochlorite‐induced lipid peroxidation

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Abstract
The article reviews data related to the role of exogenic hypochlorite (HOCl/OCl−) and hypochlorite produced by myeloperoxidase catalysis in initiation of lipid peroxidation (LPO) in phospholipid membranes and human blood lipoproteins (LP). It has been shown that HOCl/OCl− promotes free radical lipid oxidation in liposomes and LP that is followed by the formation of LPO products: hydroperoxides, conjugated dienes, TBARS, and fluorescent products. Water soluble reactive substances •O2−, H2O2, Fe2+) which can be present in the reaction mixture as a dopant are not the source of free radicals and do not participate in HOCl/OCl−‐induced LPO at the initiation step. The main reaction of HOCl/OCl− with unsaturated lipid is probably the generation of chlorohydrins. However, this reaction is not accompanied by generation of free radicals and LPO. HOCl/OCl− reacts efficiently with TBARS of aldehydic nature. It is likely that the reaction proceeds without the participation of free radicals. Among the compounds of a peroxide nature (hydro‐, dialkyl‐, diacyl‐, alkyl‐acyl‐peroxide groups and epoxides) only hydroperoxides react with HOCl/OCl−. This reaction is accompanied by the production of free radicals (but not singlet oxygen), probably alkoxyl radicals, which may play a role in the initiation of HOCl/OCl−‐induced LPO.