Reactions of oxidized lipids with protein. Part 15. Mechanism of lipoprotein formation from interactions of oxidized ethyl linoleate with egg albumin.

During the reaction of oxidized ethyl linoleate with egg albumin in dry medium at 60 degrees C, hydroperoxides were rapidly decomposed almost completely, while carbonylic anisidine-active and thiobarbituric-acid-active substances were decomposed rapidly in the beginning and only slowly afterwards. Both hydroperoxides and carbonylic oxidation products were substantially more stable in mixtures with cellulose than with albumin. Hydrogen-bonded lipoproteins were rapidly formed, passed through a maximum, and remained nearly constant in the last reaction stage. Covalently bonded lipids in lipoproteins were mainly formed in the stage following the rapid decomposition of hydroperoxides and carbonylic compounds, and immediately following the decrease of hydrogen-bonded lipoproteins. The binding of oxidized lipids into lipoproteins was accompanied by the formation of protein oligomers and by the loss of available lysine.