Effect of vitamin E on the oxidation state of LDL. LDL from 9 subjects was incubated with or without vitamin E before copper oxidation. The samples were subjected to gel electrophoresis and stained with Sudan Black as described previously. This is a representative photograph showing unmodified LDL, LDL preincubated with vitamin E before copper oxidation, LDL incubated with vitamin E, oxidized LDL, and unmodified LDL.