Coenzyme Q10,Vitamin E,and Dihydrothioctic Acid Cooperatively Prevent Diene Conjugation in Isolated Low-Density Lipoprotein

Coenzyme Q (Q₁₀) and α-tocopherol cooperatively delay the onset of diene conjugation in isolated human low density lipoprotein if supplied in water-soluble preparations to blood serum. Both copper ions and morpholino sydnonimine (in the presence of glucose; SIN-1-glucose) -driven diene conjugation is measurable as soon as both reduced Q₁₀ and tocopherol are oxidized, where tocopherol oxidation starts after 80–90% consumption of reduced Q₁₀. LDL-bound Q₁₀ in turn can be rapidly reduced by dihydrolipoic acid (thioctic acid). This reaction is at least 10 times faster than reduction by ascorbic acid.