Littarru G P, Battino M, Tomasetti M, Mordente A, Santini S, Oradei A, Manto A, Ghirlanda G
Institute of Biochemistry, University of Ancona Medical School, Italy.
Mol Aspects Med. 1994;15 Suppl:s67-72. doi: 10.1016/0098-2997(94)90014-0.
Plasma coenzyme Q10 (CoQ10) is currently assayed in our laboratory for its well-known diagnostic meaning; in fact plasma CoQ10 levels are inversely related to metabolic demand. Definite levels of CoQ10 are also found in white and red blood cell components, as well as in platelets. Plasma and erythrocyte CoQ10 has a well assessed antioxidant role, which was demonstrated through a series of experiments. Erythrocytes previously enriched with exogenous CoQ10 were found more resistant to a hemolysis induced by a free radical initiator. Several enzymatic activities of erythrocyte ghosts were also protected by different side chain CoQ homologues, both when reduced and, although at a lesser extent, in the oxidized state. CoQ was not effective in preventing metal-catalyzed oxidation of erythrocyte membrane enzymes, and this effect is likely to be due to lack of interaction of CoQ with the metal target. Moreover CoQ was able to protect isolated enzymes and erythrocyte membrane bound enzymes from the inactivating effect of free radicals generated by water sonolysis or radiolysis. As far as plasma lipoproteins are concerned it is well known that LDL isolated from healthy volunteers supplemented with CoQ10 are more resistant to peroxidation induced by an azoinitiator. We started to systematically investigate CoQ10 and vitamin E levels in isolated human LDL and HDL. Both CoQ10 and vitamin E concentrations, referred to protein, were found higher in LDL than in HDL. Susceptibility to exogenously applied peroxidation did not correlate with the endogeneous content of the two antioxidants, possibly on the basis of different lipid content of these lipoproteins.
目前，我们实验室检测血浆辅酶Q10（CoQ10）是因其众所周知的诊断意义；事实上，血浆CoQ10水平与代谢需求呈负相关。在白细胞、红细胞成分以及血小板中也发现了一定水平的CoQ10。血浆和红细胞CoQ10具有经过充分评估的抗氧化作用，这已通过一系列实验得到证实。先前富含外源性CoQ10的红细胞对自由基引发剂诱导的溶血更具抵抗力。红细胞空壳的几种酶活性也受到不同侧链CoQ同系物的保护，无论是在还原状态还是氧化状态下（尽管氧化状态下的保护程度较小）。CoQ在预防红细胞膜酶的金属催化氧化方面无效，这种效应可能是由于CoQ与金属靶点缺乏相互作用。此外，CoQ能够保护分离的酶和红细胞膜结合酶免受水超声分解或辐射分解产生的自由基的失活作用。就血浆脂蛋白而言，众所周知，从补充了CoQ10的健康志愿者中分离出的低密度脂蛋白（LDL）对偶氮引发剂诱导的过氧化更具抵抗力。我们开始系统地研究分离出的人LDL和高密度脂蛋白（HDL）中的CoQ10和维生素E水平。相对于蛋白质而言，LDL中的CoQ10和维生素E浓度均高于HDL。对外源性过氧化的敏感性与这两种抗氧化剂的内源性含量无关，这可能是基于这些脂蛋白不同的脂质含量。
