T
Coq5 MLISSrIVrSSLVNVPLrLS_r_C _F_ TQ A HrACk Coq6 MFFSkVMLTrr L VrGLATA kSSAPkL C 8 MVTNMVkLrNLrrLYCSSrLL_r_ TJ_QNGrIS SVSS 76 79 77 79 78 79 Note N.D., not done k, r, Positively charged residues , negatively charged amino acids. T Indicates site of mature amino terminus of Coq polypeptide as predicted by the 3 amino acid motif underlined residues present in leader sequences of polypeptides targeted to the mitochondria matrix compartment Hendrick et al., 1989 . References for in vitro import...
Biochemical Pathogenesis Of Alcohol Induced Fatty Liver
Hepatic metabolism of alcohol results in an increase in the cytosolic NADH NAD ,33 which could lead to i inhibition of -oxidation and fat accumulation via mitochondrial NADH NAD ,34 or ii increased cytosolic ratio of phosphate and enhanced esterification. 35,36 However, in animal studies, addition of oxidants such as methylene blue to the diet does not prevent alcoholic fatty liver37 and hepatic redox changes are attenuated to levels seen in control animals after some months of alcohol feeding...
Coenzyme Q Semiquinone Radical Reduces Vitamin E Phenoxyl Radical
Electron transport in membranes is always accompanied by generation and release of superoxide, whose level may become very high under some conditions e.g., during the oxidative burst of phagocytic cells, or in the presence of redox-cycling drugs .1446 Overproduction of superoxide creates prooxidant conditions, resulting in depletion of antioxidants and development of oxidative stress. Superoxide readily reduces coenzyme Q to form ubisemiquinone and ubiquinol, directly or via disproportionate of...
quenching reaction of singlet oxygen by biological hydroquinones
Singlet oxygen 1O2 was generated by the thermal decomposition of the 3- 1,4-epidioxy-4-methyl-l, 4-dihydro-l-naphthyl propionic acid EP Figure 3.2 .28 2,5-Diphenyl-3,4-benzofuran DPBF was used as standard compound. The overall rate constants kQ kq kcr for the reaction of 1O2 with hydroquinones 1, 2, 5-13 were determined in ethanol by Eq. 3.16 derived from the steady-state treatment of Scheme 1.44 where SO and SS are slopes of the first-order plots of disappearance of 1O2 acceptor, DPBF, in the...
extramitochondrial coenzyme q in the defense against oxidative stress
Oxidative stress can be defined as the result of oxidative changes in the cellular redox status. This status is the consequence of the equilibrium between oxidants and physiological antioxidants. The main sources of oxidative stress are oxygen and its ROS. Extracellular ROS mainly come from the interaction between transition metal ions and oxygen in solution, or by the radiation-induced hydrolysis. The most important intracellular sources of ROS are oxygen-metabolizing organelles such as...
Introduction Tiq
Ubiquinone-10, also known as coenzyme Q10, is best known for its role in energy production by mitochondria, where it functions as an essential proton-electron carrier in the inner mitochondrial membrane.1 The human body contains about 1.6 g ubiquinone-10 which is present in nearly all tissues.2 Ubiquinol-10, the reduced form of ubiquinone-10, is a potent lipophilic antioxidant for protection of lipids in different biological and model systems.3-5 Ubiquinol-10 represents more than 80 of the...
Interaction With Other Antioxidants
The radical-scavenging antioxidants function not only individually but also cooperatively and sometimes synergistically with other antioxidants. The most well-documented interaction is the one between vitamin C and vitamin E.25 Vitamin C present in the aqueous phase, efficiently reduces the vitamin E radical located within the membranes and lipoproteins to regenerate vitamin E and to inhibit, if any, the chain initiation induced by the vitamin E radical. It has been found that ubiquinol reduces...
Info Mlr
38. Kontush, A., H bner, C., Finckh, B., Kohlsch tter, A., and Ulrike, B., Antioxidative activity of ubiquinol-10 at physiologic concentrations in human low density lipoprotein, Biochim. Biophys. Acta, 1258, 177-187, 1995. 39. Lass, A. and Sohal, R. S., Electron transport-linked ubiquinone-dependent recycling of a-tocopherol inhibits autooxidation of mitochondrial membranes, Arch. Biochem. Biophys., 352, 229-236, 1998. 40. Matsura, T., Yamada, K., and Kawasaki, T., Difference in antioxidant...
Gian Paolo Littarru and Maurizio Battino CONTENTS
14.2 Coenzyme Q Deficiency in Tissues and 14.3 Coenzyme Q Administration and Peroxidation 14.3.1 CoQ1 Administration and Oxidative Stress at the Myocardial 14.3.2 CoQ10 Effect on the Senescent 14.3.3 CoQ10 Treatment and Ischemic Brain 14.3.4 Effect of Chronic CoQ10 Supplementation on Plasma Lipoprotein The bioenergetic role of coenzyme Q CoQ in mitochondria as well as its essential role in other redox chains is well accepted. What is more often debated is its antioxidant function and the...
Info Lhn
Beyer, R. E., The participation of coenzyme Q in free radical production and antioxidation, Free Radic. Biol. Med., 8, 545-565, 1990. Frei, B., Kim, M., and Ames, B. N., Ubiquinol-10 is an effective lipid-soluble antioxidant at physiological concentrations, Proc. Natl. Acad. Sci. U.S.A., 87, 4879-4883, 1990. Yamamoto, Y., Komura, E., and Niki, E., Antioxidant activity of ubiquinol in solution and phosphatidylcholine liposome, J. Nutr. Sci. Vitaminol., 36, 505-511, 1990. Mukai, K., Kikuchi, S.,...
Info Yuo
Topography of Coenzyme Q in Membranes 2.2 Amphipathic Character of Coenzyme 2.3 Interaction of Coenzyme Q with Model 2.4 Incorporation of Coenzyme Q into Phospholipid 2.5 Effect of Polyisoprene Chain 2.6 Spectroscopic Studies of Coenzyme Q-Phospholipid 2.7 Phase Separation of Coenzyme Q in Model 2.8 Spectroscopic Probe Studies of Coenzyme Q 2.9 Fluorescence Probe 2.10 Vibrational Spectroscopic 2.11 Interaction of Coenzyme Q with Nonbilayer Forming 2.12 Arrangement of Coenzyme Q in Biological...
Contributors
MCA Research Laboratory Department of Physiology University of Turku Turku, Finland National Public Health Institute Department of Mental Health and Alcohol Research Helsinki, Finland Sir James Spence Institute of Child Health Royal Victoria Infirmary Newcastle-upon-Tyne, United Kingdom Institute of Biochemistry University of Ancona Medical School Ancona, Italy Department of Chemistry and Biochemistry and the Molecular Biology Institute University of California-Los Angeles Los Angeles,...
About the Editors
Valerian E. Kagan received his Ph.D. degree in biochemistry and biophysics from M.V. Lomonosov Moscow State University, and his D.Sc. degree from the USSR Academy of Sciences, Moscow. In 1983, Dr. Kagan was awarded the State Prize of the USSR for science. From 1976 through 1983, Dr. Kagan was an associate research professor at M.V. Lomonosov Moscow State University in Moscow, and from 1983 to 1989 he was a research professor and head of the Membrane Biostabilization Group in the Institute of...