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Book ChapterDOI

Microsomal lipid peroxidation.

01 Jan 1978-Methods in Enzymology (METHODS IN ENZYMOLOGY)-Vol. 52, pp 302-310
TL;DR: This chapter discusses microsomal lipid peroxidation, a complex process known to occur in both plants and animals that involves the formation and propagation of lipid radicals, the uptake of oxygen, a rearrangement of the double bonds in unsaturated lipids, and the eventual destruction of membrane lipids.
Abstract: Publisher Summary This chapter discusses microsomal lipid peroxidation Lipid peroxidation is a complex process known to occur in both plants and animals It involves the formation and propagation of lipid radicals, the uptake of oxygen, a rearrangement of the double bonds in unsaturated lipids, and the eventual destruction of membrane lipids, producing a variety of breakdown products, including alcohols, ketones, aldehydes, and ethers Biological membranes are often rich in unsaturated fatty acids and bathed in an oxygen-rich, metal-containing fluid Lipid peroxidation begins with the abstraction of a hydrogen atom from an unsaturated fatty acid, resulting in the formation of a lipid radical The formation of lipid endoperoxides in unsaturated fatty acids containing at least 3 methylene interrupted double bonds can lead to the formation of malondialdehyde as a breakdown product Nonenzymic peroxidation of microsomal membranes also occurs and is probably mediated in part by endogenous hemoproteins and transition metals The direct measurement of lipid hydroperoxides has an advantage over the thiobarbituric acid assay in that it permits a more accurate comparison of lipid peroxide levels in dissimilar lipid membranes
Citations
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Journal ArticleDOI

2,446 citations

Journal ArticleDOI
TL;DR: An increased concentration of end products of lipid peroxidation is the evidence most frequently quoted for the involvement of free radicals in human disease, but it is likely that increased oxidative damage occurs in most, if not all, human diseases and plays a significant pathological role in only some of them.

2,204 citations

Journal ArticleDOI
TL;DR: The concept that AMD can be attributed to cumulative oxidative stress is enticing, but remains unproven, and the effect of nutritional antioxidant supplements on the onset and natural course of age-related macular disease is currently being evaluated.

1,870 citations

Journal ArticleDOI
TL;DR: Results obtained suggest that growth of pea plants with CdCl(2) can induce a concentration-dependent oxidative stress situation in leaves, characterized by an accumulation of lipid peroxides and oxidized proteins as a result of the inhibition of the antioxidant systems.
Abstract: The effect of growing pea (Pisum sativum L.) plants with CdCl(2) (0-50 microM) on different plant physiological parameters and antioxidative enzymes of leaves was studied in order to know the possible involvement of this metal in the generation of oxidative stress. In roots and leaves of pea plants Cd produced a significant inhibition of growth as well as a reduction in the transpiration and photosynthesis rate, chlorophyll content of leaves, and an alteration in the nutrient status in both roots and leaves. The ultrastructural analysis of leaves from plants grown with 50 microM CdCl(2), showed cell disturbances characterized by an increase of mesophyll cell size, and a reduction of intercellular spaces, as well as severe disturbances in chloroplast structure. Alterations in the activated oxygen metabolism of pea plants were also detected, as evidenced by an increase in lipid peroxidation and carbonyl-groups content, as well as a decrease in catalase, SOD and, to a lesser extent, guaiacol peroxidase activities. Glutathione reductase activity did not show significant changes as a result of Cd treatment. A strong reduction of chloroplastic and cytosolic Cu,Zn-SODs by Cd was found, and to a lesser extent of Fe-SOD, while Mn-SOD was only affected by the highest Cd concentrations. Catalase isoenzymes responded differentially, the most acidic isoforms being the most sensitive to Cd treatment. Results obtained suggest that growth of pea plants with CdCl(2) can induce a concentration-dependent oxidative stress situation in leaves, characterized by an accumulation of lipid peroxides and oxidized proteins as a result of the inhibition of the antioxidant systems. These results, together with the ultrastructural data, point to a possible induction of leaf senescence by cadmium.

1,340 citations

Journal ArticleDOI
TL;DR: Currently available assays for measuring peroxidation are reviewed--the more specific the assay used, the less peroxide is found in healthy human tissues and body fluids.

1,241 citations

References
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Book
01 Jan 1972
TL;DR: This short review of free radicals discusses certain types of free radical, such as nitroxyl-radicals and free radicals stabilized by steric or derealization features, which are stable enough to be crystallised and stored at temperatures above 0°.
Abstract: Free radicals are molecules or molecular fragments containing a single unpaired electron. In general, free radicals are reactive chemically, some (e.g. HO•) being extremely reactive. However, certain types of free radical, such as nitroxyl-radicals and free radicals stabilized by steric or derealization features, are much less reactive and a few (e.g. diphenyl picryl hydrazyl) are stable enough to be crystallised and stored at temperatures above 0°. Table 1 gives the general structures of free radicals that will be discussed in this short review.

1,643 citations

Journal ArticleDOI
TL;DR: Phospholipid arachidonate has been established as the major source of the malonaldehyde produced during microsomal lipid peroxidation.
Abstract: The thiobarbituric acid reacting material produced during enzymatic microsomal lipid peroxidation has been identified as malonaldehyde. The malonaldehyde was condensed with urea to form 2-hydroxy-pyrimidine, which was identified by its ultraviolet spectrum, chromato-graphic properties, and mass spectrum. Incubations with phosphatidyl choline labelled with tritiated arachidonate yielded 2-hydroxy-pyrimidine with a specific activity nearly equal to that of the phospholipid arachidonate. Incubations with tritiated arachidonic acid yielded 2-hydroxy-pyrimidine with a specific activity nearly 2 orders of magnitude less than that of free arachidonic acid. Therefore, phospholipid arachidonate has been established as the major source of the malonaldehyde produced during microsomal lipid peroxidation.

1,391 citations

Journal ArticleDOI
TL;DR: It is considered that lipid peroxide formation occurs as a result of the operation of the microsomal electron-transport chain switching from hydroxylation to oxidize unsaturated lipids of the endoplasmic reticulum.
Abstract: 1. Liver microsomes form lipid peroxide when incubated with ascorbate or NADPH, but not with NADH. Increasing the concentration of ascorbate beyond the optimum (0.5mm) decreases the rate of lipid peroxide formation, but this effect does not occur with NADPH. Other reducing agents such as p-phenylenediamine or ferricyanide were not able to replace ascorbate and induce lipid peroxide formation. 2. The rate of ascorbate-induced peroxidation is optimum at pH6.0 whereas the rate of the NADPH system is optimum at pH7.0. Both systems require phosphate for maximum activity. 3. Lipid peroxide formation occurs at the maximum specific rate in very dilute microsome suspensions (0.15mg. of protein/ml.). 4. Treatment of microsomes with deoxycholate and other detergents causes membrane disintegration and inhibits lipid peroxide formation. 5. Lipid peroxide formation is accompanied by a rapid uptake of oxygen and there is a large excess of oxygen utilized for each molecule of malonaldehyde measured in the peroxide method. 6. Boiled microsomes form lipid peroxide in the presence of ascorbate, but not if NADPH is added. 7. Lipid peroxide formation induced by NADPH is strongly inhibited by p-chloromercuribenzoate, weakly inhibited by N-ethylmaleimide and unaffected by iodoacetamide. Ascorbate-induced peroxidation in untreated microsomes is unaffected by p-chloromercuribenzoate, but inhibited if boiled microsomes are used. These experiments may be interpreted on the basis that a ferredoxin-type protein forms part of the system in which NADPH induces lipid peroxide formation. 8. Most heavy-metal ions, with the exception of inorganic iron (Fe(2+) or Fe(3+)), which activates, inhibit both ascorbate-induced and NADPH-induced peroxidation. Mg(2+) increases the rate of peroxidation whereas Ca(2+) inhibits it. 9. Lipid peroxide formation is inhibited strongly by GSH and weakly by cysteine. Ascorbate-induced peroxidation is much more sensitive than NADPH-induced peroxidation. 10. Peroxidation is strongly inhibited by addition of low concentrations (0.01-0.1mm) of cytochrome c or of haemoglobin. 11. It is considered that lipid peroxide formation occurs as a result of the operation of the microsomal electron-transport chain switching from hydroxylation to oxidize unsaturated lipids of the endoplasmic reticulum.

510 citations

Journal ArticleDOI
TL;DR: Several broad lines of scientific evidence showing that vitamin E functions as a lipid antioxidant, inhibiting the destructive peroxidation of polyunsaturated lipids, have been presented in recent reviews are presented.
Abstract: Several broad lines of scientific evidence showing that vitamin E functions as a lipid antioxidant, inhibiting the destructive peroxidation of polyunsaturated lipids, have been presented in recent reviews.'-Q Further, the function of vitamin E is a very broad topic, study of which can be based in part on knowledge of other lipid antioxidant reactions and interrelationships. Also, the reactions of and the damage caused by free radical peroxidation of lipids are complex topics, and in a relative sense the mechanisms of damage are not well understood, although they appear to have counterparts in radiation biochemistry. In view of the breadth of this topic, it is appropriate in the first section of this paper to direct attention to the major review sources in which information on the subject is summarized, and to some recently published papers. TABLE 1 lists some of the major factors in the suppression of lipid peroxidation. On the basis of the chemical properties of a-tocopherol and the mechanisms of antioxidation, a-tocopherol would be expected to react as a chain-breaking antioxidant in the inhibition of the free radical peroxidation of lipids. The propagation reaction in which the polyunsaturated lipid LH is peroxidized, L' + OZ'LOZ' LOZ. + LH+ LOOH + L' 1

454 citations

Journal ArticleDOI
18 Jan 1974-Science
TL;DR: Ethane evolution in vivo was stimulated by prior administration of phenobarbital and it was diminished by prior injection of α-tocopherol, suggesting that ethane production may be a useful index of lipid peroxidation in tissue homogenates and in intact animals.
Abstract: Homogenates of mouse liver and brain at 37 degrees C spontaneously formed lipid peroxides and simultaneously evolved ethane. alpha-Tocopherol, a lipid antioxidant, blocked ethane formation. When mice were injected with carbon tetrachloride (a liquid prooxidant for liver), the animals produced ethane. Ethane evolution in vivo was stimulated by prior administration of phenobarbital and it was diminished by prior injection of alpha-tocopherol. These data suggest that ethane production may be a useful index of lipid peroxidation in tissue homogenates and in intact animals.

420 citations