Non‐reactivity of the selenoenzyme glutathione peroxidase with enzymatically hydroperoxidized phospholipids

Grossmann, Adelbert; Wendel, Albrecht

doi:10.1111/j.1432-1033.1983.tb07687.x

Cited by 168 publications

(41 citation statements)

References 34 publications

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“…The seleniumdependent GSH peroxidase does not appear to be involved, because addition of this enzyme did not show a detectable effect. Ths is in agreement with recent findings [26], ruling out the activity of this enzyme with enzymatically generated hydroperoxidized phospholipids as substrate, as long as there is no phospholipase present. We suggest the involvement of the phosholipid hydroperoxide glutathione peroxidase [15].…”

Section: The Ejject Of Thiolssupporting

confidence: 81%

The protection by ascorbate and glutathione against microsomal lipid peroxidation is dependent on vitamin E

Wefers

Sies

1988

European Journal of Biochemistry

334

100

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Lipid peroxidation of rat liver microsomal fractions was monitored by its low-level cheniiluniinescence in preparations from controls and vitamin-E-deficient animals. Measurements were made (a) of the duration of the lag phase T~ after initiation with NADPH/iron-ADP and (b) of the slope of the chemiluminescence increase.In microsomes with normal vitamin E (a-tocopherol) level the lag phase T,, was substantially increased by ascorbate; in contrast, even an enhanced peroxidation was observed with ascorbate in vitamin-E-deficient microsomes. Therefore, the ascorbate-mediated protection of microsomal membranes against lipid peroxidation is dependent on vitamin E in the membrane. In vitamin E deficiency the pro-oxidant effect of ascorbate was abolished when glutathione (GSH) was present.Likewise, GSH does not prolong the lag phase zo in vitamin E deficiency. However, GSH (but not cysteine) exerts an antioxidant effect both in controls and in vitamin E deficiency by decreasing the slope of the chemiluminescence increase during lipid peroxidation. The involvement of GSH in an enzyme-dependent mechanism is suggested.Vitamin E is regarded as the major lipid-soluble antioxidant, preventing oxidative attack of membrane lipids and other membrane-associated compounds (see [ 11 for review). The initiating process by a primary radical R' leads to lipid radicals L', which then add oxygen in a diffusion-limited reaction. The resulting lipid peroxyl radicals continue a chain process.(1) (2) Chain-breaking antioxidants shorten the length of the chain reaction by trapping the peroxyl radical LOO'. Vitamin E has been shown to be a very effective scavenger of these radicals [2, 31, whereas it does not react at comparable rates with carbon-centered radicals [4].Ascorbate [5 -71 and glutathione (GSH) [8 -151 have been described to be involved in several types of protective mechanism. In ESR studies regeneration of vitamin E from the cr-chromanoxyl radical by GSH and vitamin C was detected [lo, 161. In experiments investigating the effect of vitamin E and vitamin C on methyl linoleate peroxidation, vitamin E was kept in the reduced state as long as there was vitamin C present [17]. In addition to this synergistic effect of vitamin C with vitamin E, a direct chain-breaking activity of vitamin C was also reported [17]. In human blood plasma the oxidation of protein sulfhydryl groups is one of the first events when peroxyl radicals are generated [I 81, thus a chain-breaking

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Section: The Ejject Of Thiolssupporting

confidence: 81%

The protection by ascorbate and glutathione against microsomal lipid peroxidation is dependent on vitamin E

Wefers

Sies

1988

European Journal of Biochemistry

334

100

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“…For example, in the case of lipids it has been shown that both Se-dependent GSH peroxidase and GSH transferase isoenzymes inhibit microsomal lipid peroxidation [7], the substrates in both cases being free fatty acid hydroperoxides rapidly released from peroxidized phospholipids by phospholipase Az [7,8]. A recent study with GSH transferase isoenzymes shows that they differ considerably in tiaeir ability to utilize fatty acid hydroperoxides as substrates and that their ability to inhibit lipid peroxidation is proportional to their enzymic activity [9], In the case of DNA, 2/-radiation of aqueous solutions gives rise to pyrimidine hydroperoxide moieties [10] and incubation of peroxidized DNA or thymine hydroperoxide with GHS and rat liver soluble supernatant fraction causes oxidation of GSH implying that these peroxides are substrates for GSH peroxidase activity [5].…”

Section: Introductionmentioning

confidence: 99%

“…Oxygen centred free radicals peroxidize both cellular lipids and DNA [1][2][3][4]: this damage appears to be mitigated by GSH-dependent enzymes [5][6][7][8]. For example, in the case of lipids it has been shown that both Se-dependent GSH peroxidase and GSH transferase isoenzymes inhibit microsomal lipid peroxidation [7], the substrates in both cases being free fatty acid hydroperoxides rapidly released from peroxidized phospholipids by phospholipase Az [7,8].…”

Section: Introductionmentioning

confidence: 99%

Thymine hydroperoxide, a substrate for rat Se‐dependent glutathione peroxidase and glutathione transferase isoenzymes

et al. 1986

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The thymine hydroperoxide, 5‐hydroperoxymethyluracil, is a substrate for Se‐dependent glutathione (GSH) peroxidase and the Se‐independent GSH peroxidase activity associated with the GSH transferase fraction. These enzymes may contribute to repair mechanisms for damage caused by oxygen radicals. GSH transferases 1‐1, 2‐2, 3‐3, 4‐4, 6‐6 and 7‐7 [(1984) Biochem. Pharmacol. 33, 2539–2540] are shown to differ considerably in their ability to utilize this substrate. For example, high activity is found in GSH transferase 6‐6 which is the major isoenzyme in spermatogenic tubules where DNA synthesis is so active and faithful DNA replication so important. The activity of the purified GSH transferase isoenzymes towards 5‐hydroperoxymethyluracil is comparable with their activity towards other endogenous substrates related to cellular peroxidation such as linoleate hydroperoxide and 4‐hydroxynon‐2‐enal or biologically important xenobiotic metabolites such as benzo(a)pyrene‐7,8‐diol‐9,10‐oxide.

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“…Preferential hydrolysis of oxidized fatty acids was demonstrated in isolated cell membranes and artificial membrane preparations, having been documented for cellular, digestive, and venom PLases. 25,[41][42][43] However, it should be noted that intact fatty acyl chains as well as possibly peroxidized fatty acyl chains of endogenous PE were hydrolyzed under the present conditions. PLase A 2 activity can be modified depending on the integrity of membrane phospholipids.…”

Section: Discussionmentioning

confidence: 96%

Enhanced Degradation of Phospholipids by Phospholipase A2 in Liver of Carbon Tetrachloride-Treated Rat.

Ryu¹,

Itabe²,

Mutoh³

et al. 2000

JOURNAL OF HEALTH SCIENCE

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Stimulated phospholipid degradation was observed in liver homogenates harvested from rats who had received an injection of carbon tetrachloride (CCl 4 ). When the liver homogenates obtained from CCl 4 -treated rats were incubated for 1 h at 37°C, approximately half of the phosphatidylethanolamine (PE) was hydrolyzed, producing a stoichiometrical amount of lysophosphatidylethanolamine (LysoPE). The homogenates obtained from control rats showed only poor hydrolytic activity toward endogenous PE. The fatty acid composition of lysoPE produced was essentially identical to that at the sn-1 position of PE, suggesting that A 2 type of phospholipase (PLase A 2 ) was involved in the degradation during incubation. The hydrolysis of endogenous PE was dependent on calcium ion. The hydrolytic activity was almost exclusively associated with the membrane fraction which was precipitated by centrifugation at 10000 × g, and did not require the cytosol fraction. Para-bromophenacylbromide, rabbit antibody against rat 14 kDa type II PLase A 2 , and thielocin A 1 , a specific inhibitor of type II PLase A 2 , suppressed the hydrolysis almost completely. These results indicate that the accelerated degradation of endogenous PE observed in liver homogenates of CCl 4 -treated rat may be mainly due to the activity of the enzyme closely related to type II PLase A 2 .

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Non‐reactivity of the selenoenzyme glutathione peroxidase with enzymatically hydroperoxidized phospholipids

Cited by 168 publications

References 34 publications

The protection by ascorbate and glutathione against microsomal lipid peroxidation is dependent on vitamin E

The protection by ascorbate and glutathione against microsomal lipid peroxidation is dependent on vitamin E

Thymine hydroperoxide, a substrate for rat Se‐dependent glutathione peroxidase and glutathione transferase isoenzymes

Enhanced Degradation of Phospholipids by Phospholipase A2 in Liver of Carbon Tetrachloride-Treated Rat.

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