Mechanism of thiyl radical-catalyzed isomerization of unsaturated fatty acid residues in homogeneous solution and in liposomes

Sprinz, H.; Schwinn, J.; Naumov, Sergej; Brede, O.

doi:10.1016/s1388-1981(99)00175-4

Cited by 46 publications

(53 citation statements)

References 20 publications

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“…[3-(2-mercaptoethyl)quinazoline-2,4(1H,3H)dione] [24,26], to amphiphilic thiols such as 2-mercaptoethanol [25,27], which allowed phospholipid reactivity to be compared in homogenous and heterogenous (aqueous) systems. Finally, the use of other hydrophilic thiols, such as 2-mercaptoethylamine [26,28], and more biologically relevant compounds, such as cysteine, glutathione, methionine or some sulfur-containing proteins [25,27,29], allowed a radical stress in biomimetic and cellular systems to be more specifically considered.…”

Section: Lipid Cis-trans Isomerization By Thiyl Radicals In Homogenoumentioning

confidence: 99%

“…Finally, the use of other hydrophilic thiols, such as 2-mercaptoethylamine [26,28], and more biologically relevant compounds, such as cysteine, glutathione, methionine or some sulfur-containing proteins [25,27,29], allowed a radical stress in biomimetic and cellular systems to be more specifically considered. A summary of the main biosynthetic pathways of saturated, MUFA and PUFA (n-6 and n-3 series) residues is given in figure 1, where the IUPAC (International Union of Pure and Applied Chemistry) nomenclatures presenting the length of the carbon atom chain, the number and the position of double bonds are paired with trivial names, when available, that are still largely used in lipid chemistry and biochemistry.…”

Section: Lipid Cis-trans Isomerization By Thiyl Radicals In Homogenoumentioning

confidence: 99%

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Thiyl radicals in biosystems: effects on lipid structures and metabolisms

Ferreri

Kratzsch

Landi

et al. 2005

CMLS, Cell. Mol. Life Sci.

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Thiyl radicals are intermediates of enzyme- and radical-driven biochemical processes, and their potential as reactive species in the biological environment has been somehow underestimated. From organic chemistry, however, it is known that thiyl radicals isomerize the double bonds of unsaturated fatty acids to a mixture with very dominating trans isomers. Recently, this reaction has been particularly studied for biosystems, focusing on the effect of thiyl radicals on the natural all-cis double bonds of unsaturated phospholipids, which undergo a conversion to the unnatural trans form. In this paper we report briefly the role of thiyl radicals in biosystems, describe the main features of the radical-induced cis-trans isomerization process under both in vitro and in vivo conditions, and reflect on some consequences for membrane structures, lipid metabolism and enzymatic reactions.

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Section: Lipid Cis-trans Isomerization By Thiyl Radicals In Homogenoumentioning

confidence: 99%

Section: Lipid Cis-trans Isomerization By Thiyl Radicals In Homogenoumentioning

confidence: 99%

Thiyl radicals in biosystems: effects on lipid structures and metabolisms

Ferreri

Kratzsch

Landi

et al. 2005

CMLS, Cell. Mol. Life Sci.

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“…[12][13][14][15] Recently, it has been shown that biologically relevant thiols (such as glutathione) are able to induce cis-trans isomerization of the double bonds in unsaturated fatty acids. 12,13,16,17 Among biological relevant sulfur species, hydrogen sulfide (H 2 S) is a natural occurring gas with interesting roles in nervous and cardiovascular systems and in pathological conditions such as inflammation. Chemically, the reactions of the simplest S-centered radicals formed from H 2 S were studied using liposomes as biomimetic model.…”

Section: Introductionmentioning

confidence: 99%

Biomimetic chemistry on the protection of cis phospholipid from the thiyl radical isomerization by common antioxidants

Lykakis¹,

Ferreri²,

Chatgilialoglu³

2015

Arkivoc

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Dedicated to Prof. Michael Orfanopoulos on the occasion of his 67th birthday and retirement, and for being a splendid teacher, scientist and friend DOI: http://dx.doi.org/10.3998/ark.5550190.p008.984 AbstractIn this paper the evaluation of cis phospholipids geometry protection from the thiyl radical isomerization in the presence of common antioxidants is studied. Thus, large unilamellar vesicles (LUVs) of glycerophospholipids containing oleate moieties were used as biomimetic model to demonstrate that hydrophilic ascorbic acid and urate, and hydrophobic all-trans retinol acetate and α-tocopherol, are able to inhibit cis-trans isomerization from the thiyl radicals that are known to react as efficient isomerizing species. The synergistic effect obtained by a mix of the hydrophilic and hydrophobic antioxidants at in vivo concentrations is also proved to exert an extraordinary protection for the integrity of cis lipid geometry.

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“…It is likely that thiyl radicals can effectively oxidize polyunsaturated fatty acids (PUFA) via abstraction of bis-allylic hydrogens, yielding pentadienyl radicals (8) with the subsequent formation of conjugated dienes, thiol-fatty acid adducts, and hydroperoxides (9,10). In addition, thiyl radicals can catalytically accelerate cis-trans isomerization of polyunsaturated fatty acid residues in phospholipids (9,10).…”

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“…In addition, thiyl radicals can catalytically accelerate cis-trans isomerization of polyunsaturated fatty acid residues in phospholipids (9,10). These pro-oxidant reactions of thiyl radicals have been detected only in relatively simple chemical systems during the massive production of thiyl radicals induced by pulse radiolysis or chemolysis with azoinitiators.…”

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Glutathione Propagates Oxidative Stress Triggered by Myeloperoxidase in HL-60 Cells

Borisenko

Martin

Zhao

et al. 2004

Journal of Biological Chemistry

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Glutathione acts as a universal scavenger of free radicals at the expense of the formation of the glutathionyl radicals (GS ⅐ ). Here we demonstrated that GS ⅐ radicals specifically interact with a reporter molecule, paramagnetic and non-fluorescent 4-((9-acridinecarbonyl)-amino)-2,2,6,6-tetramethylpiperidine-1-oxyl (Ac-Tempo), and convert it into a non-paramagnetic fluorescent product, identified as 4-((9-acridinecarbonyl)amino)-2,2,6,6-tetramethylpiperidine (Ac-piperidine). Horseradish peroxidase-, myeloperoxidase-, and cyclooxygenasecatalyzed oxidation of phenol in the presence of H 2 O 2 and GSH caused the generation of phenoxyl radicals and GS ⅐ radicals, of which only the latter reacted with Ac-Tempo. Oxidation of several other phenolic compounds (e.g. etoposide and tyrosine) was accompanied by the formation of GS ⅐ radicals along with a characteristic fluorescence response from Ac-Tempo. In myeloperoxidase-rich HL-60 cells treated with H 2 O 2 and phenol, fluorescence microscopic imaging of Ac-Tempo revealed the production of GS ⅐ radicals. A thiol-blocking reagent, N-ethylmaleimide, as well as myeloperoxidase inhibitors (succinyl acetone and azide), blocked formation of fluorescent acridine-piperidine. H 2 O 2 /phenolinduced peroxidation of major classes of phospholipids in HL-60 cells was completely inhibited by Ac-Tempo, indicating that GS ⅐ radicals were responsible for phospholipid peroxidation. Thus, GSH, commonly viewed as a universal free radical scavenger and major intracellular antioxidant, acts as a pro-oxidant during myeloperoxidase-catalyzed metabolism of phenol in HL-60 cells.Thiols are said to fulfill important antioxidant functions in cells and biological fluids. In particular, glutathione, the most abundant intracellular low molecular weight thiol, regulates the content of H 2 O 2 and organic (lipid) hydroperoxides via glutathione peroxidase-catalyzed reactions. GSH is also commonly presumed to act as a universal free radical sink toward a wide variety of different types of free radicals (1-5). Although scavenging of reactive radicals by GSH is believed to be an important antioxidant function of the latter, it may render effective protection only if the sulfur-centered glutathionyl radicals (GS ⅐ ) 1 formed in the scavenging reactions do not further propagate free radical generation. On the contrary, pro-oxidant activity of GSH should be expected if GS ⅐ radicals are reactive enough to interact with and cause damage to vital intracellular molecules.In fact, experiments in model systems indicate that GS ⅐ radicals can abstract hydrogen atoms from carbohydrates such as 2-deoxy-D-ribose and initiate irreversible DNA damage (6). Thiyl radicals are also capable of hydrogen abstraction from ␣-amino C-H bonds of amino acids with the consequent formation of carbon-centered radicals (7). However, reactions of thiyl radicals with carbohydrates and amino acids are reversible; moreover, carbon-centered radicals of carbohydrates and amino acids are stronger oxidants than thiyl radicals, suggesting tha...

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Mechanism of thiyl radical-catalyzed isomerization of unsaturated fatty acid residues in homogeneous solution and in liposomes

Cited by 46 publications

References 20 publications

Thiyl radicals in biosystems: effects on lipid structures and metabolisms

Thiyl radicals in biosystems: effects on lipid structures and metabolisms

Biomimetic chemistry on the protection of cis phospholipid from the thiyl radical isomerization by common antioxidants

Glutathione Propagates Oxidative Stress Triggered by Myeloperoxidase in HL-60 Cells

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