Reactive Absorption of Ozone by Aqueous Biomolecule Solutions: Implications for the Role of Sulfhydryl Compounds as Targets for Ozone

Kanofsky, Jeffrey R.; Sima, Paul D.

doi:10.1006/abbi.1995.1009

Cited by 61 publications

(43 citation statements)

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“…Radioactive [4][5][6][7][8][9][10][11][12][13][14] C]cholesterol (45-60 mCi/mmol dissolved in ethanol) was purchased from PerkinElmer Life Sciences. Radioactive [1-14 C]acetate (56.6 mCi/mmol dissolved in ethanol) was purchased from PerkinElmer Life Sciences.…”

Section: Methodsmentioning

confidence: 99%

“…Sodium borohydride reduction of ␣-epoxide, ␤-epoxide, and the unknown metabolite was carried out by adding an excess of NaBH 4 to the oxysterol dissolved in ethanol for 2 h followed by iso-octane extraction. Epoxide hydrolysis to vicinal diols of ␣-epoxide, ␤-epoxide, and the unknown metabolite was carried out by treating 5 g of the oxysterol with 30 l of perchloric acid in 0.5 ml of tetrahydrofuran/H 2 O/acetone (v/v/v, 4:1:0.5) and stirring for 4 h at room temperature (24).…”

Section: Formation Of Active Oxysterols During Cholesterol Ozonolysismentioning

confidence: 99%

“…However, after 24 h of incubation, the low levels of this metabolite did not correspond with the marked decrease in ␤-epoxide over this period, suggesting another metabolite might in fact be formed. A new metabolite was observed with an [M ϩ NH 4 ] ϩ ion at m/z 436 that could be collisionally activated to yield a product ion at m/z 383. This same mass transition had been used previously to detect an expected ozonolysis product, namely 3␤-hydroxy-5-oxo-5,6-secocholestane-6-al (5,6-seco-sterol).…”

Section: Fig 3 Formation Of 5␤6␤-cholesterol Epoxide In 16-hbe Celmentioning

confidence: 99%

“…A small portion of the HPLC effluent was monitored by MS/MS for the transition of the metabolite, and the fraction containing this metabolite was collected. Collisional activation of the [M ϩ NH 4 ] ϩ ion formed during electrospray ionization of this fraction yielded a product ion mass spectrum that was identical to the collisional activation of 5,6-seco-sterol ([M ϩ NH 4 ] ϩ at m/z 436) and provided little unique structural information. The collision-induced dissociation of the ion derived from this metabolite yielded an ion corresponding to the loss of NH 3 (m/z 419) and three additional ions corresponding to the subsequent losses of each oxygen atom as water (m/z 401, 383, and 365).…”

Section: Fig 3 Formation Of 5␤6␤-cholesterol Epoxide In 16-hbe Celmentioning

confidence: 99%

“…It has been hypothesized that the very high chemical reactivity of ozone limits the distribution of this gas in the pulmonary system, preventing direct exposure to the cellular components of the lung. In part ozone may react with the various components of the epithelial cell lining fluid in the lung, also known as pulmonary surfactant, which includes proteins, lipids, and single electron antioxidant agents such as ascorbic acid (3)(4)(5). Because of the very high reactivity of ozone with lipids containing double bonds, considerable emphasis has been placed on the reaction of ozone with lipid compounds in the lungs and the possibility that the adverse effects of ozone are mediated by lipid-ozonized products (6).…”

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Formation of Biologically Active Oxysterols during Ozonolysis of Cholesterol Present in Lung Surfactant

Pulfer

Murphy

2004

Journal of Biological Chemistry

104

102

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Exposure of the lung to concentrations of ozone found in ambient air is known to cause toxicity to the epithelial cells of the lung. Because of the chemical reactivity of ozone, it likely reacts with target molecules in pulmonary surfactant, a lipid-rich material that lines the epithelial cells in the airways. Phospholipids containing unsaturated fatty acyl groups and cholesterol would be susceptible to attack by ozone, which may lead to the formation of cytotoxic products. Whereas free radicalderived oxidized cholesterol products have been frequently studied for their cytotoxic effects, ozonized cholesterol products have not been studied, although they could reasonably play a role in the toxicity of ozone. The reaction of ozone with cholesterol yielded a complex series of products including 3␤-hydroxy-5-oxo-5,6-secocholestan-6-al, 5-hydroperoxy-B-homo-6-oxa-cholestan-3␤,7a-diol, and 5␤,6␤-epoxycholesterol. Mass spectrometry and radioactive monitoring were used to identify the major cholesterol-derived product during the reaction of 2 ppm ozone in surfactant as 5␤,6␤-epoxycholesterol, which is only a minor product during ozonolysis of cholesterol in solution. A dose-dependent formation of 5␤,6␤-epoxycholesterol was also seen during direct exposure of intact cultured human bronchial epithelial cells (16-HBE) to ozone. Studies of the metabolism of this epoxide in lung epithelial cells yielded small amounts of the expected metabolite, cholestan-3␤,5␣,6␤-triol, and more abundant levels of an unexpected metabolite, cholestan-6-oxo-3␤,5␣-diol. Both 5␤,6␤-epoxycholesterol and cholestan-6-oxo-3␤,5␣-diol were shown to be cytotoxic to cultured 16-HBE cells. A possible mechanism for cytotoxicity is the ability of these oxysterols to inhibit isoprenoid-based cholesterol biosynthesis in these cells.Human exposure to 0.2 ppm levels of ozone in ambient air has been shown to cause numerous pulmonary effects such as increased airway inflammation and decreased pulmonary function (1, 2). Studies of ozone in animals using up to 3 ppm ozone have been shown to cause increased airway hyperresponsiveness and epithelial cell death. It has been hypothesized that the very high chemical reactivity of ozone limits the distribution of this gas in the pulmonary system, preventing direct exposure to the cellular components of the lung. In part ozone may react with the various components of the epithelial cell lining fluid in the lung, also known as pulmonary surfactant, which includes proteins, lipids, and single electron antioxidant agents such as ascorbic acid (3-5). Because of the very high reactivity of ozone with lipids containing double bonds, considerable emphasis has been placed on the reaction of ozone with lipid compounds in the lungs and the possibility that the adverse effects of ozone are mediated by lipid-ozonized products (6). Evidence in support of this theory has been accumulating with the identification of biologically active phospholipids (7) such as 1-hexadecanoyl-2-(9-oxo-nonanoyl)-glycerophosphocholine, found following oz...

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Section: Methodsmentioning

confidence: 99%

Section: Formation Of Active Oxysterols During Cholesterol Ozonolysismentioning

confidence: 99%

Section: Fig 3 Formation Of 5␤6␤-cholesterol Epoxide In 16-hbe Celmentioning

confidence: 99%

Section: Fig 3 Formation Of 5␤6␤-cholesterol Epoxide In 16-hbe Celmentioning

confidence: 99%

mentioning

confidence: 99%

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Formation of Biologically Active Oxysterols during Ozonolysis of Cholesterol Present in Lung Surfactant

Pulfer

Murphy

2004

Journal of Biological Chemistry

104

102

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Gel‐based proteomics reveals potential novel protein markers of ozone stress in leaves of cultivated bean and maize species of Panama

et al. 2007

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We examined responses of cultivated bean (Phaseolus vulgaris L. cv. IDIAP R-3) and maize (Zea mays L. cv. Guarare 8128) plants exposed to ozone (O(3)) using a leaf injury assessment and proteomics approach. Plants grown for 16 days in greenhouse were transferred to an O(3) chamber and exposed continuously to 0.2 ppm O(3) or filtered pollutant-free air for up to 72 h. CBB-stained gels revealed changes in ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) protein. By Western analysis changes in marker proteins for O(3) damage in leaves by 1-DE were checked. In bean leaves, two superoxide dismutase (SOD) protein (19 and 20 kDa) were dramatically decreased, while ascorbate peroxidase (APX, 25 kDa), small heat shock protein (HSP, 33 kDa), and a naringenin-7-O-methyltransferase (NOMT, 42 kDa) were increased by O(3). In maize leaves, expression levels of catalase (increased), SOD (decreased), and APX (increased) were drastically changed by O(3) depending on the leaf stage, whereas crossreacting HSPs (24 and 30 kDa) and NOMT (41 kDa) proteins were strongly increased in O(3)-stressed younger leaves. These results indicated a clear modulation of oxidative stress-, heat shock-, and secondary metabolism-related proteins by O(3). Finally, 2-DE at 72 h after O(3) exposure revealed changes (induction/suppression) in expression levels of 25 and 12 protein spots in bean and maize leaves, respectively. Out of these, ten and nine nonredundant proteins in bean and maize, respectively, were identified by MS. A novel pathogenesis-related protein 2 may serve as a potential marker for O(3) stress in bean.

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Ozone oxidation of cysteine in optically trapped aqueous micro‐droplets

Chang

2023

J Chinese Chemical Soc

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The ozone (O3) oxidation kinetics of cysteine in aqueous micro‐droplets at different acidities is investigated in this study via aerosol optical tweezers coupled with Raman spectroscopy. This study exploits the O3 oxidation of cysteine near the interface of micro‐droplets as a model system to elucidate the oxidation damage of amino acids in biosurfaces. For each optically trapped micro‐droplet, Raman spectroscopy is used to determine its droplet radius, concentrations of solutes, and droplet pH, as well as their time evolutions during the kinetics measurements. The bimolecular rate coefficients of the cysteine + O3 reaction measured in micro‐droplets are around 4 × 105 M−1 s−1 and 2 × 104 M−1 s−1 for pH ≈ 5 and 0.5, respectively. These results agree with the previous bulk measurements, indicating that the observed aerosol kinetics can be solely rationalized via diffusion‐limited kinetics. The results also indicate that a high‐ionic strength could enhance the cysteine + O3 reaction, particularly for the zwitterion form of cysteine. The results imply that when surfactant proteins in lung fluids are exposed to ambient O3, the cysteine residues in proteins will be attacked by O3 at first due to the high reactivity of the thiol moiety in cysteine.

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Reactive Absorption of Ozone by Aqueous Biomolecule Solutions: Implications for the Role of Sulfhydryl Compounds as Targets for Ozone

Cited by 61 publications

References 0 publications

Formation of Biologically Active Oxysterols during Ozonolysis of Cholesterol Present in Lung Surfactant

Formation of Biologically Active Oxysterols during Ozonolysis of Cholesterol Present in Lung Surfactant

Gel‐based proteomics reveals potential novel protein markers of ozone stress in leaves of cultivated bean and maize species of Panama

Ozone oxidation of cysteine in optically trapped aqueous micro‐droplets

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