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Kirman CR, Li AA, Sheehan PJ, Bus JS, Lewis RC, Hays SM. Ethylene oxide review: characterization of total exposure via endogenous and exogenous pathways and their implications to risk assessment and risk management. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2021; 24:1-29. [PMID: 33323046 DOI: 10.1080/10937404.2020.1852988] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
This review is intended to provide risk assessors and risk managers with a better understanding of issues associated with total exposures of human populations to ethylene oxide from endogenous and exogenous pathways. Biomonitoring of human populations and lab animals exposed to ethylene oxide has relied upon the detection of hemoglobin adducts such as 2-hydroxyethylvaline (HEV), which provides a useful measure of total exposure to ethylene oxide from all pathways. Recent biomonitoring data from CDC provide an excellent characterization of total exposure to ethylene oxide to the general U.S. population by demographic factors such as age, gender, and race as well as smoking habit, which might be comparable to previous measurements reported for humans and lab animals. The biochemical pathways including gastrointestinal (production by bacteria) and systemic (enzymatic production) pathways by which endogenous ethylene is generated and converted to ethylene oxide are described. The relative importance of endogenous pathways and exogenous pathways via ambient air or tobacco smoke was quantified based upon available data to characterize their relative importance to total exposure. Considerable variation was noted for HEV measurements in human populations, and important sources of variation for all pathways are discussed. Issues related to risk assessment and risk management of human populations exposed to ethylene oxide are provided within the context of characterizing total exposure, and data needs for supporting future risk assessment identified.
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Affiliation(s)
| | - A A Li
- Exponent , Oakland, CA, USA
| | | | - J S Bus
- Exponent , Alexandria, MI, USA
| | | | - S M Hays
- Summit Toxicology , Bozeman, MT, USA
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Filser JG, Klein D. A physiologically based toxicokinetic model for inhaled ethylene and ethylene oxide in mouse, rat, and human. Toxicol Lett 2018; 286:54-79. [DOI: 10.1016/j.toxlet.2017.07.896] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 07/20/2017] [Accepted: 07/25/2017] [Indexed: 01/18/2023]
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Su T, Tan Y, Tsui MS, Yi H, Fu XQ, Li T, Chan CL, Guo H, Li YX, Zhu PL, Tse AKW, Cao H, Lu AP, Yu ZL. Metabolomics reveals the mechanisms for the cardiotoxicity of Pinelliae Rhizoma and the toxicity-reducing effect of processing. Sci Rep 2016; 6:34692. [PMID: 27698376 PMCID: PMC5048190 DOI: 10.1038/srep34692] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 09/19/2016] [Indexed: 12/28/2022] Open
Abstract
Pinelliae Rhizoma (PR) is a commonly used Chinese medicinal herb, but it has been frequently reported about its toxicity. According to the traditional Chinese medicine theory, processing can reduce the toxicity of the herbs. Here, we aim to determine if processing reduces the toxicity of raw PR, and to explore the underlying mechanisms of raw PR-induced toxicities and the toxicity-reducing effect of processing. Biochemical and histopathological approaches were used to evaluate the toxicities of raw and processed PR. Rat serum metabolites were analyzed by LC-TOF-MS. Ingenuity pathway analysis of the metabolomics data highlighted the biological pathways and network functions involved in raw PR-induced toxicities and the toxicity-reducing effect of processing, which were verified by molecular approaches. Results showed that raw PR caused cardiotoxicity, and processing reduced the toxicity. Inhibition of mTOR signaling and activation of the TGF-β pathway contributed to raw PR-induced cardiotoxicity, and free radical scavenging might be responsible for the toxicity-reducing effect of processing. Our data shed new light on the mechanisms of raw PR-induced cardiotoxicity and the toxicity-reducing effect of processing. This study provides scientific justifications for the traditional processing theory of PR, and should help in optimizing the processing protocol and clinical combinational application of PR.
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Affiliation(s)
- Tao Su
- Consun Chinese Medicines Research Centre for Renal Diseases, School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
| | - Yong Tan
- Institute of Basic Research in Clinical Medicine, China Academy of Chinese Medical Science, Beijing, China
| | - Man-Shan Tsui
- Department of Pathology, Caritas Medical Center, Hong Kong, China
| | - Hua Yi
- Department of Pathology, Guangzhou University of Chinese Medicine, China
| | - Xiu-Qiong Fu
- Consun Chinese Medicines Research Centre for Renal Diseases, School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
| | - Ting Li
- Consun Chinese Medicines Research Centre for Renal Diseases, School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
| | - Chi Leung Chan
- Consun Chinese Medicines Research Centre for Renal Diseases, School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
| | - Hui Guo
- Consun Chinese Medicines Research Centre for Renal Diseases, School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
| | - Ya-Xi Li
- Consun Chinese Medicines Research Centre for Renal Diseases, School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
| | - Pei-Li Zhu
- Consun Chinese Medicines Research Centre for Renal Diseases, School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
| | - Anfernee Kai Wing Tse
- Consun Chinese Medicines Research Centre for Renal Diseases, School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
- Institute of Integrated Bioinfomedicine & Translational Science, HKBU Shenzhen Research Institute and Continuing Education, Shenzhen, China
| | - Hui Cao
- College of Pharmacy, Jinan University, Guangzhou, China
| | - Ai-Ping Lu
- Consun Chinese Medicines Research Centre for Renal Diseases, School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
- Institute of Integrated Bioinfomedicine & Translational Science, HKBU Shenzhen Research Institute and Continuing Education, Shenzhen, China
| | - Zhi-Ling Yu
- Consun Chinese Medicines Research Centre for Renal Diseases, School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
- Institute of Integrated Bioinfomedicine & Translational Science, HKBU Shenzhen Research Institute and Continuing Education, Shenzhen, China
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Filser JG, Artati A, Li Q, Pütz C, Semder B, Klein D, Kessler W. Novel and existing data for a future physiological toxicokinetic model of ethylene and its metabolite ethylene oxide in mouse, rat, and human. Chem Biol Interact 2015; 241:76-86. [DOI: 10.1016/j.cbi.2015.04.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Filser JG, Kessler W, Artati A, Erbach E, Faller T, Kreuzer PE, Li Q, Lichtmannegger J, Numtip W, Klein D, Pütz C, Semder B, Csanády GA. Ethylene oxide in blood of ethylene-exposed B6C3F1 mice, Fischer 344 rats, and humans. Toxicol Sci 2013; 136:344-58. [PMID: 24068676 PMCID: PMC3858200 DOI: 10.1093/toxsci/kft218] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 09/09/2013] [Indexed: 02/04/2023] Open
Abstract
The gaseous olefin ethylene (ET) is metabolized in mammals to the carcinogenic epoxide ethylene oxide (EO). Although ET is the largest volume organic chemical worldwide, the EO burden in ET-exposed humans is still uncertain, and only limited data are available on the EO burden in ET-exposed rodents. Therefore, EO was quantified in blood of mice, rats, or 4 volunteers that were exposed once to constant atmospheric ET concentrations of between 1 and 10 000 ppm (rodents) or 5 and 50 ppm (humans). Both the compounds were determined by gas chromatography. At ET concentrations of between 1 and 10 000 ppm, areas under the concentration-time curves of EO in blood (µmol × h/l) ranged from 0.039 to 3.62 in mice and from 0.086 to 11.6 in rats. At ET concentrations ≤ 30 ppm, EO concentrations in blood were 8.7-fold higher in rats and 3.9-fold higher in mice than that in the volunteer with the highest EO burdens. Based on measured EO concentrations, levels of EO adducts to hemoglobin and lymphocyte DNA were calculated for diverse ET concentrations and compared with published adduct levels. For given ET exposure concentrations, there were good agreements between calculated and measured levels of adducts to hemoglobin in rats and humans and to DNA in rats and mice. Reported hemoglobin adduct levels in mice were higher than calculated ones. Furthermore, information is given on species-specific background adduct levels. In summary, the study provides most relevant data for an improved assessment of the human health risk from exposure to ET.
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Affiliation(s)
- Johannes Georg Filser
- *Institute of Molecular Toxicology and Pharmacology, Helmholtz Zentrum München, 85764 Neuherberg, Germany; and
- †Institut für Toxikologie und Umwelthygiene, Technische Universität München, München, Germany
| | - Winfried Kessler
- *Institute of Molecular Toxicology and Pharmacology, Helmholtz Zentrum München, 85764 Neuherberg, Germany; and
| | - Anna Artati
- *Institute of Molecular Toxicology and Pharmacology, Helmholtz Zentrum München, 85764 Neuherberg, Germany; and
| | - Eva Erbach
- *Institute of Molecular Toxicology and Pharmacology, Helmholtz Zentrum München, 85764 Neuherberg, Germany; and
| | - Thomas Faller
- *Institute of Molecular Toxicology and Pharmacology, Helmholtz Zentrum München, 85764 Neuherberg, Germany; and
| | - Paul Erich Kreuzer
- *Institute of Molecular Toxicology and Pharmacology, Helmholtz Zentrum München, 85764 Neuherberg, Germany; and
| | - Qiang Li
- *Institute of Molecular Toxicology and Pharmacology, Helmholtz Zentrum München, 85764 Neuherberg, Germany; and
| | - Josef Lichtmannegger
- *Institute of Molecular Toxicology and Pharmacology, Helmholtz Zentrum München, 85764 Neuherberg, Germany; and
| | - Wanwiwa Numtip
- *Institute of Molecular Toxicology and Pharmacology, Helmholtz Zentrum München, 85764 Neuherberg, Germany; and
| | - Dominik Klein
- *Institute of Molecular Toxicology and Pharmacology, Helmholtz Zentrum München, 85764 Neuherberg, Germany; and
- †Institut für Toxikologie und Umwelthygiene, Technische Universität München, München, Germany
| | - Christian Pütz
- *Institute of Molecular Toxicology and Pharmacology, Helmholtz Zentrum München, 85764 Neuherberg, Germany; and
| | - Brigitte Semder
- *Institute of Molecular Toxicology and Pharmacology, Helmholtz Zentrum München, 85764 Neuherberg, Germany; and
| | - György András Csanády
- *Institute of Molecular Toxicology and Pharmacology, Helmholtz Zentrum München, 85764 Neuherberg, Germany; and
- †Institut für Toxikologie und Umwelthygiene, Technische Universität München, München, Germany
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Li Q, Csanády GA, Kessler W, Klein D, Pankratz H, Pütz C, Richter N, Filser JG. Kinetics of ethylene and ethylene oxide in subcellular fractions of lungs and livers of male B6C3F1 mice and male fischer 344 rats and of human livers. Toxicol Sci 2011; 123:384-98. [PMID: 21785163 PMCID: PMC3179684 DOI: 10.1093/toxsci/kfr194] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Accepted: 07/13/2011] [Indexed: 12/01/2022] Open
Abstract
Ethylene (ET) is metabolized in mammals to the carcinogenic ethylene oxide (EO). Although both gases are of high industrial relevance, only limited data exist on the toxicokinetics of ET in mice and of EO in humans. Metabolism of ET is related to cytochrome P450-dependent mono-oxygenase (CYP) and of EO to epoxide hydrolase (EH) and glutathione S-transferase (GST). Kinetics of ET metabolism to EO and of elimination of EO were investigated in headspace vessels containing incubations of subcellular fractions of mouse, rat, or human liver or of mouse or rat lung. CYP-associated metabolism of ET and GST-related metabolism of EO were found in microsomes and cytosol, respectively, of each species. EH-related metabolism of EO was not detectable in hepatic microsomes of rats and mice but obeyed saturation kinetics in hepatic microsomes of humans. In ET-exposed liver microsomes, metabolism of ET to EO followed Michaelis-Menten-like kinetics. Mean values of V(max) [nmol/(min·mg protein)] and of the apparent Michaelis constant (K(m) [mmol/l ET in microsomal suspension]) were 0.567 and 0.0093 (mouse), 0.401 and 0.031 (rat), and 0.219 and 0.013 (human). In lung microsomes, V(max) values were 0.073 (mouse) and 0.055 (rat). During ET exposure, the rate of EO production decreased rapidly. By modeling a suicide inhibition mechanism, rate constants for CYP-mediated catalysis and CYP inactivation were estimated. In liver cytosol, mean GST activities to EO expressed as V(max)/K(m) [μl/(min·mg protein)] were 27.90 (mouse), 5.30 (rat), and 1.14 (human). The parameters are most relevant for reducing uncertainties in the risk assessment of ET and EO.
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Affiliation(s)
- Qiang Li
- Institute of Toxicology, German Research Center for Environmental Health, Helmholtz Zentrum München, D-85764 Neuherberg, Germany
- Institut für Toxikologie und Umwelthygiene, Technische Universität München, D-80802 München, Germany
| | - György András Csanády
- Institute of Toxicology, German Research Center for Environmental Health, Helmholtz Zentrum München, D-85764 Neuherberg, Germany
- Institut für Toxikologie und Umwelthygiene, Technische Universität München, D-80802 München, Germany
| | - Winfried Kessler
- Institute of Toxicology, German Research Center for Environmental Health, Helmholtz Zentrum München, D-85764 Neuherberg, Germany
| | - Dominik Klein
- Institute of Toxicology, German Research Center for Environmental Health, Helmholtz Zentrum München, D-85764 Neuherberg, Germany
- Institut für Toxikologie und Umwelthygiene, Technische Universität München, D-80802 München, Germany
| | - Helmut Pankratz
- Institut für Rechtsmedizin, Ludwig-Maximilians-Universität München, D-80336 München, Germany
| | - Christian Pütz
- Institute of Toxicology, German Research Center for Environmental Health, Helmholtz Zentrum München, D-85764 Neuherberg, Germany
| | - Nadine Richter
- Institute of Toxicology, German Research Center for Environmental Health, Helmholtz Zentrum München, D-85764 Neuherberg, Germany
- Institut für Toxikologie und Umwelthygiene, Technische Universität München, D-80802 München, Germany
| | - Johannes Georg Filser
- Institute of Toxicology, German Research Center for Environmental Health, Helmholtz Zentrum München, D-85764 Neuherberg, Germany
- Institut für Toxikologie und Umwelthygiene, Technische Universität München, D-80802 München, Germany
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Halliwell B, Grootveld M, Gutteridge JM. Methods for the measurement of hydroxyl radicals in biomedical systems: deoxyribose degradation and aromatic hydroxylation. METHODS OF BIOCHEMICAL ANALYSIS 2006; 33:59-90. [PMID: 2833681 DOI: 10.1002/9780470110546.ch2] [Citation(s) in RCA: 161] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Cooper AJL. The role of glutamine transaminase K (GTK) in sulfur and alpha-keto acid metabolism in the brain, and in the possible bioactivation of neurotoxicants. Neurochem Int 2004; 44:557-77. [PMID: 15016471 DOI: 10.1016/j.neuint.2003.12.002] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Glutamine transaminase K (GTK), which is a freely reversible glutamine (methionine) aromatic amino acid aminotransferase, is present in most mammalian tissues, including brain. Quantitatively, the most important amine donor in vivo is glutamine. The product of glutamine transamination (i.e., alpha-ketoglutaramate; alphaKGM) is rapidly removed by cyclization and/or conversion to alpha-ketoglutarate. Transamination is therefore "pulled" in the direction of glutamine utilization. Major biological roles of GTK are to maintain low levels of phenylpyruvate and to close the methionine salvage pathway. GTK also catalyzes the transamination of cystathionine, lanthionine, and thialysine to the corresponding alpha-keto acids, which cyclize to ketimines. The cyclic ketimines and several metabolites derived therefrom are found in brain. It is not clear whether these compounds have a biological function or are metabolic dead-ends. However, high-affinity binding of lanthionine ketimine (LK) to brain membranes has been reported. Mammalian tissues possess several enzymes capable of catalyzing transamination of kynurenine in vitro. Two of these kynurenine aminotransferases (KATs), namely KAT I and KAT II, are present in brain and have been extensively studied. KAT I and KAT II are identical to GTK and alpha-aminoadipate aminotransferase, respectively. GTK/KAT I is largely cytosolic in kidney, but mostly mitochondrial in brain. The same gene codes for both forms, but alternative splicing dictates whether a 32-amino acid mitochondrial-targeting sequence is present in the expressed protein. The activity of KAT I is altered by a missense mutation (E61G) in the spontaneously hypertensive rat. The symptoms may be due in part to alteration of kynurenine transamination. However, owing to strong competition from other amino acid substrates, the turnover of kynurenine to kynurenate by GTK/KAT I in nervous tissue must be slow unless kynurenine and GTK are sequestered in a compartment distinct from the major amino acid pools. The possibility is discussed that the spontaneous hypertension in rats carrying the GTK/KAT I mutation may be due in part to disruption of glutamine transamination. GTK is one of several pyridoxal 5'-phosphate (PLP)-containing enzymes that can catalyze non-physiological beta-elimination reactions with cysteine S-conjugates containing a good leaving group attached at the sulfur. These elimination reactions may contribute to the bioactivation of certain electrophiles, resulting in toxicity to kidney, liver, brain, and possibly other organs. On the other hand, the beta-lyase reaction catalyzed by GTK may be useful in the conversion of some cysteine S-conjugate prodrugs to active components in vivo. The roles of GTK in (a) brain nitrogen, sulfur, and aromatic amino acid/kynurenine metabolism, (b) brain alpha-keto acid metabolism, (c) bioactivation of certain electrophiles in brain, (d) prodrug targeting, and (e) maintenance of normal blood pressure deserve further study.
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Affiliation(s)
- Arthur J L Cooper
- Department of Biochemistry, Weill Medical College of Cornell University, Burke Medical Research Institute, 785 Mamaroneck Avenue, White Plains, NY 10605, USA.
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Strolin-Benedetti M, Brogin G, Bani M, Oesch F, Hengstler JG. Association of cytochrome P450 induction with oxidative stress in vivo as evidenced by 3-hydroxylation of salicylate. Xenobiotica 1999; 29:1171-80. [PMID: 10598750 DOI: 10.1080/004982599238038] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
1. Previous studies have shown that formation of 2,3-dihydroxybenzoate (2,3-DHB) from salicylate in vivo is a sensitive and specific marker of *OH radical generation, since 2,3-DHB is formed exclusively by *OH radicals, whereas both *OH radicals and cytochrome P450 (CYP) contribute to the production of 2,5-DHB. In the present study the salicylate-hydroxylation assay was used to examine whether CYP induction by the administration of dexamethasone, phenobarbital or beta-naphthoflavone to the male rat led to oxidative stress in vivo. 2. Dexamethasone was used under conditions that induced an approximately 50-fold induction of CYP P4503A expression in liver microsomal protein. Treatment with dexamethasone caused a 17.2-fold increase in 2,3-DHB plasma concentration compared with control animals. An increase in total hydroxylated salicylate (2,3-DHB plus 2,5-DHB) of 133.5 micromol/l plasma was produced, of which--assuming that the attack by *OH in position 3 or 5 of salicylate occurs at a similar rate--10.9 micromol/l were due to *OH radical attack and 122.6 micromol/l due to metabolism by CYP. 3. Phenobarbital led to a 4.7-fold increase in 2,3-DHB plasma concentration under conditions that induced CYP P4502B and 3A. An increase in total hydroxylated salicylate of 34.3 micromol/l plasma was observed, 2.0 micromol/l due to *OH radical attack and 32.3 micromol/l due to metabolism by cytochrome P450. 4. In contrast to dexamethasone and phenobarbital, beta-naphthoflavone did not cause a significant increase in 2,3-DHB plasma concentrations. 5. SKF 525A, a mixed-function oxidase inhibitor, caused a significant reduction of mean 2,5-DHB plasma concentration by 35% (p < 0.001), whereas 2,3-DHB was not significantly reduced, indicating that in contrast to the situation after induction by dexamethasone or phenobarbital, *OH radical generation by constitutive CYP contributes only to a minor degree to total in vivo *OH radical generation. 6. This study shows for the first time, to the authors' knowledge, that induction of some (but not all) P450s is associated with the production of hydroxyl radicals in vivo.
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Abstract
The discovery in 1983 of fungal "ligninases" capable of catalyzing the peroxidation of nonphenolic aromatic lignin components has been seen as a major advance in understanding how certain basidiomycete fungi can completely degrade lignin. The ability of these lignin-type peroxidases to covert millimolar concentrations of veratryl alcohol to veratraldehyde, indicated by a change in the A310 of veratraldehyde, has become the standard assay for routine quantitation of LP activity. A new assay based on the oxidation of micromolar concentrations of the dye Azure B is presented. Although it is as simple and rapid as the veratryl alcohol assay, it appears to overcome some of the shortcomings of that assay. In particular, interference from UV- and short-wavelength visible-light-absorbing materials is greatly reduced and assay specificity is improved.
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Affiliation(s)
- F S Archibald
- Pulp and Paper Research Institute of Canada, Pointe Claire, Quebec
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Archibald FS. Lignin Peroxidase Activity Is Not Important in Biological Bleaching and Delignification of Unbleached Kraft Pulp by
Trametes versicolor. Appl Environ Microbiol 1992; 58:3101-9. [PMID: 16348775 PMCID: PMC183055 DOI: 10.1128/aem.58.9.3101-3109.1992] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The discovery in 1983 of fungal lignin peroxidases able to catalyze the oxidation of nonphenolic aromatic lignin model compounds and release some CO
2
from lignin has been seen as a major advance in understanding how fungi degrade lignin. Recently, the fungus
Trametes versicolor
was shown to be capable of substantial decolorization and delignification of unbleached industrial kraft pulps over 2 to 5 days. The role, if any, of lignin peroxidase in this biobleaching was therefore examined. Several different assays indicated that
T. versicolor
can produce and secrete peroxidase proteins, but only under certain culture conditions. However, work employing a new lignin peroxidase inhibitor (metavanadate ions) and a new lignin peroxidase assay using the dye azure B indicated that secreted lignin peroxidases do not play a role in the
T. versicolor
pulp-bleaching system. Oxidative activity capable of degrading 2-keto-4-methiolbutyric acid (KMB) appeared unique to ligninolytic fungi and always accompanied pulp biobleaching.
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Affiliation(s)
- F S Archibald
- Pulp and Paper Research Institute of Canada, 570 St. John's Boulevard, Pointe Claire, Quebec, Canada H9R 3J9
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GALEY JB, MILLECAMPS F, NGUYEN QL. Ethylene formation from methionine as a method to evaluate oxygen free radical scavenging and metal inactivation by cosmetics. Int J Cosmet Sci 1991; 13:65-78. [DOI: 10.1111/j.1467-2494.1991.tb00550.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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13
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Kang JO, Slivka A, Slater G, Cohen G. In vivo formation of hydroxyl radicals following intragastric administration of ferrous salt in rats. J Inorg Biochem 1989; 35:55-69. [PMID: 2540265 DOI: 10.1016/0162-0134(89)84005-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Accidental poisoning by oral iron preparations is a serious problem in young children. We investigated the formation of hydroxyl radicals (.OH) in rats after intragastric instillation of ferrous sulfate. .OH was detected via its reaction with intragastrically administered 2-keto-4-methylthiobutyrate to generate ethylene gas. Ascorbic acid is typically present in oral iron preparations in order to facilitate absorption by maintaining iron in the reduced state. However, ascorbate possesses two properties that can affect .OH, recycling of oxidized iron to the ferrous state augments .OH production, while ascorbate in high concentration scavenges .OH. In experiments conducted in vitro, both actions were evident, depending upon the concentration of ascorbate. In parallel experiments conducted in vivo, the scavenging action of ascorbate was more prominent. Experiments in vitro with .OH-scavengers (dimethylsulfoxide, ethanol) and with the enzyme, catalase, confirmed both the presence of .OH and its dependence upon generated hydrogen peroxide during the oxidation of ferrous salt by molecular oxygen. Hydroxyl radicals (and/or reactive higher oxidation states of iron) may play a role in tissue damage after accidental overdose of oral iron.
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Affiliation(s)
- J O Kang
- Department of Neurology, Graduate School of Biomedical Sciences, Mount Sinai School of Medicine, New York, NY 10029
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Halliwell B, Grootveld M. The measurement of free radical reactions in humans. Some thoughts for future experimentation. FEBS Lett 1987; 213:9-14. [PMID: 3030811 DOI: 10.1016/0014-5793(87)81455-2] [Citation(s) in RCA: 246] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The question as to whether free radical reactions are a major cause of tissue injury in human disease, or merely an accompaniment to such injury, is very difficult to answer because of lack of adequate experimental techniques. New techniques that are becoming available are discussed, with specific reference to their use in humans.
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Grootveld M, Halliwell B. Aromatic hydroxylation as a potential measure of hydroxyl-radical formation in vivo. Identification of hydroxylated derivatives of salicylate in human body fluids. Biochem J 1986; 237:499-504. [PMID: 3026319 PMCID: PMC1147012 DOI: 10.1042/bj2370499] [Citation(s) in RCA: 319] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Attack by .OH radicals, generated by a Fenton system, upon salicylate produces 2,3-dihydroxybenzoate and 2,5-dihydroxybenzoate as major products and catechol as a minor product. H.p.l.c. separation combined with electrochemical detection was used to identify and quantify 2,3-dihydroxybenzoate and 2,5-dihydroxybenzoate in human plasma and synovial fluid. We propose that conversion of salicylate into 2,3-dihydroxybenzoate, or of other aromatic compounds into specific hydroxylated products, may be a useful assay for .OH formation in the human body.
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