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Corami F, Capodaglio G, Turetta C, Bragadin M, Calace N, Petronio BM. Complexation of Cadmium and Copper by Fluvial Humic Matter and Effects on Their Toxicity. ACTA ACUST UNITED AC 2007; 97:25-37. [PMID: 17822261 DOI: 10.1002/adic.200690083] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The effects of humic acids and fulvic acids isolated from the River Arno (Italy) on the bioavailability and toxicity of cadmium and copper were assessed in relation to changes in their speciation. Measurements of the complexing capacity of solutions containing these organic ligands were carried out by a titration procedure followed by DPASV and toxicity tests were carried out using lysosomes isolated from rat liver. The complexing capacity of the physiological medium containing about 13 mg/L of humic acids, expressed as ligand concentrations, was 0.30 and 0.072 micromol/L for cadmium and copper respectively; the corresponding conditional stability constants were 4.2 x 10(11) and 1.3 x 10(8) (mol/L)-1. The complexing capacities of the solution containing the same amount of fulvic acids were 0.33 and 0.164 micromol/L for cadmium and copper respectively, the conditional stability constants were 3.2 x 10(11) and 2.4 x 10(7) (mol/L)-1. The humic acids reduced the toxicity of cadmium by about 5 times: the EC50 changed from 4.4 to 20.4 micromol/L. The dose effect curve of copper presented a bi-sigmoid trend and two EC50 values can be determined: The EC50(1) in the presence of humic acids changed from 2.0 to 3.1 micromol/L, while the EC50(2) increased from 22.3 to 45.3 micromol/L. The fulvic acids reduced the cadmium toxicity by about the same amount as humic acids, from 4.4 to 18.6 micromol/L, but they had no effect on copper toxicity. Analysing the chemical speciation of cadmium and copper in the presence of humic components and under toxicity test conditions we can say that the appreciable decrease of EC50 is not related to changes in their speciation; we can hypothesize that this is due to different processes, as well as to blocking of the lysosomal membrane. On the basis of the shape of the dose-effect curves obtained for cadmium and copper respectively, we can say that the toxic effects of the two metals are different and we can hypothesize that copper could exercise its toxic activity by inhibiting the ATP-driven proton pump and the function of the Cl- selective channel.
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Affiliation(s)
- F Corami
- Dipartimento di Scienze Ambientali, Università Ca' Foscari, Venezia
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Buck-Koehntop BA, Porcelli F, Lewin JL, Cramer CJ, Veglia G. Biological chemistry of organotin compounds: Interactions and dealkylation by dithiols. J Organomet Chem 2006. [DOI: 10.1016/j.jorganchem.2005.12.047] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Watling-Payne AS, Selwyn MJ. Decrease of proton permeability of CF1-deficient chloroplast particles by triphenyltin. FEBS Lett 2001. [DOI: 10.1016/0014-5793(75)80225-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Surdy P, Rubini P, Buzás N, Henry B, Pellerito L, Gajda T. Interaction of Dimethyltin(IV)2+ Cation with Gly-Gly, Gly-His, and Some Related Ligands. A New Case of a Metal Ion Able To Promote Peptide Nitrogen Deprotonation in Aqueous Solution. Inorg Chem 1999. [DOI: 10.1021/ic980398o] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Péter Surdy
- Department of Inorganic and Analytical Chemistry, A. József University, 6701 Szeged, P.O. Box 440, Hungary, Laboratoire de Chimie Physique Organique et Colloidale, UMR SRSMC CNRS No. 7565, Université Henri PoincaréNancy I, B.P. 239, F-54506 Vandoeuvre-lès-Nancy Cedex, France, Research Group on Biocoordination Chemistry of the Hungarian Academy of Sciences, A. József University, 6701 Szeged, P.O. Box 440, Hungary, and Department of Inorganic Chemistry, University of Palermo, Palermo, Italy
| | - Patrice Rubini
- Department of Inorganic and Analytical Chemistry, A. József University, 6701 Szeged, P.O. Box 440, Hungary, Laboratoire de Chimie Physique Organique et Colloidale, UMR SRSMC CNRS No. 7565, Université Henri PoincaréNancy I, B.P. 239, F-54506 Vandoeuvre-lès-Nancy Cedex, France, Research Group on Biocoordination Chemistry of the Hungarian Academy of Sciences, A. József University, 6701 Szeged, P.O. Box 440, Hungary, and Department of Inorganic Chemistry, University of Palermo, Palermo, Italy
| | - Norbert Buzás
- Department of Inorganic and Analytical Chemistry, A. József University, 6701 Szeged, P.O. Box 440, Hungary, Laboratoire de Chimie Physique Organique et Colloidale, UMR SRSMC CNRS No. 7565, Université Henri PoincaréNancy I, B.P. 239, F-54506 Vandoeuvre-lès-Nancy Cedex, France, Research Group on Biocoordination Chemistry of the Hungarian Academy of Sciences, A. József University, 6701 Szeged, P.O. Box 440, Hungary, and Department of Inorganic Chemistry, University of Palermo, Palermo, Italy
| | - Bernard Henry
- Department of Inorganic and Analytical Chemistry, A. József University, 6701 Szeged, P.O. Box 440, Hungary, Laboratoire de Chimie Physique Organique et Colloidale, UMR SRSMC CNRS No. 7565, Université Henri PoincaréNancy I, B.P. 239, F-54506 Vandoeuvre-lès-Nancy Cedex, France, Research Group on Biocoordination Chemistry of the Hungarian Academy of Sciences, A. József University, 6701 Szeged, P.O. Box 440, Hungary, and Department of Inorganic Chemistry, University of Palermo, Palermo, Italy
| | - Lorenzo Pellerito
- Department of Inorganic and Analytical Chemistry, A. József University, 6701 Szeged, P.O. Box 440, Hungary, Laboratoire de Chimie Physique Organique et Colloidale, UMR SRSMC CNRS No. 7565, Université Henri PoincaréNancy I, B.P. 239, F-54506 Vandoeuvre-lès-Nancy Cedex, France, Research Group on Biocoordination Chemistry of the Hungarian Academy of Sciences, A. József University, 6701 Szeged, P.O. Box 440, Hungary, and Department of Inorganic Chemistry, University of Palermo, Palermo, Italy
| | - Tamás Gajda
- Department of Inorganic and Analytical Chemistry, A. József University, 6701 Szeged, P.O. Box 440, Hungary, Laboratoire de Chimie Physique Organique et Colloidale, UMR SRSMC CNRS No. 7565, Université Henri PoincaréNancy I, B.P. 239, F-54506 Vandoeuvre-lès-Nancy Cedex, France, Research Group on Biocoordination Chemistry of the Hungarian Academy of Sciences, A. József University, 6701 Szeged, P.O. Box 440, Hungary, and Department of Inorganic Chemistry, University of Palermo, Palermo, Italy
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A proposal for a new mechanism of interaction of trialkyltin (TAT) compounds with mitochondria. J Inorg Biochem 1997. [DOI: 10.1016/s0162-0134(97)00011-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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7
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Hg2+ and Cu+ are ionophores, mediating Cl-/OH- exchange in liposomes and rabbit renal brush border membranes. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)41764-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Harrison PG, Sharpe NW. Model studies of trialkyltin-protein interactions:13C NMR analysis of solution equilibria of the complex between trimethyltin and methylN-benzoyl-l-leucyl-l-histidinate. Appl Organomet Chem 1989. [DOI: 10.1002/aoc.590030205] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Connerton IF, Griffiths DE. Organotin compounds as energy-potentiated uncouplers of rat liver mitochondria. Appl Organomet Chem 1989. [DOI: 10.1002/aoc.590030611] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Chandra S, Polya GM, James BD, Magee RJ. Inhibition of oxidative phosphorylation by organotin thiocarbamates. Chem Biol Interact 1989; 71:21-36. [PMID: 2776232 DOI: 10.1016/0009-2797(89)90088-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A series of triphenyl-, tricyclohexyl- and tribenzyltin compounds have been synthesized and examined as inhibitors of mitochondrial oxidative phosphorylation. All compounds tested inhibit oxidative phosphorylation linked to succinate oxidation by potato tuber mitochondria. All of the organotin compounds inhibit ADP-stimulated O2 uptake linked to succinate oxidation with concentrations for 50% inhibition in the range 2-50 microM. This inhibition is not due to inhibition of electron transport from succinate to O2 per se: none of the organotin compounds at 50 microM substantially inhibit the rate of succinate oxidation in the presence of 2,4-dinitrophenol. Representative organotin compounds at 0.5-50 microM do not act as uncouplers of succinate oxidation. It is concluded that the organotin compounds act as energy transfer inhibitors to inhibit oxidative phosphorylation in potato tuber mitochondria. A similar mode of action of representative organotin compounds was found with rat liver mitochondria. These organotin compounds inhibit a hydrophobic Ca2+-dependent plant protein kinase in the absence but not in the presence of thiols.
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Affiliation(s)
- S Chandra
- Department of Chemistry, La Trobe University, Bundoora, Victoria, Australia
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Mitchell P. A new redox loop formality involving metal-catalysed hydroxide-ion translocation. A hypothetical Cu loop mechanism for cytochrome oxidase. FEBS Lett 1987; 222:235-45. [PMID: 2820802 DOI: 10.1016/0014-5793(87)80378-2] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A new hypothetical type of redox loop is described, which translocates hydroxide instead of protons. Conventional protonmotive redox loops use carriers of protons with electrons (e.g. QH2/Q systems) to couple electron transfer to the translocation of protons. The putative hydroxidemotive redox loop uses carriers of hydroxide ions against electrons (e.g. transition-metal centres) to couple electron transfer to the translocation of hydroxide ions. This simple idea leads to the proposal of a hydroxidemotive Cu loop mechanism that may possibly be applicable to the CuA or CuB centre of cytochrome oxidase, and might thus account for the coupling of electron transfer to net proton translocation in that osmoenzyme.
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Affiliation(s)
- P Mitchell
- Glynn Research Institute, Bodmin, England
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Harrison PG, Sharpe NW. Complexes of terminally-protected dipeptides with trimethyltin as models for triorganotin-protein interactions. Inorganica Chim Acta 1985. [DOI: 10.1016/s0020-1693(00)84315-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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13
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Webber RJ, Dollins SC, Harris M, Hough AJ. Effect of alkyltins on rabbit articular and growth-plate chondrocytes in monolayer culture. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH 1985; 16:229-42. [PMID: 4078933 DOI: 10.1080/15287398509530736] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The effect of four different alkyltins (trimethyltin, triethyltin, dibutyltin, and dioctyltin) on the metabolism of rabbit articular and growth-plate chondrocytes was investigated using a monolayer cell-culture system. In most instances the compounds tested exhibited a general cytotoxic effect on these cells, inhibiting the synthesis of both DNA and sulfated proteoglycans. The effect of these compounds on proteoglycan synthesis was both quantitative and qualitative, as demonstrated by CsCl isopycnic density gradient centrifugation and gel exclusion chromatographic techniques. However, certain tin compounds tested, at specific concentrations, exerted a stimulatory effect on chondrocyte proliferation. Regarding DNA synthesis, growth-plate chondrocytes were more sensitive to the effect of the triethyltin, dibutyltin, and dioctyltin than were articular chondrocytes. The data are discussed in relation to the possible effects of the alkyltins on skeletal growth and development as well as the mechanism of action of the alkyltins at the molecular level.
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Passarella S, Marra E, Doonan S, Languino LR, Saccone C, Quagliariello E. Uptake of aspartate aminotransferase into mitochondria in vitro depends on the transmembrane pH gradient. Biochem J 1982; 202:353-62. [PMID: 7092821 PMCID: PMC1158118 DOI: 10.1042/bj2020353] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
1. The effects of various inhibitors of electron transport and of oxidative phosphorylation and the effects of ionophores on the uptake of native aspartate aminotransferase into mitochondria were investigated. 2. Both antimycin and cyanide completely inhibited the uptake of the enzyme. On the other hand, uptake was stimulated to ATP and by oligomycin; however, the stimulation by ATP is inhibited by oligomycin. 3. The effects of ionophores of the valinomycin type in media containing K+ ions depended on the conditions used. Valinomycin alone stimulated the uptake of the enzyme, but in the presence of phosphate ions uptake was abolished. Nonactin was without effect at a low K+ concentration, but was stimulatory at 100 mM-KCl. Gramicidin also stimulated the uptake process. 4. Nigericin completely abolished uptake of aspartate aminotransferase into mitochondria. 5. The uptake of te enzyme was decreased by 18% in the absence of inhibitors or ionophores when the external pH was increased from 6.9 to 7.6. 6. These results indicate that ATP is not directly involved in the uptake of aspartate aminotransferase into mitochondria, neither is there a requirement for a cation gradient. Rather the uptake depends on the maintenance of a pH gradient across the mitochondrial inner membrane.
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Dawson AP, Farrow BG, Selwyn MJ. Studies on the nature of the high-affinity trialkyltin binding site of rat liver mitochondria. Biochem J 1982; 202:163-9. [PMID: 7082305 PMCID: PMC1158086 DOI: 10.1042/bj2020163] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
1. The proteolipid fraction isolated from rat liver mitochondria pretreated with [3H]triphenyltin chloride is enriched in triphenyltin compared with the original mitochondria. 2. Part of this [3H]triphenyltin is eluted with a protein of Mr 5000-6000 on Sephadex LH20 chromatography. 2. Mössbauer spectra of the proteolipid fraction treated with 119Sn-enriched triethyltin chloride show a doublet which corresponds closely with that assigned previously [Farrow & Dawson (1978) Eur. J. Biochem. 86. 85-95] to the absorption of triethyltin bound to the high-affinity binding site of the mitochondrial ATPase.
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16
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Moore AL, Linnett PE, Beechey RB. Dibutylchloromethyltin chloride, a potent inhibitor of electron transport in plant mitochondria. J Bioenerg Biomembr 1980; 12:309-23. [PMID: 7217044 DOI: 10.1007/bf00744691] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Dibutylchloromethyl tin chloride (DBCT) inhibits coupled and uncoupled respiration of mitochondria from potato tubers, cauliflower florets and etiolated mung bean hypocotyls with succinate and L-malate but not with external NADH or TMPD/ascorbate as substrates. Using potato and cauliflower mitochondria. DBCT at 200 pmole/mg of protein gives complete inhibition only in KCl-based media and at pH 6.8. DBCT has no effect on the internal pH of mung bean mitochondria, but does cause a decrease in the membrane potential. Electron transport through the alternative oxidase is not inhibited, neither is the ATP-synthase system. DBCT appears to interact with the functionally-distinct pool of ubiquinone associated with the oxidation of succinate and L-malate.
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Farrow BG, Dawson AP. Investigation of the interaction of triethyltin with rat liver mitochondria using binding studies and Mössbauer spectroscopy. EUROPEAN JOURNAL OF BIOCHEMISTRY 1978; 86:85-95. [PMID: 26563 DOI: 10.1111/j.1432-1033.1978.tb12287.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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19
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Haas D, Davidoff F. Magnesium-phenethylbiguanide competition in Mg2+-depleted hepatic mitochondria. Biochem Pharmacol 1978; 27:2263-7. [PMID: 728177 DOI: 10.1016/0006-2952(78)90086-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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20
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Huber SC, Edwards GE. Transport in C4 mesophyll chloroplasts characterization of the pyruvate carrier. BIOCHIMICA ET BIOPHYSICA ACTA 1977; 462:583-602. [PMID: 23150 DOI: 10.1016/0005-2728(77)90103-7] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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21
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Aldridge WN, Street BW, Skilleter DN. Oxidative phosphorylation. Halide-dependent and halide-independent effects of triorganotin and trioganolead compounds on mitochondrial functions. Biochem J 1977; 168:353-64. [PMID: 24436 PMCID: PMC1183780 DOI: 10.1042/bj1680353] [Citation(s) in RCA: 100] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
1. Each of five triorganotin and five triorganolead compounds was shown to perturb mithochondrial functions in three different ways. One is dependent and two are independent of Cl- in the medium. 2. Structure-activity relationships for the three interactions are described, and compounds suitable as tools for the separate study of each process are defined. 3. In a Cl- -containing medium trimethyltin, triethyltin, trimethyl-lead, triethyl-lead and tri-n-propyl-lead all produce the same maximum rate of ATP hydrolysis and O2 uptake; this rate is much less than that produced by uncoupling agents such as 2,4-dinitrophenol. 4. Increase in ATP hydrolysis and O2 uptake are measures on energy ultilization when triogranotin and triorganolead compounds bring about an exchange of external C1- for intramitochondrial OH- ions. Possible rate-limiting steps in this process are discussed. 5. In a C1- -containing medium ATP synthesis linked to the oxidation of beta-hydroxybutyrate or reduced cytochrone c is less inhibited by triethyltin or triethyl-lead than is ATP synthesis linked to the oxidation of succinate, pyruvate or L-glutamate. 6. The inhibition of ATP synthesis linked to the oxidation of both beta-hydroxybutyrate and reduced cytochrome c consists of two processes: one is a limited uncoupling and is C1- -dependent and the other is a C1- -independent inhibition of the energy-conservation system. 7. The different sensitivities to inhibition by triethyltin of mitochondrial functions involving the oxidation of beta-hydroxybutyrate and succinate are compared and discussed.
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Abstract
Triethyltin (TET) stimulated the basal respiration of Escherichia coli K-12 membrane vesicles in chloride (Cl-) medium but it had little effect on respiration in sulphate (SO4(2-)) medium. Since this uncoupling activity was Cl- dependent it was attributed to the Cl-/hydroxide (OH-) exchange reaction known to be mediated by TET [1,2]. TET inhibited the oxidation of succinate by intact E. coli in both Cl- and SO4(2-) medium, but at the same concentration of TET, inhibition was always more extensive in Cl- than SO4(2-) medium. In Cl- medium uncoupling in membrane vesicles and inhibition of succinate oxidation in intact bacteria occurred over the same concentration range and it appeared that the same mechanism, i.e. Cl-/OH- exchange, was responsible for both effects. Inhibition of succinate oxidation in SO4(2-) medium was not substantial until the concentration of TET was greater than 10(-5) M. Although the nature of this inhibition could not be determined by experiments with membrane vesicles indirect evidence from growth experiments indicated that it was due to impairment of oxidative phosphorylation. The relationship between these biochemical findings and the bacteriocidal action of TET was examined by using various concentrations of anion and substrate in the growth medium. Growth was inhibited in media containing either Cl- or SO4(2-) as the main anion but at a particular concentration of TET, inhibition was greater in Cl- medium. Growth was also inhibited to a greater extent in succinate than glucose medium. Furthermore in either Cl- or SO4(2-) glucose medium, lactic acid production increased as the concentration of TET was increased. These findings imply that the bacteriocidal action of TET is related to its effect(s) on oxidative phosphorylation.
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Cain K, Griffiths DE. Studies of energy-linked reactions. Localization of the site of action of trialkyltin in yeast mitochondria. Biochem J 1977; 162:575-80. [PMID: 141273 PMCID: PMC1164640 DOI: 10.1042/bj1620575] [Citation(s) in RCA: 75] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Ligand-binding studies with labelled triethyltin on yeast mitochondrial membranes showed the presence of high-affinity sites (KD = 0.6 micronM; 1.2 +/- 0.3 nmol/mg of protein) and low-affinity sites (KD less than 45 micronM; 70 +/- 20 nmol/mg of protein). The dissociation constant of the high-affinity site is in good agreement with the concentration of triethyltin required for inhibition of mitochondrial ATPase (adenosine triphosphatase) and oxidative phosphorylation. The high-affinity site is not competed for by oligomycin or venturicidin, indicating that triethyltin reacts at a different site from these inhibitors of oxidative phosphorylation. Fractionation of the mitochondrial membrane shows a specific association of the high-affinity sites with the ATP synthase complex. During purification of ATP synthase (oligomycin-sensitive ATPase) there is a 5-6-fold purification of oligomycin- and triethyltin-sensitive ATPase activity concomitant with a 7-9-fold increase in high-affinity triethyltin-binding sites. The purified yeast oligomycin-sensitive ATPase complex contains approximately six binding sites for triethyltin/mol of enzyme complex. It is concluded that specific triethyltin-binding sites are components of the ATP synthase complex, which accounts for the specific inhibition of ATPase and oxidative phosphorylation by triethyltin.
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Gatley SJ, Sherratt HS. The effects of diphenyleneiodonium and of 2,4-dichlorodiphenyleneiodonium on mitochondrial reactions. Mechanism of the inhibition of oxygen uptake as a consequence of the catalysis of the chloride/hydroxyl-ion exchange. Biochem J 1976; 158:317-26. [PMID: 10893 PMCID: PMC1163973 DOI: 10.1042/bj1580317] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
1. Increasing the substrate concentration only decreased the inhibition of mitochondrial oxidations by diphenyleneiodonium or by 2,4-dichlorophenyleneiodonium by a small amount. 2. Diphenyleneiodonium and 2,4-dichlorodiphenyleneiodonium lowered the amounts of succinate, citrate and glutamate accumulated in the matrix of mitochondria in the presence of Cl-, but not in its absences. 2,4-Dichlorodiphenyleneiodonium decreased the accumulation of substrates by mitochondria oxidizing glycerol 3-phosphate. 3. Diphenyleneiodonium caused an alkalinization of the medium with an anaerobic suspension of mitochondria, which was only partly reversed by Triton X-100. 4. The rate of proton extrusion by mitochondria oxidizing succinate was not altered by diphenyleneiodonium or by 2,4-dichlorodiphenyleneiodium, although the rate of decay of proton pulses was increased. 5. 2,4-Dichlorodiphenyleneiodonium shifted the pH optimum for succinate oxidation by intact mitochondria from pH 7.2 to 8.0, whereas there was no effect on that of freeze-thawed mitochondria, which was pH 8.0. 6. The concentration of 2,4-dichlorophenyleneiodonium required to inhibit respiration by 50% is less the higher the absolute rate of oxygen uptake. 7. EDTA, but not EGTA [ethanedioxybis(ethylamine)-tetra-acetic acid] increased the inhibition of respiration by diphenyleneiodonium, 2,4-dichlorodiphenyleneiodonium and by tri-n-propyltin. 8. It is concluded that diphenyleneiodonium and 2,4-dichlorodiphenyleneiodonium limit respiration in Cl--containing medium by causing an acidification of the matrix, and that there are pH-sensitive sites in the respiratory chain between NADH and succinate, and between succinate and cytochrome c.
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Barrett RH, Selwyn MJ. Effects of triphenylsulphonium ions on mitochondria. Inhibition of adenosine triphosphatase activity. Biochem J 1976; 156:315-22. [PMID: 133679 PMCID: PMC1163751 DOI: 10.1042/bj1560315] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Triphenylsulphonium ions inhibit mitochondrial oxidative phosphorylation and adenosine triphosphatase activity. The site of action is on the soluble F1 adenosine triphosphatase component. Triphenylsylphonium ions also inhibit electron transfer in the NAD-cytochrome b region of the respiratory chain. In both types of inhibition, triphenylsulphonium ions are effective at low concentrations, half-maximal inhibition being produced by a concentration of about 20-30 muM. These effects resemble the effects of alkylguanidines on mitochondria and are discussed in relation to the effects of alkylguanidines and other lipophilic cations such as ethidium and dibenzyldimethylammonium ions. A modification of the purification procedure for the soluble mitochondrial adenosine triphosphatase [Beechey, Hubbard, Linnett, Mitchell & Munn (1975) Biochem. J. 148, 533-537] IS DESCRIBED, WHICH YIELDS A PREPARATION WITH A HIGHER SPECIFIC ACTIVITY AND SHOWING FEWER BANDS IN GEL ELECTROPHORESIS.
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Skilleter DN. The influence of adenine nucleotides and oxidizable substrates on triethyltin-mediated chloride uptake by rat liver mitochondria in potassium chloride media. Biochem J 1976; 154:271-6. [PMID: 938451 PMCID: PMC1172707 DOI: 10.1042/bj1540271] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
In a 100 mM-KCl medium, pH 6.8, containing ATP increasing concentrations of triethyltin cause an uptake of Cl- into mitochondria with a maximum at 1 muM. This can be inhibited by atractylate or oligomycin, but is virtually unaffected by the presence of rotenone. When the medium contains substrate (pyruvate, beta-hydroxybutyrate or succinate), both in the presence and absence of adenine nucleotides, Cl- uptake is greater with a maximum at 1-10 muM-triethyltin. If substrate oxidation is blocked by respiratory-chain inhibitors the Cl- uptake mediated by triethyltin is inhibited except in the media containing ATP, when the characteristics of Cl- uptake similar to that found in the medium containing ATP alone are observed. Under all conditions tested Cl- uptake is decreased by the presence of 2,4-dinitrophenol. It is concluded that energy from either the oxidation of substrate or the hydrolysis of ATP is associated with the generation of sufficient OH- to enable the triethyltin-mediated Cl-/OH- exchange to occur under the metabolic conditions relevant to this action of triethyltin.
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Ariel N, Avi-Dor Y. Chloride-dependent restoration of coupling by oligomycin in rat liver mitochondria. Biochem J 1975; 152:115-9. [PMID: 55121 PMCID: PMC1172446 DOI: 10.1042/bj1520115] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In rat liver mitochondria suspended in KC1 medium, oligomycin interfered with the effect of uncouplers on energy conservation. It antagonized the effect of uncouplers that are weak acids (2,4-dinitrophenol etc.), but enhanced that of the lipid-penetrating cation NN-dimethyl-N'N'-dibenzylammonium. Oligomycin caused none of the above effects when Br- or NO-/3 was substituted for C1- as the major anionic species in the assay medium. The concentration of oligomycin that exerted the above-mentioned effects was lower than that necessary for the inhibition of energy transfer, but was in the range that induced C1- permeation through the cristae membrane. The possible connexion between the effect of oligomycin on C1- permeation and its interference with the action of uncouplers is discussed.
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Wulf RG, Byington KH. On the structure-activity relationships and mechanism of organotin induced, nonenergy dependent swelling of liver mitochondria. Arch Biochem Biophys 1975; 167:176-85. [PMID: 1130791 DOI: 10.1016/0003-9861(75)90454-3] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Skilleter DN. The decrease of mitochondrial substrate uptake caused by trialkyltin and trialkyl-lead compounds in chloride media and its relevance to inhibition of oxidative phosphorylation. Biochem J 1975; 146:465-71. [PMID: 808219 PMCID: PMC1165325 DOI: 10.1042/bj1460465] [Citation(s) in RCA: 40] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
1. In a 100 mM-KCl medium (pH 6.8) containing ATP, triethyltin (1 muM) causes a decrease in the uptake of pyruvate, malate, citrate or beta-hydroxybutyrate by rat liver mitochondria, but no decrease is observed in a 100 mM-KNO3 medium. This response is not modified by the presence of rotenone in the incubation medium. 2. In the KCl medium at least 1 muM-triethyltin is required to cause maximum inhibition of pyruvate uptake. 3. Trimethyltin, tributyltin and the trialkyl-lead analogues at 1 muM, to varying degrees, also cause a decrease in pyruvate uptake by mitochondria only in the KCl medium. 4. Triethyltin stimulates resting respiration of mitochondria with all the substrates tested in the KCl medium but not in the KNO3 medium, yet this stimulation of O2 uptake occurs under conditions when substrate uptake is decreased. 5. In contrast, both O2 uptake during state 3 respiration and ATP synthesis when linked to the oxidation of pyruvate, malate or citrate are strongly inhibited by 1 muM-triethyltin in a KCl medium, but O2 uptake and ATP synthesis during the oxidation of beta-hydroxybutyrate are only slightly affected. In a KNO3 medium O2 uptake and ATP synthesis linked to the oxidation of all substrates are only slightly affected. 6. The relevance of the decrease in substrate uptake by mitochondria caused by triethyltin in a KCl medium to the greater sensitivity of various mitochondrial functions observed in vitro is discussed. It is concluded that decrease of matrix substrate content is probably not the major cause of the greater sensitivity of oxidative phosphorylation to triethyltin in a KCl medium observed previously.
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Watling-Payne AS, Selwyn MJ. Inhibition and uncoupling of photophosphorylation in isolated chloroplasts by organotin, organomercury and diphenyleneiodonium compounds. Biochem J 1974; 142:65-74. [PMID: 4441373 PMCID: PMC1168211 DOI: 10.1042/bj1420065] [Citation(s) in RCA: 42] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
1. Trialkyltin, triphenyltin and diphenyleneiodonium compounds inhibited ADP-stimulated O(2) evolution by isolated pea chloroplasts in the presence of phosphate or arsenate. Tributyltin and triphenyltin were the most effective inhibitors, which suggests a highly hydrophobic site of action. Phenylmercuric acetate was a poor inhibitor of photophosphorylation, which suggests that thiol groups are not involved. 2. Triethyltin was a potent uncoupler of photophosphorylation by isolated chloroplasts in media containing Cl(-), but had little uncoupling activity when Cl(-) was replaced by NO(3) (-) or SO(4) (2-), which are inactive in the anion-hydroxide exchange. It is suggested that uncoupling by triethyltin is a result of the Cl(-)-OH(-) exchange together with a natural uniport of Cl(-). Tributyltin, triphenyltin and phenylmercuric acetate had low uncoupling activity, probably because in these compounds the uncoupling activity is partially masked by inhibitory effects. 3. At high concentrations the organotin compounds caused inhibition of electron transport uncoupled by carbonyl cyanide m-chlorophenylhydrazone or NH(4)Cl. At these high concentrations the organotin compounds may be producing a detergent-like disorganization of the membrane structure. In contrast, diphenyleneiodonium sulphate inhibited uncoupled electron transport at low concentrations; however, this inhibition is less than the inhibition of photophosphorylation, which suggests that the compound also inhibits the phosphorylation reactions as well as electron transport. 4. The effects of these compounds on basal electron transport were complex and depended on the pH of the reaction media. However, they can be explained on the basis of three actions: inhibition of the phosphorylation reactions, uncoupling and direct inhibition of electron transport. 5. The inhibition of cyclic photophosphorylation in the presence of phenazine methosulphate by diphenyleneiodonium sulphate shows that it inhibits in the region of photosystem 1.
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