The Experts below are selected from a list of 183 Experts worldwide ranked by ideXlab platform
Paolo Bernardi - One of the best experts on this subject based on the ideXlab platform.
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modification of permeability transition pore arginine s by Phenylglyoxal derivatives in isolated mitochondria and mammalian cells structure function relationship of arginine ligands
Journal of Biological Chemistry, 2005Co-Authors: Milena Johans, Eva Milanesi, Marina Franck, Christoffer Johans, Julius Liobikas, Maria Panagiotaki, Lucedio Greci, Giovanni Principato, Paavo K J Kinnunen, Paolo BernardiAbstract:Methylglyoxal and synthetic glyoxal derivatives react covalently with arginine residue(s) on the mitochondrial permeability transition pore (PTP). In this study, we have investigated how the binding of a panel of synthetic Phenylglyoxal derivatives influences the opening and closing of the PTP. Using both isolated mitochondria and mammalian cells, we demonstrate that the resulting arginine-Phenylglyoxal adduct can lead to either suppression or induction of permeability transition, depending on the net charge and hydrogen bonding capacity of the adduct. We report that Phenylglyoxal derivatives that possess a net negative charge and/or are capable of forming hydrogen bonds induced permeability transition. Derivatives that were overall electroneutral and cannot form hydrogen bonds suppressed permeability transition. When mammalian cells were incubated with low concentrations of negatively charged Phenylglyoxal derivatives, the addition of oligomycin caused a depolarization of the mitochondrial membrane potential. This depolarization was completely blocked by cyclosporin A, a PTP opening inhibitor, indicating that the depolarization was due to PTP opening. Collectively, these findings highlight that the target arginine(s) is functionally linked with the opening/closing mechanism of the PTP and that the electric charge and hydrogen bonding of the resulting arginine adduct influences the conformation of the PTP. These results are consistent with a model where the target arginine plays a role as a voltage sensor.
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chemical modification of arginines by 2 3 butanedione and Phenylglyoxal causes closure of the mitochondrial permeability transition pore
Journal of Biological Chemistry, 1998Co-Authors: Ove Eriksson, Eric Fontaine, Paolo BernardiAbstract:Abstract We have investigated the role of arginine residues in the regulation of the mitochondrial permeability transition pore, a cyclosporin A-sensitive inner membrane channel. Isolated rat liver mitochondria were treated with the arginine-specific chemical reagent 2,3-butanedione or Phenylglyoxal, followed by removal of excess free reagent. After this treatment, mitochondria accumulated Ca2+ normally, but did not undergo permeability transition following depolarization, a condition that normally triggers opening of the permeability transition pore. Inhibition by 2,3-butanedione and Phenylglyoxal correlated with matrix pH, suggesting that the relevant arginine(s) are exposed to the matrix aqueous phase. Inhibition by 2,3-butanedione was potentiated by borate and was reversed upon its removal, whereas inhibition by Phenylglyoxal was irreversible. Treatment with 2,3-butanedione or Phenylglyoxal after induction of the permeability transition by Ca2+ overload resulted in pore closure despite the presence of 0.5 mmCa2+. At concentrations that were fully effective at inhibiting the permeability transition, these arginine reagents (i) had no effect on the isomerase activity of cyclophilin D and (ii) did not affect the rate of ATP translocation and hydrolysis, as measured by the production of a membrane potential upon ATP addition in the presence of rotenone. We conclude that reaction with 2,3-butanedione and Phenylglyoxal results in a stable chemical modification of critical arginine residue(s) located on the matrix side of the inner membrane, which, in turn, strongly favors a closed state of the pore.
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inhibition of the mitochondrial cyclosporin a sensitive permeability transition pore by the arginine reagent Phenylglyoxal
FEBS Letters, 1997Co-Authors: Ove Eriksson, Eric Fontaine, Valeria Petronilli, Paolo BernardiAbstract:Abstract The mitochondrial permeability transition pore, a cyclosporin A-sensitive channel, is controlled by the transmembrane electric potential difference across the inner membrane. Here, we show that treatment of rat liver mitochondria with the arginine reagent Phenylglyoxal inhibits the permeability transition pore triggered by depolarization with uncoupler after Ca2+ accumulation. Phenylglyoxal does not change the extent of mitochondrial Ca2+ uptake or the extent of membrane depolarization, indicating that covalent modification of arginine (and possibly lysine) residues directly affects the open probability of the pore. We propose that arginine residues play a role in the physiological control of the permeability transition pore by the mitochondrial transmembrane potential.
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Inhibition of the mitochondrial cyclosporin A‐sensitive permeability transition pore by the arginine reagent Phenylglyoxal
FEBS Letters, 1997Co-Authors: Ove Eriksson, Eric Fontaine, Valeria Petronilli, Paolo BernardiAbstract:Abstract The mitochondrial permeability transition pore, a cyclosporin A-sensitive channel, is controlled by the transmembrane electric potential difference across the inner membrane. Here, we show that treatment of rat liver mitochondria with the arginine reagent Phenylglyoxal inhibits the permeability transition pore triggered by depolarization with uncoupler after Ca2+ accumulation. Phenylglyoxal does not change the extent of mitochondrial Ca2+ uptake or the extent of membrane depolarization, indicating that covalent modification of arginine (and possibly lysine) residues directly affects the open probability of the pore. We propose that arginine residues play a role in the physiological control of the permeability transition pore by the mitochondrial transmembrane potential.
Ove Eriksson - One of the best experts on this subject based on the ideXlab platform.
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chemical modification of arginines by 2 3 butanedione and Phenylglyoxal causes closure of the mitochondrial permeability transition pore
Journal of Biological Chemistry, 1998Co-Authors: Ove Eriksson, Eric Fontaine, Paolo BernardiAbstract:Abstract We have investigated the role of arginine residues in the regulation of the mitochondrial permeability transition pore, a cyclosporin A-sensitive inner membrane channel. Isolated rat liver mitochondria were treated with the arginine-specific chemical reagent 2,3-butanedione or Phenylglyoxal, followed by removal of excess free reagent. After this treatment, mitochondria accumulated Ca2+ normally, but did not undergo permeability transition following depolarization, a condition that normally triggers opening of the permeability transition pore. Inhibition by 2,3-butanedione and Phenylglyoxal correlated with matrix pH, suggesting that the relevant arginine(s) are exposed to the matrix aqueous phase. Inhibition by 2,3-butanedione was potentiated by borate and was reversed upon its removal, whereas inhibition by Phenylglyoxal was irreversible. Treatment with 2,3-butanedione or Phenylglyoxal after induction of the permeability transition by Ca2+ overload resulted in pore closure despite the presence of 0.5 mmCa2+. At concentrations that were fully effective at inhibiting the permeability transition, these arginine reagents (i) had no effect on the isomerase activity of cyclophilin D and (ii) did not affect the rate of ATP translocation and hydrolysis, as measured by the production of a membrane potential upon ATP addition in the presence of rotenone. We conclude that reaction with 2,3-butanedione and Phenylglyoxal results in a stable chemical modification of critical arginine residue(s) located on the matrix side of the inner membrane, which, in turn, strongly favors a closed state of the pore.
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inhibition of the mitochondrial cyclosporin a sensitive permeability transition pore by the arginine reagent Phenylglyoxal
FEBS Letters, 1997Co-Authors: Ove Eriksson, Eric Fontaine, Valeria Petronilli, Paolo BernardiAbstract:Abstract The mitochondrial permeability transition pore, a cyclosporin A-sensitive channel, is controlled by the transmembrane electric potential difference across the inner membrane. Here, we show that treatment of rat liver mitochondria with the arginine reagent Phenylglyoxal inhibits the permeability transition pore triggered by depolarization with uncoupler after Ca2+ accumulation. Phenylglyoxal does not change the extent of mitochondrial Ca2+ uptake or the extent of membrane depolarization, indicating that covalent modification of arginine (and possibly lysine) residues directly affects the open probability of the pore. We propose that arginine residues play a role in the physiological control of the permeability transition pore by the mitochondrial transmembrane potential.
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Inhibition of the mitochondrial cyclosporin A‐sensitive permeability transition pore by the arginine reagent Phenylglyoxal
FEBS Letters, 1997Co-Authors: Ove Eriksson, Eric Fontaine, Valeria Petronilli, Paolo BernardiAbstract:Abstract The mitochondrial permeability transition pore, a cyclosporin A-sensitive channel, is controlled by the transmembrane electric potential difference across the inner membrane. Here, we show that treatment of rat liver mitochondria with the arginine reagent Phenylglyoxal inhibits the permeability transition pore triggered by depolarization with uncoupler after Ca2+ accumulation. Phenylglyoxal does not change the extent of mitochondrial Ca2+ uptake or the extent of membrane depolarization, indicating that covalent modification of arginine (and possibly lysine) residues directly affects the open probability of the pore. We propose that arginine residues play a role in the physiological control of the permeability transition pore by the mitochondrial transmembrane potential.
Eric Fontaine - One of the best experts on this subject based on the ideXlab platform.
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chemical modification of arginines by 2 3 butanedione and Phenylglyoxal causes closure of the mitochondrial permeability transition pore
Journal of Biological Chemistry, 1998Co-Authors: Ove Eriksson, Eric Fontaine, Paolo BernardiAbstract:Abstract We have investigated the role of arginine residues in the regulation of the mitochondrial permeability transition pore, a cyclosporin A-sensitive inner membrane channel. Isolated rat liver mitochondria were treated with the arginine-specific chemical reagent 2,3-butanedione or Phenylglyoxal, followed by removal of excess free reagent. After this treatment, mitochondria accumulated Ca2+ normally, but did not undergo permeability transition following depolarization, a condition that normally triggers opening of the permeability transition pore. Inhibition by 2,3-butanedione and Phenylglyoxal correlated with matrix pH, suggesting that the relevant arginine(s) are exposed to the matrix aqueous phase. Inhibition by 2,3-butanedione was potentiated by borate and was reversed upon its removal, whereas inhibition by Phenylglyoxal was irreversible. Treatment with 2,3-butanedione or Phenylglyoxal after induction of the permeability transition by Ca2+ overload resulted in pore closure despite the presence of 0.5 mmCa2+. At concentrations that were fully effective at inhibiting the permeability transition, these arginine reagents (i) had no effect on the isomerase activity of cyclophilin D and (ii) did not affect the rate of ATP translocation and hydrolysis, as measured by the production of a membrane potential upon ATP addition in the presence of rotenone. We conclude that reaction with 2,3-butanedione and Phenylglyoxal results in a stable chemical modification of critical arginine residue(s) located on the matrix side of the inner membrane, which, in turn, strongly favors a closed state of the pore.
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inhibition of the mitochondrial cyclosporin a sensitive permeability transition pore by the arginine reagent Phenylglyoxal
FEBS Letters, 1997Co-Authors: Ove Eriksson, Eric Fontaine, Valeria Petronilli, Paolo BernardiAbstract:Abstract The mitochondrial permeability transition pore, a cyclosporin A-sensitive channel, is controlled by the transmembrane electric potential difference across the inner membrane. Here, we show that treatment of rat liver mitochondria with the arginine reagent Phenylglyoxal inhibits the permeability transition pore triggered by depolarization with uncoupler after Ca2+ accumulation. Phenylglyoxal does not change the extent of mitochondrial Ca2+ uptake or the extent of membrane depolarization, indicating that covalent modification of arginine (and possibly lysine) residues directly affects the open probability of the pore. We propose that arginine residues play a role in the physiological control of the permeability transition pore by the mitochondrial transmembrane potential.
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Inhibition of the mitochondrial cyclosporin A‐sensitive permeability transition pore by the arginine reagent Phenylglyoxal
FEBS Letters, 1997Co-Authors: Ove Eriksson, Eric Fontaine, Valeria Petronilli, Paolo BernardiAbstract:Abstract The mitochondrial permeability transition pore, a cyclosporin A-sensitive channel, is controlled by the transmembrane electric potential difference across the inner membrane. Here, we show that treatment of rat liver mitochondria with the arginine reagent Phenylglyoxal inhibits the permeability transition pore triggered by depolarization with uncoupler after Ca2+ accumulation. Phenylglyoxal does not change the extent of mitochondrial Ca2+ uptake or the extent of membrane depolarization, indicating that covalent modification of arginine (and possibly lysine) residues directly affects the open probability of the pore. We propose that arginine residues play a role in the physiological control of the permeability transition pore by the mitochondrial transmembrane potential.
Valeria Petronilli - One of the best experts on this subject based on the ideXlab platform.
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inhibition of the mitochondrial cyclosporin a sensitive permeability transition pore by the arginine reagent Phenylglyoxal
FEBS Letters, 1997Co-Authors: Ove Eriksson, Eric Fontaine, Valeria Petronilli, Paolo BernardiAbstract:Abstract The mitochondrial permeability transition pore, a cyclosporin A-sensitive channel, is controlled by the transmembrane electric potential difference across the inner membrane. Here, we show that treatment of rat liver mitochondria with the arginine reagent Phenylglyoxal inhibits the permeability transition pore triggered by depolarization with uncoupler after Ca2+ accumulation. Phenylglyoxal does not change the extent of mitochondrial Ca2+ uptake or the extent of membrane depolarization, indicating that covalent modification of arginine (and possibly lysine) residues directly affects the open probability of the pore. We propose that arginine residues play a role in the physiological control of the permeability transition pore by the mitochondrial transmembrane potential.
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Inhibition of the mitochondrial cyclosporin A‐sensitive permeability transition pore by the arginine reagent Phenylglyoxal
FEBS Letters, 1997Co-Authors: Ove Eriksson, Eric Fontaine, Valeria Petronilli, Paolo BernardiAbstract:Abstract The mitochondrial permeability transition pore, a cyclosporin A-sensitive channel, is controlled by the transmembrane electric potential difference across the inner membrane. Here, we show that treatment of rat liver mitochondria with the arginine reagent Phenylglyoxal inhibits the permeability transition pore triggered by depolarization with uncoupler after Ca2+ accumulation. Phenylglyoxal does not change the extent of mitochondrial Ca2+ uptake or the extent of membrane depolarization, indicating that covalent modification of arginine (and possibly lysine) residues directly affects the open probability of the pore. We propose that arginine residues play a role in the physiological control of the permeability transition pore by the mitochondrial transmembrane potential.
Mohammad K Amini - One of the best experts on this subject based on the ideXlab platform.
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coated wire copper ii selective electrode based on Phenylglyoxal α monoxime ionophore
Analytical and Bioanalytical Chemistry, 2002Co-Authors: Ali R Firooz, M Mazloum, Javad Safari, Mohammad K AminiAbstract:A copper(II) ion-selective electrode based on a recently synthesized 2-quinolyl-2-Phenylglyoxal-2-oxime (Phenylglyoxal-α-monoxime) has been developed. The PVC-based membrane containing Phenylglyoxal-α-monoxime, dibutyl phthalate as plasticizer, and sodium tetraphenylborate as anion excluder and membrane modifier, was directly coated on the surface of a platinum-wire electrode. The response of the electrode was linear with a near-Nernstian slope of 28.2 mV decade–1 within the Cu2+ ion concentration range 1×10–6–1×10–1 mol L–1. The response time for the proposed electrode to achieve a 95% steady potential for Cu2+ concentrations ranging from 1×10–1 to 1×10–6 mol L–1 is between 10 and 50 s, and the electrode is suitable for use within the pH range of 3 to 6.5. The electrode has a detection limit of 5×10–7 mol L–1 Cu2+ and its selectivity relative to several alkali, alkaline earth, transition, and heavy metal ions was good. The coated-wire electrode could be used for at least two months without a considerable alteration of its potential. Applications of the electrode for determination of copper in milk powder samples and as an indicator electrode for potentiometric titration of Cu2+ ion using EDTA are reported.
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Coated-wire copper(II)-selective electrode based on Phenylglyoxal-alpha-monoxime ionophore.
Analytical and bioanalytical chemistry, 2002Co-Authors: Ali R Firooz, M Mazloum, Javad Safari, Mohammad K AminiAbstract:A copper(II) ion-selective electrode based on a recently synthesized 2-quinolyl-2-Phenylglyoxal-2-oxime (Phenylglyoxal-alpha-monoxime) has been developed. The PVC-based membrane containing Phenylglyoxal-alpha-monoxime, dibutyl phthalate as plasticizer, and sodium tetraphenylborate as anion excluder and membrane modifier, was directly coated on the surface of a platinum-wire electrode. The response of the electrode was linear with a near-Nernstian slope of 28.2 mV decade(-1) within the Cu2+ ion concentration range 1x10(-6)-1x10(-1) mol x L(-1). The response time for the proposed electrode to achieve a 95% steady potential for Cu2+ concentrations ranging from 1x10(-1) to 1x10(-6) mol x L(-1) is between 10 and 50 s, and the electrode is suitable for use within the pH range of 3 to 6.5. The electrode has a detection limit of 5x10(-7) mol x L(-1) Cu2+ and its selectivity relative to several alkali, alkaline earth, transition, and heavy metal ions was good. The coated-wire electrode could be used for at least two months without a considerable alteration of its potential. Applications of the electrode for determination of copper in milk powder samples and as an indicator electrode for potentiometric titration of Cu2+ ion using EDTA are reported.
