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Sonia R W Louro - One of the best experts on this subject based on the ideXlab platform.

  • methyl parathion interaction with human and Bovine Serum Albumin
    Toxicology Letters, 2004
    Co-Authors: Dilson Silva, Celia Martins Cortez, Jayme Cunhabastos, Sonia R W Louro
    Abstract:

    Abstract Methyl parathion (MP; O , O -dimethyl O - p -nitrophenyl phosphorothioate) is an organophosphorous compound still largely used in agriculture and fish hatcheries. This pesticide is not quite selective and is potentially toxic for both vertebrates and invertebrates. Its mechanism of acute toxicity is the inhibition of the enzyme acetylcholinesterase in nervous tissue. Binding of pesticides to plasma proteins is one of many factors that influence their distribution and elimination. The free concentration available for toxic action can be effectively reduced for pesticides with high binding to plasma proteins, although the affinity of pesticides to plasma proteins is often lower than for the enzyme targets. Several different transport proteins exist in blood plasma, but Albumin only is able to bind a wide diversity of xenobiotics reversibly with high affinity. It was already known that parathion (ethyl parathion) exhibits a high affinity to human and Bovine Serum Albumins. We studied interactions of methyl parathion with these Albumins by using fluorescence quenching techniques. We selectively excited the fluorescence of tryptophan residues with a 290 nm wavelength light, and observed quenching by titrating human and Bovine Serum Albumin solutions with methyl parathion. Stern–Volmer graphs were plotted and quenching constants were estimated. Our results pointed to the formation of complexes of methyl parathion with Albumins. Association constants at 25 °C were 3.07×10 4 (1.2×10 3 ) M −1 for human Serum Albumin, and 1.96×10 4 (±4.5×10 2 ) M −1 for Bovine Serum Albumin. At 37 °C, they were 1.08×10 4 (±2.0×10 2 ) M −1 for human Serum Albumin, and 8.16×10 3 (±1.9×10 2 ) M −1 for Bovine Serum Albumin. Results also suggest that the primary binding site for methyl parathion on Albumin is close to tryptophan residues 214 of human Serum Albumin and 212 of Bovine Serum Albumin.

  • Methyl parathion interaction with human and Bovine Serum Albumin
    Toxicology Letters, 2004
    Co-Authors: Dilson Silva, Celia Martins Cortez, Jayme Cunha-bastos, Sonia R W Louro
    Abstract:

    Methyl parathion (MP; O,O-dimethyl O-p-nitrophenyl phosphorothioate) is an organophosphorous compound still largely used in agriculture and fish hatcheries. This pesticide is not quite selective and is potentially toxic for both vertebrates and invertebrates. Its mechanism of acute toxicity is the inhibition of the enzyme acetylcholinesterase in nervous tissue. Binding of pesticides to plasma proteins is one of many factors that influence their distribution and elimination. The free concentration available for toxic action can be effectively reduced for pesticides with high binding to plasma proteins, although the affinity of pesticides to plasma proteins is often lower than for the enzyme targets. Several different transport proteins exist in blood plasma, but Albumin only is able to bind a wide diversity of xenobiotics reversibly with high affinity. It was already known that parathion (ethyl parathion) exhibits a high affinity to human and Bovine Serum Albumins. We studied interactions of methyl parathion with these Albumins by using fluorescence quenching techniques. We selectively excited the fluorescence of tryptophan residues with a 290 nm wavelength light, and observed quenching by titrating human and Bovine Serum Albumin solutions with methyl parathion. Stern-Volmer graphs were plotted and quenching constants were estimated. Our results pointed to the formation of complexes of methyl parathion with Albumins. Association constants at 25 degrees C were 3.07 x 10(4) (1.2 x 10(3))M(-1) for human Serum Albumin, and 1.96 x 10(4) (+/- 4.5 x 10(2))M(-1) for Bovine Serum Albumin. At 37 degrees C, they were 1.08 x 10(4) (+/- 2.0 x 10(2))M(-1) for human Serum Albumin, and 8.16 x 10(3) (+/- 1.9 x 10(2))M(-1) for Bovine Serum Albumin. Results also suggest that the primary binding site for methyl parathion on Albumin is close to tryptophan residues 214 of human Serum Albumin and 212 of Bovine Serum Albumin.

Dilson Silva - One of the best experts on this subject based on the ideXlab platform.

  • methyl parathion interaction with human and Bovine Serum Albumin
    Toxicology Letters, 2004
    Co-Authors: Dilson Silva, Celia Martins Cortez, Jayme Cunhabastos, Sonia R W Louro
    Abstract:

    Abstract Methyl parathion (MP; O , O -dimethyl O - p -nitrophenyl phosphorothioate) is an organophosphorous compound still largely used in agriculture and fish hatcheries. This pesticide is not quite selective and is potentially toxic for both vertebrates and invertebrates. Its mechanism of acute toxicity is the inhibition of the enzyme acetylcholinesterase in nervous tissue. Binding of pesticides to plasma proteins is one of many factors that influence their distribution and elimination. The free concentration available for toxic action can be effectively reduced for pesticides with high binding to plasma proteins, although the affinity of pesticides to plasma proteins is often lower than for the enzyme targets. Several different transport proteins exist in blood plasma, but Albumin only is able to bind a wide diversity of xenobiotics reversibly with high affinity. It was already known that parathion (ethyl parathion) exhibits a high affinity to human and Bovine Serum Albumins. We studied interactions of methyl parathion with these Albumins by using fluorescence quenching techniques. We selectively excited the fluorescence of tryptophan residues with a 290 nm wavelength light, and observed quenching by titrating human and Bovine Serum Albumin solutions with methyl parathion. Stern–Volmer graphs were plotted and quenching constants were estimated. Our results pointed to the formation of complexes of methyl parathion with Albumins. Association constants at 25 °C were 3.07×10 4 (1.2×10 3 ) M −1 for human Serum Albumin, and 1.96×10 4 (±4.5×10 2 ) M −1 for Bovine Serum Albumin. At 37 °C, they were 1.08×10 4 (±2.0×10 2 ) M −1 for human Serum Albumin, and 8.16×10 3 (±1.9×10 2 ) M −1 for Bovine Serum Albumin. Results also suggest that the primary binding site for methyl parathion on Albumin is close to tryptophan residues 214 of human Serum Albumin and 212 of Bovine Serum Albumin.

  • Methyl parathion interaction with human and Bovine Serum Albumin
    Toxicology Letters, 2004
    Co-Authors: Dilson Silva, Celia Martins Cortez, Jayme Cunha-bastos, Sonia R W Louro
    Abstract:

    Methyl parathion (MP; O,O-dimethyl O-p-nitrophenyl phosphorothioate) is an organophosphorous compound still largely used in agriculture and fish hatcheries. This pesticide is not quite selective and is potentially toxic for both vertebrates and invertebrates. Its mechanism of acute toxicity is the inhibition of the enzyme acetylcholinesterase in nervous tissue. Binding of pesticides to plasma proteins is one of many factors that influence their distribution and elimination. The free concentration available for toxic action can be effectively reduced for pesticides with high binding to plasma proteins, although the affinity of pesticides to plasma proteins is often lower than for the enzyme targets. Several different transport proteins exist in blood plasma, but Albumin only is able to bind a wide diversity of xenobiotics reversibly with high affinity. It was already known that parathion (ethyl parathion) exhibits a high affinity to human and Bovine Serum Albumins. We studied interactions of methyl parathion with these Albumins by using fluorescence quenching techniques. We selectively excited the fluorescence of tryptophan residues with a 290 nm wavelength light, and observed quenching by titrating human and Bovine Serum Albumin solutions with methyl parathion. Stern-Volmer graphs were plotted and quenching constants were estimated. Our results pointed to the formation of complexes of methyl parathion with Albumins. Association constants at 25 degrees C were 3.07 x 10(4) (1.2 x 10(3))M(-1) for human Serum Albumin, and 1.96 x 10(4) (+/- 4.5 x 10(2))M(-1) for Bovine Serum Albumin. At 37 degrees C, they were 1.08 x 10(4) (+/- 2.0 x 10(2))M(-1) for human Serum Albumin, and 8.16 x 10(3) (+/- 1.9 x 10(2))M(-1) for Bovine Serum Albumin. Results also suggest that the primary binding site for methyl parathion on Albumin is close to tryptophan residues 214 of human Serum Albumin and 212 of Bovine Serum Albumin.

Celia Martins Cortez - One of the best experts on this subject based on the ideXlab platform.

  • methyl parathion interaction with human and Bovine Serum Albumin
    Toxicology Letters, 2004
    Co-Authors: Dilson Silva, Celia Martins Cortez, Jayme Cunhabastos, Sonia R W Louro
    Abstract:

    Abstract Methyl parathion (MP; O , O -dimethyl O - p -nitrophenyl phosphorothioate) is an organophosphorous compound still largely used in agriculture and fish hatcheries. This pesticide is not quite selective and is potentially toxic for both vertebrates and invertebrates. Its mechanism of acute toxicity is the inhibition of the enzyme acetylcholinesterase in nervous tissue. Binding of pesticides to plasma proteins is one of many factors that influence their distribution and elimination. The free concentration available for toxic action can be effectively reduced for pesticides with high binding to plasma proteins, although the affinity of pesticides to plasma proteins is often lower than for the enzyme targets. Several different transport proteins exist in blood plasma, but Albumin only is able to bind a wide diversity of xenobiotics reversibly with high affinity. It was already known that parathion (ethyl parathion) exhibits a high affinity to human and Bovine Serum Albumins. We studied interactions of methyl parathion with these Albumins by using fluorescence quenching techniques. We selectively excited the fluorescence of tryptophan residues with a 290 nm wavelength light, and observed quenching by titrating human and Bovine Serum Albumin solutions with methyl parathion. Stern–Volmer graphs were plotted and quenching constants were estimated. Our results pointed to the formation of complexes of methyl parathion with Albumins. Association constants at 25 °C were 3.07×10 4 (1.2×10 3 ) M −1 for human Serum Albumin, and 1.96×10 4 (±4.5×10 2 ) M −1 for Bovine Serum Albumin. At 37 °C, they were 1.08×10 4 (±2.0×10 2 ) M −1 for human Serum Albumin, and 8.16×10 3 (±1.9×10 2 ) M −1 for Bovine Serum Albumin. Results also suggest that the primary binding site for methyl parathion on Albumin is close to tryptophan residues 214 of human Serum Albumin and 212 of Bovine Serum Albumin.

  • Methyl parathion interaction with human and Bovine Serum Albumin
    Toxicology Letters, 2004
    Co-Authors: Dilson Silva, Celia Martins Cortez, Jayme Cunha-bastos, Sonia R W Louro
    Abstract:

    Methyl parathion (MP; O,O-dimethyl O-p-nitrophenyl phosphorothioate) is an organophosphorous compound still largely used in agriculture and fish hatcheries. This pesticide is not quite selective and is potentially toxic for both vertebrates and invertebrates. Its mechanism of acute toxicity is the inhibition of the enzyme acetylcholinesterase in nervous tissue. Binding of pesticides to plasma proteins is one of many factors that influence their distribution and elimination. The free concentration available for toxic action can be effectively reduced for pesticides with high binding to plasma proteins, although the affinity of pesticides to plasma proteins is often lower than for the enzyme targets. Several different transport proteins exist in blood plasma, but Albumin only is able to bind a wide diversity of xenobiotics reversibly with high affinity. It was already known that parathion (ethyl parathion) exhibits a high affinity to human and Bovine Serum Albumins. We studied interactions of methyl parathion with these Albumins by using fluorescence quenching techniques. We selectively excited the fluorescence of tryptophan residues with a 290 nm wavelength light, and observed quenching by titrating human and Bovine Serum Albumin solutions with methyl parathion. Stern-Volmer graphs were plotted and quenching constants were estimated. Our results pointed to the formation of complexes of methyl parathion with Albumins. Association constants at 25 degrees C were 3.07 x 10(4) (1.2 x 10(3))M(-1) for human Serum Albumin, and 1.96 x 10(4) (+/- 4.5 x 10(2))M(-1) for Bovine Serum Albumin. At 37 degrees C, they were 1.08 x 10(4) (+/- 2.0 x 10(2))M(-1) for human Serum Albumin, and 8.16 x 10(3) (+/- 1.9 x 10(2))M(-1) for Bovine Serum Albumin. Results also suggest that the primary binding site for methyl parathion on Albumin is close to tryptophan residues 214 of human Serum Albumin and 212 of Bovine Serum Albumin.

Jayme Cunhabastos - One of the best experts on this subject based on the ideXlab platform.

  • methyl parathion interaction with human and Bovine Serum Albumin
    Toxicology Letters, 2004
    Co-Authors: Dilson Silva, Celia Martins Cortez, Jayme Cunhabastos, Sonia R W Louro
    Abstract:

    Abstract Methyl parathion (MP; O , O -dimethyl O - p -nitrophenyl phosphorothioate) is an organophosphorous compound still largely used in agriculture and fish hatcheries. This pesticide is not quite selective and is potentially toxic for both vertebrates and invertebrates. Its mechanism of acute toxicity is the inhibition of the enzyme acetylcholinesterase in nervous tissue. Binding of pesticides to plasma proteins is one of many factors that influence their distribution and elimination. The free concentration available for toxic action can be effectively reduced for pesticides with high binding to plasma proteins, although the affinity of pesticides to plasma proteins is often lower than for the enzyme targets. Several different transport proteins exist in blood plasma, but Albumin only is able to bind a wide diversity of xenobiotics reversibly with high affinity. It was already known that parathion (ethyl parathion) exhibits a high affinity to human and Bovine Serum Albumins. We studied interactions of methyl parathion with these Albumins by using fluorescence quenching techniques. We selectively excited the fluorescence of tryptophan residues with a 290 nm wavelength light, and observed quenching by titrating human and Bovine Serum Albumin solutions with methyl parathion. Stern–Volmer graphs were plotted and quenching constants were estimated. Our results pointed to the formation of complexes of methyl parathion with Albumins. Association constants at 25 °C were 3.07×10 4 (1.2×10 3 ) M −1 for human Serum Albumin, and 1.96×10 4 (±4.5×10 2 ) M −1 for Bovine Serum Albumin. At 37 °C, they were 1.08×10 4 (±2.0×10 2 ) M −1 for human Serum Albumin, and 8.16×10 3 (±1.9×10 2 ) M −1 for Bovine Serum Albumin. Results also suggest that the primary binding site for methyl parathion on Albumin is close to tryptophan residues 214 of human Serum Albumin and 212 of Bovine Serum Albumin.

Kuntebommanahally Nagojappa Thimmaiah - One of the best experts on this subject based on the ideXlab platform.

  • interaction of substituted phenoxazine chemosensitizers with Bovine Serum Albumin
    Journal of Pharmaceutical and Biomedical Analysis, 1999
    Co-Authors: B C Channu, H N Kalpana, Gangasamudra B Eregowda, Chhabil Dass, Peter J Houghton, Kuntebommanahally Nagojappa Thimmaiah
    Abstract:

    The binding of 10-3'-N-bis(hydroxyethyl)amino]propyl]phenoxazine BPP], 10-3'-N-bis(hydroxyethyl)amino]propyl]-2-chlorophenoxazine BPCP], 10-3'-N-bis-(hydroxyethyl)amino]propyl]-2-trifluoromethylphenoxazi ne BPFP], 10-(3'-N-pyrrolidino propyl)-2-chlorophenoxazine PPCP] or 10-(3'-N-pyrrolidinopropyl)-2-trifluoromethylphenoxazine PPFP] to Bovine Serum Albumin (BSA) has been measured by gel filtration and equilibrium dialysis methods. The binding of these modulators to Bovine Serum Albumin based on dialysis experiments has been characterized by the following parameters: percentage (beta) of bound drug, the association constant `K-1', the apparent binding constant `k' and the free energy Delta F degrees. The binding of phenoxazine derivatives to Bovine Serum Albumin is correlated with their octanol-water partition coefficient, log(10) P. In addition, the displacing activity of hydroxyzine and acetylsalicylic acid on the binding of phenoxazines to Albumin has been studied. The results of the displacing experiments showed that the phenoxazine benzene rings and the tertiary amines attached to the side chain of the phenoxazine moiety are bound to a hydrophobic area on the Albumin molecule. (C) 1999 Elsevier Science B.V. All rights reserved.