RESUMEN
Dihydrolipoamide dehydrogenase (LADH) from Trypanosoma cruzi, the causative agent of Chagas' disease, was inactivated by treatment with myeloperoxidase (MPO)-dependent systems. LADH lipoamide reductase and diaphorase activities decreased as a function of incubation time and composition of the MPO/H2O2/halide system, a transient increase preceding the loss of diaphorase activity. Iodide, bromide, thiocyanide and chloride were effective components of MPO/H2O2 or MPO/NADH systems. Catalase prevented LADH inactivation by the MPO/NADH/halide systems in agreement with H2O2 production by NADH-supplemented LADH. Thiol compounds (L-cysteine, N-acetylcysteine, penicillamine, N-(2-mercaptopropionylglycine) and Captopril prevented LADH inactivation by the MPO/H2O2/NaCl system and by NaOCl, thus supporting HOCl as agent of the MPO/H2O2/NaCl system. MPO/H2O2/NaNO2 and MPO/NADH/NaNO2 inactivated LADH, the reaction being prevented by MPO inhibitors and thiol compounds. T. cruzi LADH was affected by MPO-dependent systems like myocardial LADH, allowance being made for the variation of the diaphorase activity and the greater sensitivity of the T. cruzi enzyme to MPO/H2O2/halide systems.
Asunto(s)
Dihidrolipoamida Deshidrogenasa/antagonistas & inhibidores , Ácido Hipocloroso/farmacología , Neutrófilos/fisiología , Nitritos/farmacología , Peroxidasa/fisiología , Proteínas Protozoarias/antagonistas & inhibidores , Estallido Respiratorio , Trypanosoma cruzi/enzimología , Acetilcisteína/farmacología , Animales , Bromuros/farmacología , Captopril/farmacología , Catalasa/farmacología , Cisteína/farmacología , Citotoxicidad Inmunológica , Glutatión/farmacología , Glicina/análogos & derivados , Glicina/farmacología , Humanos , Peróxido de Hidrógeno/farmacología , Cinética , Miocardio/enzimología , NAD/metabolismo , Neutrófilos/enzimología , Oxidación-Reducción , Penicilamina/farmacología , Especies Reactivas de Oxígeno/metabolismo , Proteínas Recombinantes/antagonistas & inhibidores , Cloruro de Sodio/farmacología , Compuestos de Sodio/farmacología , Compuestos de Sulfhidrilo/farmacología , Ácido Tióctico/análogos & derivados , Ácido Tióctico/metabolismo , Triptófano/farmacología , Tirosina/farmacologíaRESUMEN
Dihydrolipoamide dehydrogenase (LADH) from Trypanosoma cruzi, the causative agent of Chagas disease, was inactivated by treatment with myeloperoxidase (MPO)-dependent systems. LADH lipoamide reductase and diaphorase activities decreased as a function of incubation time and composition of the MPO/H2O2/halide system, a transient increase preceding the loss of diaphorase activity. Iodide, bromide, thiocyanide and chloride were effective components of MPO/H2O2 or MPO/NADH systems. Catalase prevented LADH inactivation by the MPO/NADH/halide systems in agreement with H2O2 production by NADH-supplemented LADH. Thiol compounds (L-cysteine, N-acetylcysteine, penicillamine, N-(2-mercaptopropionylglycine) and Captopril prevented LADH inactivation by the MPO/H2O2/NaCl system and by NaOCl, thus supporting HOCl as agent of the MPO/H2O2/NaCl system. MPO/H2O2/NaNO2 and MPO/NADH/NaNO2 inactivated LADH, the reaction being prevented by MPO inhibitors and thiol compounds. T. cruzi LADH was affected by MPO-dependent systems like myocardial LADH, allowance being made for the variation of the diaphorase activity and the greater sensitivity of the T. cruzi enzyme to MPO/H2O2/halide systems.(AU)
Asunto(s)
Animales , Humanos , RESEARCH SUPPORT, NON-U.S. GOVT , Ácido Hipocloroso/farmacología , Dihidrolipoamida Deshidrogenasa/antagonistas & inhibidores , Neutrófilos/fisiología , Nitritos/farmacología , Peroxidasa/fisiología , Proteínas Protozoarias/antagonistas & inhibidores , Estallido Respiratorio , Trypanosoma cruzi/enzimología , Acetilcisteína/farmacología , Bromuros/farmacología , Captopril/farmacología , Catalasa/farmacología , Cisteína/farmacología , Citotoxicidad Inmunológica , Glutatión/farmacología , Glicina/análogos & derivados , Glicina/farmacología , Peróxido de Hidrógeno/farmacología , Cinética , Miocardio/enzimología , NAD/metabolismo , Neutrófilos/enzimología , Oxidación-Reducción , Penicilamina/farmacología , Especies Reactivas de Oxígeno/metabolismo , Proteínas Recombinantes/antagonistas & inhibidores , Cloruro de Sodio/farmacología , Compuestos de Sodio/farmacología , Compuestos de Sulfhidrilo/farmacología , Ácido Tióctico/análogos & derivados , Ácido Tióctico/metabolismo , Triptófano/farmacología , Tirosina/farmacologíaRESUMEN
Dihydrolipoamide dehydrogenase (LADH) from Trypanosoma cruzi, the causative agent of Chagas' disease, was inactivated by treatment with myeloperoxidase (MPO)-dependent systems. LADH lipoamide reductase and diaphorase activities decreased as a function of incubation time and composition of the MPO/H2O2/halide system, a transient increase preceding the loss of diaphorase activity. Iodide, bromide, thiocyanide and chloride were effective components of MPO/H2O2 or MPO/NADH systems. Catalase prevented LADH inactivation by the MPO/NADH/halide systems in agreement with H2O2 production by NADH-supplemented LADH. Thiol compounds (L-cysteine, N-acetylcysteine, penicillamine, N-(2-mercaptopropionylglycine) and Captopril prevented LADH inactivation by the MPO/H2O2/NaCl system and by NaOCl, thus supporting HOCl as agent of the MPO/H2O2/NaCl system. MPO/H2O2/NaNO2 and MPO/NADH/NaNO2 inactivated LADH, the reaction being prevented by MPO inhibitors and thiol compounds. T. cruzi LADH was affected by MPO-dependent systems like myocardial LADH, allowance being made for the variation of the diaphorase activity and the greater sensitivity of the T. cruzi enzyme to MPO/H2O2/halide systems.
Asunto(s)
Animales , Humanos , Ácido Hipocloroso/farmacología , Dihidrolipoamida Deshidrogenasa , Neutrófilos/fisiología , Nitritos , Peroxidasa , Proteínas Protozoarias/antagonistas & inhibidores , Estallido Respiratorio , Trypanosoma cruzi , Acetilcisteína/farmacología , Ácido Tióctico/análogos & derivados , Ácido Tióctico/metabolismo , Bromuros , Captopril , Catalasa , Cisteína/farmacología , Cloruro de Sodio/farmacología , Compuestos de Sodio/farmacología , Citotoxicidad Inmunológica , Especies Reactivas de Oxígeno/metabolismo , Glutatión , Glicina , Cinética , Miocardio , NAD , Neutrófilos/enzimología , Oxidación-Reducción , Penicilamina , Peróxido de Hidrógeno/farmacología , Proteínas Recombinantes/antagonistas & inhibidores , Compuestos de Sulfhidrilo , Triptófano , TirosinaRESUMEN
Dihydrolipoamide dehydrogenase (LADH) from Trypanosoma cruzi was inactivated by treatment with myeloperoxidase (MPO)-dependent systems. With MPO/H2O2/NaCl, LADH lipoamide reductase and diaphorase activities significantly decreased as a function of incubation time. Iodide, bromide, thiocyanide and chloride effectively supplemented the MPO/H2O2 system, KI and NaCl being the most and the least effective supplements, respectively. LADH inactivation by MPO/H2O2/NaCl and by NaOCl was similarly prevented by thiol compounds such as GSH, L-cysteine, N-acetylcysteine, penicillamine and N-(2-mercaptopropionyl-glycine) in agreement with the role of HOCI in LADH inactivation by MPO/H2O2/NaCl. LADH was also inactivated by MPO/NADH/halide, MPO/H2O2/NaNO2 and MPO/NADH/NaNO2 systems. Catalase prevented the action of the NADH-dependent systems, thus supporting H2O2 production by NADH-supplemented LADH. MPO inhibitors (4-aminobenzoic acid hydrazide, and isoniazid), GSH, L-cysteine, L-methionine and L-tryptophan prevented LADH inactivation by MPO/H2O2/NaNO2. Other MPO systems inactivating LADH were (a) MPO/H2O2/chlorpromazine; (b) MPO/H2O2/monophenolic systems, including L-tyrosine, serotonin and acetaminophen and (c) MPO/H2O2/di- and polyphenolic systems, including norepinephrine, catechol, nordihydroguaiaretic acid, caffeic acid, quercetin and catechin. Comparison of the above effects and those previously reported with pig myocardial LADH indicates that both enzymes were similarly affected by the MPO-dependent systems, allowance being made for T. cruzi LADH diaphorase inactivation and the greater sensitivity of its LADH lipoamide reductase activity towards the MPO/H2O2/NaCl system and NaOCl.
Asunto(s)
Dihidrolipoamida Deshidrogenasa/antagonistas & inhibidores , Peroxidasa/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Trypanosoma cruzi/enzimología , Animales , Inhibidores Enzimáticos/farmacología , Peróxido de Hidrógeno/metabolismo , Peróxido de Hidrógeno/farmacología , Técnicas In Vitro , Peroxidasa/farmacología , Fenol/metabolismo , Fenol/farmacología , Fenotiazinas/metabolismo , Fenotiazinas/farmacología , Sales (Química)/metabolismo , Sales (Química)/farmacología , Nitrito de Sodio/metabolismo , Nitrito de Sodio/farmacologíaRESUMEN
Dihydrolipoamide dehydrogenase (LADH) from Trypanosoma cruzi, the causative agent of Chagas disease, was inactivated by treatment with myeloperoxidase (MPO)-dependent systems. LADH lipoamide reductase and diaphorase activities decreased as a function of incubation time and composition of the MPO/H2O2/halide system, a transient increase preceding the loss of diaphorase activity. Iodide, bromide, thiocyanide and chloride were effective components of MPO/H2O2 or MPO/NADH systems. Catalase prevented LADH inactivation by the MPO/NADH/halide systems in agreement with H2O2 production by NADH-supplemented LADH. Thiol compounds (L-cysteine, N-acetylcysteine, penicillamine, N-(2-mercaptopropionylglycine) and Captopril prevented LADH inactivation by the MPO/H2O2/NaCl system and by NaOCl, thus supporting HOCl as agent of the MPO/H2O2/NaCl system. MPO/H2O2/NaNO2 and MPO/NADH/NaNO2 inactivated LADH, the reaction being prevented by MPO inhibitors and thiol compounds. T. cruzi LADH was affected by MPO-dependent systems like myocardial LADH, allowance being made for the variation of the diaphorase activity and the greater sensitivity of the T. cruzi enzyme to MPO/H2O2/halide systems.