Inactivation of Trypanosoma cruzi dihydrolipoamide dehydrogenase by leukocyte myeloperoxidase systems: role of hypochloride and nitrite related radicals
Rev. argent. microbiol
;
32(3): 136-143, jul.-sept. 2000.
Article
in English
| LILACS
| ID: lil-332524
RESUMO
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.
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Index:
LILACS (Americas)
Main subject:
Trypanosoma cruzi
/
Protozoan Proteins
/
Respiratory Burst
/
Hypochlorous Acid
/
Peroxidase
/
Dihydrolipoamide Dehydrogenase
/
Neutrophils
/
Nitrites
Limits:
Animals
/
Humans
Language:
English
Journal:
Rev. argent. microbiol
Journal subject:
Microbiology
Year:
2000
Type:
Article
Affiliation country:
Argentina
Institution/Affiliation country:
University of Buenos Aires/AR
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