[Inhibitory action of Fenton systems on topoisomerase I from Trypanosoma cruzi and Crithidia fasciculata]]. 2003

D Podesta, and S H Fernandez Villamil, and A O Stoppani
Centro de Investigaciones Bioenergéticas (CONICET), Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155, 1121 Buenos Aires, Argentina.

Fenton systems (H2O2/Fe(II) or H2O2/Cu(II)) inhibited Trypanosoma cruzi and Crithidia fasciculata topoisomerase I activity. About 61-71% inactivation was produced by 25 mM Fe(II) or Cu(II) with 3 mM H2O2. Thiol compounds and free radicals scavengers prevented the Fenton systems effects, depending on the topoisomerase assayed. With the T. cruzi enzyme, reduced glutathione, DL-dithiothreitol, cysteine and N-acetyl-L-cysteine entirely prevented the effect of the H2O2/Fe(II) system, mannitol protected 37%, whereas histidine and ethanol were ineffective. With C. fasciculata topoisomerase, reduced glutathione, DL-dithiothreitol and N-acetyl-L-cysteine protected 100%, cysteine, histidine and mannitol protected 28, 34 and 48% respectively, whereas ethanol was ineffective. With the H2O2/Cu(II) system and T. cruzi topoisomerase, DL-dithiothreitol and histidine protected 100% and 60%, respectively but the other assayed protectors were less effective. Similar results were obtained with the C. fasciculata enzyme. Topoisomerase inactivation by H2O2/Fe(II) or H2O2/Cu(II) systems was irreversible since they were not reverted by the more effective enzyme protectors. It is suggested that topoisomerases could act either as scavengers of "reactive oxygen species" (ROS) generated by Fenton systems or bind the corresponding metal ions, whose redox cycling would generate reactive oxygen species "in situ".

UI MeSH Term Description Entries
D007501 Iron A metallic element with atomic symbol Fe, atomic number 26, and atomic weight 55.85. It is an essential constituent of HEMOGLOBINS; CYTOCHROMES; and IRON-BINDING PROTEINS. It plays a role in cellular redox reactions and in the transport of OXYGEN. Iron-56,Iron 56
D010084 Oxidation-Reduction A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471). Redox,Oxidation Reduction
D002614 Chelating Agents Chemicals that bind to and remove ions from solutions. Many chelating agents function through the formation of COORDINATION COMPLEXES with METALS. Chelating Agent,Chelator,Complexons,Metal Antagonists,Chelators,Metal Chelating Agents,Agent, Chelating,Agents, Chelating,Agents, Metal Chelating,Antagonists, Metal,Chelating Agents, Metal
D004791 Enzyme Inhibitors Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction. Enzyme Inhibitor,Inhibitor, Enzyme,Inhibitors, Enzyme
D006861 Hydrogen Peroxide A strong oxidizing agent used in aqueous solution as a ripening agent, bleach, and topical anti-infective. It is relatively unstable and solutions deteriorate over time unless stabilized by the addition of acetanilide or similar organic materials. Hydrogen Peroxide (H2O2),Hydroperoxide,Oxydol,Perhydrol,Superoxol,Peroxide, Hydrogen
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D013045 Species Specificity The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species. Species Specificities,Specificities, Species,Specificity, Species
D013439 Sulfhydryl Reagents Chemical agents that react with SH groups. This is a chemically diverse group that is used for a variety of purposes. Among these are enzyme inhibition, enzyme reactivation or protection, and labelling. SH-Reagents,Sulfhydryl Compound Antagonists,Sulfhydryl Compound Inhibitors,Thiol Reagents,Sulfhydryl Compounds Antagonists,Sulfhydryl Compounds Inhibitors,Antagonists, Sulfhydryl Compound,Antagonists, Sulfhydryl Compounds,Compound Antagonists, Sulfhydryl,Compound Inhibitors, Sulfhydryl,Inhibitors, Sulfhydryl Compound,Inhibitors, Sulfhydryl Compounds,Reagents, Sulfhydryl,Reagents, Thiol,SH Reagents
D014349 Trypanosoma cruzi The agent of South American trypanosomiasis or CHAGAS DISEASE. Its vertebrate hosts are man and various domestic and wild animals. Insects of several species are vectors. Trypanosoma cruzus,cruzi, Trypanosoma
D015800 Protozoan Proteins Proteins found in any species of protozoan. Proteins, Protozoan

Related Publications

D Podesta, and S H Fernandez Villamil, and A O Stoppani
January 2003, Redox report : communications in free radical research,
D Podesta, and S H Fernandez Villamil, and A O Stoppani
August 1969, Comparative biochemistry and physiology,
D Podesta, and S H Fernandez Villamil, and A O Stoppani
January 1993, Biochemistry and molecular biology international,
D Podesta, and S H Fernandez Villamil, and A O Stoppani
May 1984, The Journal of protozoology,
D Podesta, and S H Fernandez Villamil, and A O Stoppani
June 1987, Molecular and biochemical parasitology,
D Podesta, and S H Fernandez Villamil, and A O Stoppani
January 1980, Medicina,
D Podesta, and S H Fernandez Villamil, and A O Stoppani
February 1989, Biochemistry international,
D Podesta, and S H Fernandez Villamil, and A O Stoppani
March 1980, Journal of general microbiology,
D Podesta, and S H Fernandez Villamil, and A O Stoppani
September 1982, Molecular and biochemical parasitology,
D Podesta, and S H Fernandez Villamil, and A O Stoppani
October 1985, Journal of submicroscopic cytology,
Copied contents to your clipboard!