title: Redox metabolism in mitochondria of trypanosomatids.
abstract: CONCLUSIONS
  In the single mitochondrion of protozoan trypanosomatid parasites there are several sites for the generation and elimination of reactive oxygen species (ROS), a class of molecules that exhibit a dual role in cells, either as regulatory mediators or as cytotoxic effectors.
  
  
  BACKGROUND
  Formation of ROS in trypanosomatid mitochondria can be induced by various drug compounds. Importantly, it can also be triggered by specific physiologic stimuli, indicating that this phenomenon may occur in living parasites as well. Elimination of ROS in these organelles is attributed to the activity of two iron-dependent superoxide dismutases (FeSODs) and up to three different peroxidases (a cytochrome c peroxidase and two thiol peroxidases).
  
  
  RESULTS
  Data regarding the formation of ROS in trypanosomatid mitochondria are limited and nonsystematic. Another critical issue refers to the exact contribution of mitochondrial FeSODs and peroxidases for ROS removal, given that their antioxidant activity is not essential when abrogated individually. This suggests some level of functional overlapping or that ROS produced in mitochondria under normal conditions can be removed noncatalytically. Also still unsolved is the mechanism by which mitochondrial thiol peroxidases are regenerated to their reduced (active) form.
  
  
  CONCLUSIONS
  The production of intramitochondrial ROS under physiologic conditions and their implication in parasite biology should be further clarified. The relative importance of enzymatic versus nonenzymatic mechanisms for ROS elimination in trypanosomatid mitochondria also requires investigation. Simultaneous depletion of several redundant antioxidant enzymes and determination of noncatalytic antioxidants are possible ways to achieve this.
authors.affiliation: IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal. atomas@ibmc.up.pt
authors.forename: Ana M
authors.initials: AM
authors.lastname: Tomás
authors.forename: Helena
authors.initials: H
authors.lastname: Castro
mesh_terms: D000818:Animals; D004579:Electron Transport; D006801:Humans; D008928:Mitochondria / Q000378:metabolism*; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000502:physiology; D015800:Protozoan Proteins / Q000502:physiology; D017382:Reactive Oxygen Species / Q000378:metabolism; D014345:Trypanosoma / Q000378:metabolism*; D014352:Trypanosomiasis / Q000469:parasitology
chemical_list: D015800:Protozoan Proteins; D017382:Reactive Oxygen Species; D010088:Oxidoreductases