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Activation of alternative oxidase and uncoupling protein lowers hydrogen peroxide formation in amoeba Acanthamoeba castellanii mitochondria
Author(s) -
Czarna Malgorzata,
Jarmuszkiewicz Wieslawa
Publication year - 2005
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2005.04.081
Subject(s) - hydrogen peroxide , alternative oxidase , amoeba (genus) , mitochondrion , chemistry , biochemistry , microbiology and biotechnology , biology
Mitochondria of amoeba Acanthamoeba castellanii were used to determine the role of two energy‐dissipating systems, i.e., a free fatty acid (FFA)‐activated, purine nucleotide‐inhibited uncoupling protein (AcUCP) and a FFA‐insensitive, purine nucleotide‐activated ubiquinol alternative oxidase (AcAOX), in decreasing reactive oxygen species production in unicellular organisms. It is shown that the activation of AcUCP by externally added FFA resulted in a strong decrease in H 2 O 2 production, whilst the inhibition of the FFA acid‐induced AcUCP activity by GDP or addition of bovine serum albumin (BSA) enhanced production of H 2 O 2 . Similarly, the activation of antimycin‐resistant AcAOX‐mediated respiration by GMP significantly lowered H 2 O 2 production, while inhibition of the oxidase by benzohydroxamate cancelled the GMP‐induced effect on H 2 O 2 production. When active together, both energy‐dissipating systems revealed a cumulative effect on decreasing H 2 O 2 formation. The results suggest that protection against mitochondrial oxidative stress may be a physiological role of AOX and UCP in unicellulars, such as A. castellanii .