Possible role of the NADH-fumarate reductase in superoxide anion and hydrogen peroxide production in Trypanosoma brucei.
Mitochondrial membranes from Trypanosoma brucei procyclic trypomastigotes generated superoxide anion and hydrogen peroxide in a 2:1 ratio when supplemented with NADH. Fumarate inhibited hydrogen peroxide formation (Ki = 16 microM) with the same affinity as it stimulated NADH-fumarate reductase activity. Superoxide anion production was also 65% inhibited by fumarate (Ki = 20 microM). The KM for NADH of the NADH-fumarate reductase (60 microM) was also similar to that for hydrogen peroxide generation in the absence of fumarate (30 microM). These results suggest that the NADH-fumarate reductase is involved as a source for free radical generation in T. brucei mitochondria.
Turrens
J F
JF
Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD.
D000818:Animals; D003574:Cytochrome c Group / Q000378:metabolism; D005650:Fumarates / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism*; D009243:NAD / Q000378:metabolism; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000378:metabolism*; D044925:Oxidoreductases Acting on CH-CH Group Donors; D010101:Oxygen Consumption; D013481:Superoxides / Q000378:metabolism*; D014346:Trypanosoma brucei brucei / Q000201:enzymology* / Q000378:metabolism
D003574:Cytochrome c Group; D005650:Fumarates; D009243:NAD; D013481:Superoxides; D006861:Hydrogen Peroxide; D010088:Oxidoreductases; D044925:Oxidoreductases Acting on CH-CH Group Donors; C020155:fumarate reductase (NADH)