TY  - JOUR
A1  - Galkin, Alexander
A1  - Brandt, Ulrich
T1  - Superoxide radical formation by pure complex I (NADH:ubiquinone oxidoreductase) from Yarrowia lipolytica
T2  - Journal of biological chemistry
N2  - Generation of reactive oxygen species (ROS) is increasingly recognized as an important cellular process involved in numerous physiological and pathophysiological processes. Complex I (NADH:ubiquinone oxidoreductase) is considered as one of the major sources of ROS within mitochondria. Yet, the exact site and mechanism of superoxide production by this large membrane-bound multiprotein complex has remained controversial. Here we show that isolated complex I from Yarrowia lipolytica forms superoxide at a rate of 0.15% of the rate measured for catalytic turnover. Superoxide production is not inhibited by ubiquinone analogous inhibitors. Because mutant complex I lacking a detectable iron-sulfur cluster N2 exhibited the same rate of ROS production, this terminal redox center could be excluded as a source of electrons. From the effect of different ubiquinone derivatives and pH on this side reaction of complex I we concluded that oxygen accepts electrons from FMNH or FMN semiquinone either directly or via more hydrophilic ubiquinone derivatives.
Y1  - 2005
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/76202
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-762027
SN  - 0021-9258
VL  - 280
IS  - 34
SP  - 30129
EP  - 30135
PB  - American Society for Biochemistry and Molecular Biology Publications
CY  - Bethesda, Md
ER  -