Open AccessInvolvement of the alternative oxidase in respiration of Yarrowia lipolytica mitochondria is controlled by the activity of the cytochrome pathway
Author(s) -
Medentsev Aleksandr G,
Arinbasarova Anna Yu,
Golovchenko Nikolai P,
Akimenko Vassily K
Publication year - 2002
Publication title -
fems yeast research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.991
H-Index - 92
eISSN - 1567-1364
pISSN - 1567-1356
DOI - 10.1111/j.1567-1364.2002.tb00118.x
Subject(s) - cytochrome c oxidase , alternative oxidase , cyanide , biochemistry , cytochrome , ferricyanide , mitochondrion , oxidative phosphorylation , respiratory chain , electron transport chain , cytochrome c , biology , cytochrome c1 , oxidase test , yarrowia , respiration , coenzyme q – cytochrome c reductase , chemistry , enzyme , yeast , organic chemistry , botany
The degree of involvement of cyanide‐resistant alternative oxidase in the respiration of Yarrowia lipolytica mitochondria was evaluated by comparing the rate of oxygen consumption in the presence of cyanide, which shows the activity of the cyanide‐resistant alternative oxidase, and the oxidation rate of cytochrome c by ferricyanide, which shows the activity of the main cytochrome pathway. The oxidation of succinate by mitochondria in the presence of ferricyanide and cyanide was associated with oxygen consumption due to the functioning of the alternative oxidase. The subsequent addition of ADP or FCCP (an uncoupler of oxidative phosphorylation) completely inhibited oxygen consumption by the mitochondria. Under these conditions, the inhibition of the alternative oxidase by benzohydroxamic acid (BHA) failed to affect the reduction of ferricyanide at the level of cytochrome c . BHA did not influence the rate of ferricyanide reduction by the cytochrome pathway occurring in controlled state 4, nor could it change the phosphorylation quotient ATP/O upon the oxidation of various substrates. These data indicate that the alternative system is unable to compete with the cytochrome respiratory chain for electrons. The alternative oxidase only transfers the electrons that are superfluous for the cytochrome respiratory chain.