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Mitochondriální cytochrom c oxidasa: inhibice kyanidem a vliv defektu asemblačního faktoru Surf1 / Mitochondrial cytochrome c oxidase: cyanide inhibition and role of assembly factor Surf1 defect

The activity of mitochondrial cytochrome c oxidase (COX) can be affected by either exogenous or endogenous factors. The most efficient and in the environment abundant compound that inhibits COX is cyanide. The very frequent cause of COX deficiency in humans is represented by a defect in the SURF1 gene. The mechanism of cyanide inhibitory effect on COX as well as the conditions for its recovery are not yet fully explained. Three parameters of COX function, namely the transport of electrons (oxygen consumption), the transport of protons (mitochondrial membrane potential, m) and the enzyme affinity to oxygen (p50 value), were studied with regard to the inhibition by KCN and its reversal by pyruvate. The function of COX was analysed in intact isolated rat liver mitochondria, both within the respiratory chain and as a sole enzyme, using succinate or an artificial electron donor ascorbate + TMPD as a substrate. 250 M KCN completely inhibited both electron- and proton-transporting function of COX, and this inhibition was reversible as proved with washing of mitochondria. The addition of 60 mM pyruvate induced the maximal recovery of both parameters to 60 - 80 % of original values. Using KCN in the low concentration range up to 5 M, a profound, 30-fold decrease of COX affinity to oxygen was observed....

Identiferoai:union.ndltd.org:nusl.cz/oai:invenio.nusl.cz:285547
Date January 2010
CreatorsNůsková, Hana
ContributorsKalous, Martin, Drahota, Zdeněk
Source SetsCzech ETDs
LanguageCzech
Detected LanguageEnglish
Typeinfo:eu-repo/semantics/masterThesis
Rightsinfo:eu-repo/semantics/restrictedAccess

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