Abstract
The effect of quinine, primaquine, quinacrine and chloroquine on substrate oxidation and oxidative phosphorylation was studied in isolated Tetrahymena pyriformis mitochondria. Primaquine and chloroquine stimulated the oxidation of succinate and inhibited oxidative phosphorylation, which indicates that these antimalarials act as uncoupling agents. This activity apparently requires both the quinoline nucleus and the diamino alkane side-chain since neither quinine, which contains only the quinoline nucleus, nor quinacrine, which contains only the side-chain, had a significant effect on oxidative phosphorylation or the oxidation of succinate. Primaquine, chloroquine and quinine inhibited the oxidation of fumarate, malate, β-hydroxybutyrate and glutamate, but had little effect when isocitrate, citrate, or α-ketoglutarate were used as substrates. Since primaquine and chloroquine stimulate electron transfer with succinate, these results indicate an inhibition of the enzyme systems which oxidize these substrates. Otherwise, an increased respiratory rate would have been observed upon addition of primaquine or chloroquine. The pattern of inhibition was similar for all three antimalarials and may be because of the quinoline moiety common to these drugs. Quinacrine had no significant effect on any of these reactions.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
