INHIBITION OF SUCCINIC-DEHYDROGENASE AND F0F1-ATP SYNTHASE BY 4,4'-DIISOTHIOCYANATOSTILBENE-2,2'-DISULFONIC ACID (DIDS)

This study shows that incubation of rat liver mitochondria in the pres ence of the thiol/amino reagent 4,4-diisothiocyanatostilbene-2,2'-disu lfonic acid (DIDS) is followed by inhibition of both succinate support ed respiration and oxidative phosphorylation, Half-maximal inhibition of succinic dehydrogenase activity and succinate oxidation by mitochon dria was attained at 55.3 and 60.8 mu M DIDS, respectively. DIDS did i nhibit the net ATP synthesis and ATP double left right arrow [P-32]Pi exchange reaction catalyzed by submitochondrial particles in a dose-de pendent manner (K-i = 31.7 mu M and K-i = 32.7 mu M), respectively. Th e hydrolytic activities of uncoupled heart submitochondrial particles and purified F-1-ATPase were also inhibited 50% by 31.9 and 20.9 mu M DIDS, respectively.