Inhibition of valinomycin-induced

The osmoticum used had a marked effect on the inhibitory potency of FCCP and the non-carbanilates (Table IV). For the non-carbanilate herbicides and FCCP, valinomycin-induced swelling of mitochondria suspended in isotonic KCl was inhibited at much lower concentrations of the herbicides than when the mitochondria were suspended in isotonic KSCN. For the carbanilates, the molar concentration for 50% inhibition of valinomycin-induced swelling of mitochondria suspended in KSCN was about twice the... 

Inhibition of valinomycin-induced swelling of intact spinach chloroplasts, spinach thylakoids, and mung bean mitochondria by FCCP, selected herbicides, and carbanilates. 

Dose/response curves were developed from traces such as those shown in Figure 2 for dinoseb. For comparative purposes, the concentration of compound required to induce an increase in the swelling rate of 0,02 A in 1 min relative to the no-herbicide controls is shown in Table V for chloroplasts, thylakoids, and mitochondria, Thylakoids did not swell as extensively as the other two organelles, consequently, the values are for a change of 0,01 A, The relative order of activity shown by the compounds is similar to that given in Table IV for inhibition of valinomycin-induced swelling in the three organelles. 

As for inhibition of valinomycin-induced swelling, some of the carbanilates (3-CHPC and 2,3-DCIPC) seem to be acting differently in that values obtained in isotonic KCl were lower than those obtained in isotonic KSCN,... 

Figure 1. Representative traces of absorbance changes that show inhibition by dinoseb of valinomycin-induced swelling of intact spinach chloroplasts (B), spinach thylakoids (C), and mung bean mitochondria (D) suspended in isotonic KSCN. The model system is presented diagrammatically in A. Swelling was initiated by the addition of 0.1 /xM valinomycin (VAL),...

Figure 3. Diagrammatic models and representative traces of absorbance changes that show the kinetics and inhibition by quercetin (Quer.) of (A) valinomycin-induced swelling of mung mitochondria suspended in isosmotic KCl (B) swelling of mung bean mitochondria suspended in isosmotic ammonium phosphate and (C) swelling of mung bean mitochondria suspended in isosmotic prollne.

Attempts to measure ATP-induced ApH formation in these reconstituted liposomes were unsuccessful (Dewey, Hammes, 1981 Shahak, Pick, 1983). We considered the possibility that residues of ammonium, carried over with the enzyme from the (NH4)2S04 percipitation step, were responsible for inhibiting the formation of ApH, by buffering the protons transported into the liposomes. This will inhibit the formation of ApH while facilitating Aifj formation. Indeed, removing the ammonium by passing the proteoliposomes through a Sephadex column preequilibrated with valinomycin and K, enabled us to measure ATP-dependent ApH formation in CFq-CFj proteoliposomes. 

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