Table IV.

Sensitivity of citrate exchange in reconstituted liposomes to inhibitors

Addition	Concentration	Inhibition
	mm	%
Mersalyl	0.5	91
p-Hydroxymercuribenzoate	0.5	85
N-Ethylmaleimide	2.0	4
Benzylmalonate	2.0	55
Butylmalonate	2.0	58
1,2,3-Benzenetricarboxylate	2.0	45
1,2,4-Benzenetricarboxylate	2.0	5
Atractyloside	0.1	18
Phenylglyoxal	10.0	15
Phenylisothiocyanate	10.0	97
Pyridoxal 5′-P	10.0	100

The proteoliposomes were loaded with 20 mm citrate and the exchange was started by adding 0.1 mm [¹⁴C]citrate. The inhibitors were added together with [¹⁴C]citrate except the −SH reagents, which were added 2 min before the labeled substrate. The data are the means of three experiments. The control value of uninhibited citrate exchange was 6127 nmol 10 min⁻¹ mg⁻¹ protein.