The mitochondrial phosphate carrier reconstituted in liposomes is inhibited by doxorubicin

Abstract

The phosphate carrier has been isolated from beef heart mitochondria in the presence of cardiolipin and reconstituted in asolectin vesicles. It has been found that 100 μM doxorubicin and 100 μM Br‐daunomycin inhibit the unidirectional phosphate uptake in the reconstituted liposomes to the same extent as N‐ethylmaleimide. The inhibition by Br‐daunomycin is not due to covalent interaction with the carrier. The specific interaction between doxorubicin and cardiolipin is responsible for the inhibition of the phosphate carrier. Br‐daunomycin interacts with 3 mitochondrial proteins of apparent M _r ∼45 000, ∼35 000 and ∼30 000.