atractyloside and agaric-acid

In this work, we studied the effect of N-ethylmaleimide on permeability transition. The findings indicate that the amine inhibited the effects of carboxyatractyloside and agaric acid. It is known that these reagents interact with the adenine nucleotide carrier through the cytosolic side. When oleate, which interacts through the matrix side, was used it was found that the amine amplified the effects of oleate on permeability transition. The results also show that N-ethylmaleimide strengthened the inhibition induced by carboxyatractyloside, agaric acid, and oleate on ADP exchange. Furthermore, it was also found that oleate improved the binding of eosin-5-maleimide on the adenine nucleotide translocase.

Topics: Adenosine Diphosphate; Atractyloside; Calcium; Citric Acid; Eosine Yellowish-(YS); Ethylmaleimide; Mitochondria; Mitochondrial ADP, ATP Translocases; Mitochondrial Swelling; Oleic Acid; Permeability

The metabolic inter-relationships between malarial parasites and their host erythrocytes are poorly understood. They have been investigated hitherto mostly by observing parasite behavior in erythrocyte variants, in metabolically altered erythrocytes, or in cell-free in vitro systems. We have studied the interconnection between the bioenergetic metabolism of host and parasite through compartment analysis of ATP in Plasmodium falciparum-infected human red blood cells, using Sendai virus-induced host cell lysis. ATP concentrations in host and parasite compartments were found to be equal. Inhibitors of mitochondrial activity reduce ATP levels to a similar extent in host and parasite compartments, although only the parasite contains functional mitochondria. It is shown that equalization of ATP levels is brought about by means of an adenylate translocator, probably localized at the parasite plasma membrane, in conjunction with adenylate kinase activity detected both in host and parasite compartments. The translocator is inhibited by compounds which are known to inhibit specifically the translocator of the inner membrane of mammalian mitochondria, with identical inhibitory constants. Addition of these inhibitors to intact infected cells causes a rapid depletion of ATP in the host compartment and a parallel increase in the parasite, suggesting that the parasite supplies ATP to its host cell rather than the reverse.

Topics: Adenosine Diphosphate; Adenosine Triphosphate; Adenylate Kinase; Animals; Atractyloside; Cell Membrane; Citrates; Citric Acid; Cytosol; Energy Metabolism; Erythrocytes; Humans; Mitochondria; Mitochondrial ADP, ATP Translocases; Nucleotidyltransferases; Palmitoyl Coenzyme A; Phosphotransferases; Plasmodium falciparum

Topics: Adenosine Triphosphatases; Animals; Atractyloside; Biological Transport, Active; Citric Acid; Dinitrophenols; Kinetics; Mitochondria, Liver; Nucleotidyltransferases; Oxygen Consumption; Phosphates; Rats; Tricarboxylic Acids