title: Effects of equisetin on rat liver mitochondria: evidence for inhibition of substrate anion carriers of the inner membrane.
abstract: The effect of equisetin, an antibiotic produced by Fusarium equiseti, has been studied on mitochondrial functions (respiration, ATPase, ion transport). Equisetin inhibits the DNP-stimulated ATPase activity of rat liver mitochondria and mitoplasts in a concentration-dependent manner; 50% inhibition is caused by about 8 nmol equisetin/mg protein. The antibiotic is without effect either on the ATPase activity of submitochondrial particles or on the purified F1-ATPase. It inhibits both the ADP- or DNP-activated oxygen uptake by mitochondria in the presence of glutamate+malate or succinate as substrates, but only the ADP-stimulated respiration is inhibited if the electron donors are TMPD+ascorbate. It does not affect the NADH or succinate oxidation of submitochondrial particles. Equisetin inhibits in a concentration-dependent manner the active Ca(2+)-uptake of mitochondria energized both by ATP or succinate without affecting the Ca(2+)-uniporter itself. The antibiotic inhibits the ATP-uptake by mitochondria (50% inhibition at about 8 nmol equisetin/mg protein) and the Pi and dicarboxylate carrier. It does not lower the membrane potential at least up to 200 nmol/mg protein concentration. The data presented in this paper indicate that equisetin specifically inhibits the substrate anion carriers of the mitochondrial inner membrane.
authors.affiliation: Department of Biochemistry II, Semmelweis University of Medicine, Budapest, Hungary.
authors.forename: T
authors.initials: T
authors.lastname: König
authors.forename: A
authors.initials: A
authors.lastname: Kapus
authors.forename: B
authors.initials: B
authors.lastname: Sarkadi
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D000838:Anions / Q000378:metabolism*; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism; D002352:Carrier Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D004734:Energy Metabolism / Q000187:drug effects; D007425:Intracellular Membranes / Q000187:drug effects / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects; D008930:Mitochondria, Liver / Q000187:drug effects*; D010101:Oxygen Consumption / Q000187:drug effects; D010710:Phosphates / Q000378:metabolism; D011760:Pyrrolidinones / Q000494:pharmacology; D051381:Rats; D013386:Succinates / Q000378:metabolism; D019802:Succinic Acid; D013764:Tetrahydronaphthalenes; D014475:Uncoupling Agents / Q000494:pharmacology
chemical_list: D000838:Anions; D002352:Carrier Proteins; D010710:Phosphates; D011760:Pyrrolidinones; D013386:Succinates; D013764:Tetrahydronaphthalenes; D014475:Uncoupling Agents; C024509:equisetin; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D019802:Succinic Acid; D000251:Adenosine Triphosphatases; D002118:Calcium