[Effect of polymyxins B and M on oxygen uptake by rat liver mitochondria].
Polycationic peptide antibiotics, polymixins B and M, are studied for their effect on oxygen uptake by rat liver mitochondria. They both inhibit the process at state 3 and 3p according to Chance. Low concentrations of polymixin M do not affect oxygen uptake by mitochondria at state 4, but its high concentrations inhibit it. Concentration dependence of polymixin B effect on mitochondria at state 4 is of a bell-like character. Competitive interrelations are found between polymixins M and B in their effect on mitochondria at state 4. Chromatography reveals differences in peptide mobility in a thin layer. It is supposed that polymixin inhibition of oxygen uptake by mitochondria is associated with a disordering effect of the polymixins on the membrane structure during peptide binding to the lipid phase of the membranes. Low concentrations of polymixin B are likely to promote an increase in membrane permeability of mitochondria at state 4.
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D055598:Chemical Phenomena; D002621:Chemistry; D003864:Depression, Chemical; D066298:In Vitro Techniques; D007425:Intracellular Membranes / Q000187:drug effects*; D008930:Mitochondria, Liver / Q000187:drug effects* / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects*; D011112:Polymyxin B / Q000494:pharmacology; D011113:Polymyxins / Q000494:pharmacology*; D051381:Rats
D011113:Polymyxins; D011112:Polymyxin B
Deĭstvie polimiksinov B i M na pogloshchenie kisloroda mitokhondriiami pecheni krys.