Characterization of the binding of amphotericin B to Saccharomyces cerevisiae and relationship to the antifungal effects.
Based on the enhanced fluorescence of amphotericin B in acid solutions, a quantitative assay for this polyene antibiotic has been developed that is sensitive and linear in the range of 0.1 to 10.0 muM. The binding of amphotericin B to Saccharomyces cerevisiae was assayed under various conditions as the amount bound to cells in a dialysis chamber or after centrifugation. Two types of binding were defined: weak, reversible binding occurred at 0 C or higher temperatures and even in the presence of inhibitors of energy metabolism, whereas strong, irreversible binding did not occur at 0 C and was inhibited when energy metabolism was blocked. Only strong binding was correlated with cell killing. Weak binding probably involves the outer layer of the membrane; strong binding probably requires disruption of hydrophobic regions of the cell membrane.
D000666:Amphotericin B / Q000378:metabolism* / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects; D003956:Dialysis; D004734:Energy Metabolism / Q000187:drug effects; D007700:Kinetics; D012441:Saccharomyces cerevisiae / Q000378:metabolism*
D000666:Amphotericin B