Bolard Jacques, Cleary John D, Kramer Robert E
Université Pierre et Marie Curie, Paris, France.
J Antimicrob Chemother. 2009 May;63(5):921-7. doi: 10.1093/jac/dkp059. Epub 2009 Mar 3.
Based on the assertion that fluorescence spectroscopy detects dimers of the polyene antibiotic amphotericin B (AmB), this technique was recently proposed to analyse the interaction of the drug with cell membranes. However, contradictory results indicate that this 'dimeric' fluorescence might actually originate from polyene impurities. We used a highly purified AmB to challenge this last proposal.
Comparison of the fluorescence of AmB from different origins was made in dimethyl sulphoxide (DMSO); concentration and sodium dodecyl sulphate (SDS) addition dependencies were analysed in water.
Excitation of fluorescence in the absorption band of the AmB monomer (around 410 nm) revealed no difference between the different samples, in contrast with what was observed by excitation in the absorption wavelengths of self-associated AmB (around 325 nm). Furthermore, in this latter case, no concentration dependence was observed, in DMSO or in water. SDS addition increased the fluorescence in water.
The fluorescence of AmB observed by excitation in the absorption wavelengths of self-associated species (around 325 nm) is explainable by the presence of impurities. Fluorescence is probably not appropriate for characterization of the drug interaction with cell membranes.
基于荧光光谱法可检测多烯抗生素两性霉素B（AmB）二聚体这一论断，该技术最近被用于分析药物与细胞膜的相互作用。然而，相互矛盾的结果表明，这种“二聚体”荧光可能实际上源自多烯杂质。我们使用高纯度的AmB对这一最新观点提出质疑。
在二甲基亚砜（DMSO）中比较不同来源的AmB的荧光；在水中分析浓度和添加十二烷基硫酸钠（SDS）的依赖性。
在AmB单体的吸收带（约410 nm）激发荧光，不同样品之间未观察到差异，这与在自缔合AmB的吸收波长（约325 nm）激发时所观察到的情况相反。此外，在后一种情况下，在DMSO或水中均未观察到浓度依赖性。添加SDS会增加水中的荧光。
在自缔合物质的吸收波长（约325 nm）激发时观察到的AmB荧光可由杂质的存在来解释。荧光可能不适用于表征药物与细胞膜的相互作用。
