In determining structure–activity relationships, it is advantageous if binding constants for a variety of ligands to a given target molecule can be directly obtained from a single aqueous solution containing a mixture of ligands and the target molecule. In this paper further evidence is provided showing that electrospray ionization mass spectrometry (ESI-MS) can be used in the rapid quantitative analysis of mixtures of vancomycin-group antibiotics and their bacterial cell-wall receptors allowing the identification of even subtle differences in binding constants. Differences in affinities are quantified for a mixture of vancomycin antibiotics (vancomycin, dechlorovancomycin and N-demethylvancomycin) and for a mixture of ristocetin A and its pseudoaglycone. Binding constants determined by ESI-MS were found to be in close agreement with those determined by more direct methods in aqueous solution.
在确定结构-活性关系时,如果可以从含有
配体和目标分子混合物的单一
水溶液中直接获得各种
配体与给定目标分子的结合常数,则是有利的。本文提供的进一步证据表明,电喷雾电离质谱 (ESI-MS) 可用于
万古霉素类抗生素及其细菌细胞壁受体混合物的快速定量分析,从而能够识别结合常数的细微差异。对
万古霉素抗生素混合物(
万古霉素、去
氯万古霉素和 N-去甲基
万古霉素)以及
瑞斯托菌素 A 及其假苷元的混合物的亲和力差异进行定量。发现通过 ESI-MS 测定的结合常数与在
水溶液中通过更直接的方法测定的结合常数非常一致。