Anderson Shauna L, Rovnyak David, Strein Timothy G
Department of Chemistry, Bucknell University, Lewisburg, Pennsylvania, USA.
Chirality. 2016 Apr;28(4):290-8. doi: 10.1002/chir.22580. Epub 2016 Feb 22.
Isothermal titration calorimetry (ITC) is shown to be a sensitive reporter of bile salt micellization and chiral recognition. Detailed ITC characterization of bile micelle formation as well as the chiral recognition capabilities of sodium cholate (NaC), deoxycholate (NaDC), and taurodeoxycholate (NaTDC) micelle systems are reported. The ΔH(demic) of these bile salt micelle systems is directly observable and is strongly temperature-dependent, allowing also for the determination of ΔCp(demic). Using the pseudo-phase separation model, ΔG(demic) and TΔS(demic) were also calculated. Chirally selective guest-host binding of model racemic compounds 1,1'-bi-2-napthol (BN) and 1,1'-binaphthyl-2,2'-diylhydrogenphosphate (BNDHP) to bile salt micelles was then investigated. The S-isomer was shown to bind more tightly to the bile salt micelles in all cases. A model was developed that allows for the quantitative determination of the enthalpic difference in binding affinity that corresponds to chiral selectivity, which is on the order of 1 kJ mol(-1).
等温滴定量热法（ITC）被证明是胆汁盐胶束化和手性识别的灵敏报告方法。本文报道了胆汁胶束形成的详细ITC表征以及胆酸钠（NaC）、脱氧胆酸钠（NaDC）和牛磺脱氧胆酸钠（NaTDC）胶束系统的手性识别能力。这些胆汁盐胶束系统的ΔH（半胶束化）可直接观测到，且强烈依赖于温度，这也使得ΔCp（半胶束化）的测定成为可能。利用假相分离模型，还计算了ΔG（半胶束化）和TΔS（半胶束化）。随后研究了模型外消旋化合物1,1'-联-2-萘酚（BN）和1,1'-联萘基-2,2'-二氢磷酸酯（BNDHP）与胆汁盐胶束的手性选择性客体-主体结合。结果表明，在所有情况下，S-异构体与胆汁盐胶束的结合更紧密。开发了一个模型，该模型能够定量测定与手性选择性相对应的结合亲和力的焓差，其量级为1 kJ mol⁻¹。
