Gd(DTPA-BIN)的热力学性质及与牛血清白蛋白作用的NMR研究

NMR STUDIES OF Gd(DTPA-BIN) IN BOVINE SERUM ALBUMIN SOLUTION AND ITS THERMODYNAMIC PROPERTIES

报道了一种新合成的DTPA酰胺类衍生物DTPA－BIN的质子解离过程，其质子化常数总和与稳定性大于DTPA－BMA并采用核磁共振弛豫分析法研究了Gd（DTPA、BIN）在水溶液和牛血清白蛋白溶液中的诱导弛豫增强性质．Gd（DTPA－BIN）配合物在水溶液中弛豫效率为3.28mmol－1·L-1。牛血清白蛋白分子可以与Gd（DTP－BIN）配合物非共价地结合，这种非共价结合体的旋转相关时间明显长于自由配合物，使Gd（DTPA－BIN）在蛋白质溶液中弛豫效率增高．本文结果表明弛豫增强方法可以用来研究顺磁性金属配合物与蛋白质之间的相互作用情况．

Diethylene-triaminopentaacetate his(isoniazid) (Gd(DTPA-BIN) ) was synthesised as acontrast agent for magnetic resonance imaging (MRI). The protonation process of DTPABIN was proposed in the order of the central amine, the terminal ammes, the central carboxyl, the terminal carboxyl, the other terminal carboxyl and central amine. Based on 1HNMR titration analysis, the sum of the protonation constants for DTPA-BIN is obviouslyhigher than that of DTPA-BMA, which might reflect that the stability of Gd(DTPA-BIN)would be higher than Gd(DTPA-BMA). The water relaxation enhancement behavior of Gd(DTPA-BIN) in aqueous and in BSA solution has been studied. The results indicate that Gd(DTPA-BIN) can integrate non-covalently with BSA mainly in forms of (Gd(DTPA-BIN) ) BSA and (Gd (DTPA-BIN))2 BSA for which the apparent equilibrium constants are0. 0149mmol-1 L and 0. 00326mmol-2 L2 respectively. This method would be used tostudy the interactivities between protein and contrast agent.