NUMBER OF INNER-SPHERE WATER-MOLECULES IN GD-3+ AND EU-3+ COMPLEXES OF DTPA-AMIDE AND DTPA-ESTER CONJUGATES
NUMBER OF INNER-SPHERE WATER-MOLECULES IN GD-3+ AND EU-3+ COMPLEXES OF DTPA-AMIDE AND DTPA-ESTER CONJUGATES
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DOI：
10.1002/mrm.1910080209
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发表时间：
1988-10-01
影响因子：
3.3
通讯作者：
SPILLER, M
中科院分区：
文献类型：
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作者：
GERALDES, CFGC;SHERRY, AD;SPILLER, M
使用磷光寿命和核磁弛豫色散 (NMRD) 测量研究了 Eu3+ 和 Gd3+ 与五种 DTPA 类似物复合的内球水配位数，其中一个或两个末端羧酸基团被功能化为丙基酰胺或丙酯。两种方法均表明水配位数的增加并未超过类似 DTPA 配合物观察到的值。磷光寿命结果表明，所有五种Eu3+配合物在25℃下都有一个内层水分子。 C. 三种 Gd3+ 配合物在 25°C 的 NMRD 曲线。 C 也与一个内球水分子一致，而两种复合物的轮廓仅与复合物的混合物一致，其中 50% 含有单个水分子，50% 不含单个水分子。降低温度会改变这些物种的数量，使得所有五种 Gd3+ 复合物在 5°C 时平均结合水显着减少。 C. 这些结果解释了先前报道的 Gd(DTPA)-蛋白质缀合物的 NMRD 曲线的异常温度依赖性。我们认为 Gd(DTPA)-共轭体系具有流变配位层，其中内层配位水的量在 5° 时从接近零变化到 5° 时接近零。 C 至 37 度附近的最高温度 2。 C.
The inner-sphere water coordination number for Eu3+ and Gd3+ complexed with five DTPA analogs, in which one or two terminal carboxylate groups are functionalized as propyl amides or propyl esters, have been studied using phosphorescence lifetime and nuclear magnetic relaxation dispersion (NMRD) measurements. Both methods show that the water coordination number does not increase above that observed for the analogous DTPA complexes. The phosphorescence lifetime results indicate that all five Eu3+ complexes have one inner-sphere water molecule at 25.degree. C. The NMRD profiles for three of the Gd3+ complexes at 25.degree. C are also consistent with one inner-sphere water molecule, whereas two complexes have profiles consistent only with a mixture of complexes, 50% containing a single water molecule and 50% with none. Lowering the temperature alters the population of these species such that all five Gd3+ complexes have significantly less bound water on average at 5.degree. C. These results explain the anomalous temperature dependencies of the NMRD curves reported previously for the Gd(DTPA)-protein conjugates. We suggest that he Gd(DTPA)-conjugate systems have a fluxional coordination sphere whereby the amount of inner-sphere coordinated water varies from near zero at 5.degree. C to a high of two near 37.degree. C.