Synthesis of lanthanide(III) complexes appended with a diphenylphosphinamide and their interaction with human serum albumin
作者:Marco Giardiello、Mauro Botta、Mark P. Lowe
DOI:10.1007/s10847-011-0009-4
日期:2011.12
Two DOTA-based proligands bearing a pendant diphenylphosphinamide 4a and 4b were synthesised. Their Eu(III) complexes exhibit sensitised emission when excited at 270 nm via the diphenylphosphinamide chromophore. Hydration states of q = 1.5 were determined from excited state lifetime measurements (Eu.4a $$ k_\textH}}_ 2} \textO}}}} = 2. 1 4 \,\textms}}^ - 1} ,\;k_\textD}}_ 2} \textO}}}} = 0. 6 4 \,\textms}}^ - 1} $$ ; Eu.4b $$ k_\textH}}_ 2} \textO}}}} = 2. 6 7\, \textms}}^ - 1} ,\;k_\textD}}_ 2} \textO}}}} = 1. 1 8 \,\textms}}^ - 1} $$ ). In the presence of human serum albumin (HSA) (0.1 mM Eu.4a/b, 0.67 mM HSA, pH 7.4) q = 0.4 for Eu.4a ( $$ k_\textH}}_ 2} \textO}}}} = 1. 3 4\, \textms}}^ - 1} ,\;k_\textD}}_ 2} \textO}}}} = 0. 7 5\, \textms}}^ - 1} $$ ) and q = 0.6 for Eu.4b ( $$ k_\textH}}_ 2} \textO}}}} = 1. 8 3\, \textms}}^ - 1} ,\;k_\textD}}_ 2} \textO}}}} = 1.0 5 \,\textms}}^ - 1} $$ ). Relaxivites (pH 7.4, 298 K, 20 MHz) of the Gd(III) complexes in the absence and presence of HSA (0.1 mM Gd.4a/b, 0.67 mM HSA) were: Gd.4a (r 1 = 7.6 mM−1s−1 and r 1 = 11.7 mM−1s−1) and Gd.4b. (r 1 = 7.3 mM−1s−1 and r 1 = 16.0 mM−1s−1). These relatively modest increases in r 1 are consistent with the change in inner-sphere hydration on binding to HSA shown by luminescence measurements on Eu.4a/b. Binding constants for HSA determined by the quenching of luminescence (Eu) and enhancement of relaxivity (Gd) were Eu.4a (27,000 M−1 ± 12%), Eu.4b (32,000 M−1 ± 14%), Gd.4a (21,000 M−1 ± 15%) and Gd.4b (26,000 M−1 ± 15%).
合成了两种带有二苯基膦酰胺 4a 和 4b 侧链的基于 DOTA 的前配体。当通过二苯基膦酰胺发色团在 270 nm 处激发时,它们的 Eu(III) 配合物表现出敏化发射。 q = 1.5 的水合状态是根据激发态寿命测量确定的 (Eu.4a $$ k_\textH}}_ 2} \textO}}}} = 2. 1 4 \, \textms}}^ - 1} ,\;k_\textD}}_ 2} \textO}}}} = 0. 6 4 \,\textms} }^ - 1} $$ ; Eu.4b $$ k_\textH}}_ 2} \textO}}}} = 2. 6 7\, \textms} }^ - 1} ,\;k_\textD}}_ 2} \textO}}}} = 1. 1 8 \,\textms}}^ - 1 } $$ )。在存在人血清白蛋白 (HSA) 的情况下(0.1 mM Eu.4a/b、0.67 mM HSA,pH 7.4),Eu.4a 的 q = 0.4 ( $$ k_\textH}}_ 2} \textO}}}} = 1. 3 4\, \textms}}^ - 1} ,\;k_\textD}}_ 2} \textO }}}} = 0. 7 5\, \textms}}^ - 1} $$ ) 和 q = 0.6 对于 Eu.4b ( $$ k_\textH}}_ 2 } \textO}}}} = 1. 8 3\, \textms}}^ - 1} ,\;k_\textD}}_ 2} \text O}}}} = 1.0 5 \,\textms}}^ - 1} $$ )。在不存在和存在 HSA(0.1 mM Gd.4a/b、0.67 mM HSA)的情况下,Gd(III) 复合物的松弛活性(pH 7.4、298 K、20 MHz)为:Gd.4a (r 1 = 7.6 mM− 1s−1 和 r 1 = 11.7 mM−1s−1) 和 Gd.4b。 (r 1 = 7.3 mM−1s−1 且 r 1 = 16.0 mM−1s−1)。 r 1 的这些相对适度的增加与 Eu.4a/b 上的发光测量显示的与 HSA 结合的内球水合作用的变化一致。通过发光淬灭 (Eu) 和弛豫增强 (Gd) 确定的 HSA 结合常数为 Eu.4a (27,000 M−1 ± 12%)、Eu.4b (32,000 M−1 ± 14%)、Gd.4a (21,000 M−1 ± 15%) 和 Gd.4b (26,000 M−1 ± 15%)。