Pd( Ⅱ)与色氨酸、酪氨酸及苯丙氨酸相互作用的荧光光谱

摘要

The fluorescence of three aromatic amino acids, tryptophan(Tip) , tyrosine(Tyr) and phenylala-nine(Phe) could be quenched by Pd( E ). The changes of absorption spectra, the effect of temperature and the quenching constant ￡5V indicated this procedure was static quenching, which was due to the formation of ground-state complex between Pd( II ) and the amino acids. The results showed that in the presence of certain concentration of Cl- , Pd( II ) coordinated with amino acids by N-N and N-O to form mixed-type ternary complexes Pd(HR)Cl2 (Trp and Phe systems) and Pd( H2R) Cl2 (Tyr system), respectively. This fluorescence system not only can be used in the study on the interaction between Pd ( II ) and aromatic amino acids, but also creates conditions for determining Pd( II ) by amino acid (especially Trp) probe as a sensitive fluorescence quenching method.%当Pd(Ⅱ)与色氨酸(Trp),酪氨酸(Tyr)及苯丙氨酸(Phe)等芳香族氨基酸发生相互作用时,3种氨基酸的荧光均发生猝灭.从吸收光谱的变化、温度对猝灭作用的影响及猝灭常数KgV可以判定该荧光猝灭作用是由于Pd(Ⅱ)与上述氨基酸形成基态配合物而导致的静态猝灭过程.在一定浓度的Cl-存在下,Pd(Ⅱ)与氨基酸分别以N-N配位和N-O配位形成混配型三元配合物Pd (HR) C12 (Trp和Phe体系)和Pd (H,R)C12( Tyr体系),并推测了配合物相应的结构.该荧光猝灭体系不仅可用于研究Pd(Ⅱ)与上述芳香族氨基酸的相互作用,也可成为以氨基酸尤其是Trp为探针用高灵敏荧光猝灭法测定把的基础.