尖吻蝮蛇蛇毒中纤溶组分与铽的相互作用

Intraction between Tb^(3+) and Fibrinolytic Principle from Agkistrodon Acutus Venom

利用平衡透析、原子吸收、荧光滴定和荧光寿命测定等方法确定了皖南尖吻蝮蛇蛇毒纤溶组分（FP）中Ca（2+）含量，并利用荧光光谱研究了Tb（3+）与FP中色氨酸（Trp）残基之间能量转移和FP中的微区结构。结果表明，每个FP分子中只含有一个Ca(2+)；Tb(3+)可完全取代FP中的Ca(2+)，FP中的Trp残基可将能量转移到结合在FP中的Tb(3+)上；研究还测得Tb(3+)与FP中Trp残基之间的距离约为0．375nm。

By using equilibrium dialysis, atomic absorption spectrometry, fluorescence titration anddetermination of fluorescence lifetime, it can be followed that each fibrinolytic principle(FP)molecule contains one Ca2+ -binding site and one Ca2+. Energy transfer between Tb3+ and theTrp residue in FP was studied through fluorescence spectroscopy. The results show that theCa2+ in a FP molecule can be substitute by a Tb3+. In FP molecule, the excition energy can betransferred from the Trp residue as an energy donor to the Tb3+ as an acceptor, and substitutedinto FP and located near the Trp residue. The distance between Tb3+ and the Trp residue, a0.375 urn, is worked out with the experimental data and Forster theory.