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在ｐＨ７．４０．１ｍｏｌ／ＬＨｅｐｅｓ及室温条件下，使用荧光光谱进行了Ｔｂ３＋对人血清脱铁转铁蛋白的滴定．结果表明Ｔｂ３＋与人血清脱铁转铁蛋白结合后，其５４９ｎｍ处的荧光强度增强约１０５倍．在５４９ｎｍ处Ｔｂ３＋－脱铁转铁蛋白络合物的摩尔荧光强度是（９．６５±０．０５）×１０４ｍｏｌ－１Ｌ，Ｔｂ３＋可占据脱铁转铁蛋白的两个金属离子结合部位，优先占据脱铁转铁蛋白的Ｃ端结合部位，条件平衡常数是ｌｇＫＣ＝９．９６±０．２０，ｌｇＫＮ＝６．３７±０．１６．Ｔｂ３＋与Ｒ３＋Ｅ（ＲＥ＝Ｎｄ、Ｓｍ、Ｅｕ和Ｇｄ）间的线性自由能关系表明稀土离子占据脱铁转铁蛋白的Ｃ端结合部位时受离子大小的影响
The titration of Tb3 + to human serum transferrin was performed using fluorescence spectroscopy at pH 7.40.1 mol / LHepes and room temperature. The results showed that the fluorescence intensity of Tb3 + at 105 nm increased about 105% after binding to human serum transferrin. The molar fluorescence intensity of Tb3 + -ferrotransferrin complex at (549nm) was (9.65 ± 0.05) × 104mol-1L. Tb3 + could occupy two metal ion binding sites of apo-transferrin. The C-terminal binding site of apo-transferrin has a conditional equilibrium constant of lgKC = 9.96 ± 0.20 and lgKN = 6.37 ± 0.16. The linear free energy relationship between Tb3 + and R3 + E (RE = Nd, Sm, Eu and Gd) shows that rare earth ions are affected by ion size when they occupy the C-terminal binding site of the transferrin