Fetuin is an abundant blood protein that participates in multiple biological processes, including the transport and regulation of calcium. Fetuin is also known to have a high affinity for uranium (as the uranyl dioxo cation) and plutonium, thus it has been suggested as one of the main endogenous chelating biomolecules involved in the transport of actinides following an internal uptake event. Nevertheless, no direct measurements of its affinity for f-elements beside these two actinides have been reported. Here, we investigate the interaction between fetuin and trivalent lanthanides, such as samarium, europium, terbium, and dysprosium, by mass spectrometry and fluorescence spectroscopy. Mass spectrometry results indicated that fetuin has four metal binding sites for the metal ions studied. Upon formation, the metal–protein complexes showed luminescence emission as a result of antenna sensitization of the metal ions, whose photophysics were characterized and exploited to perform direct spectrofluorimetric titrations. Furthermore, the thermodynamic constants were calculated for all complexes, confirming the formation of stable complexes with log \({\beta }_{4}^{^{\prime}}\) values between 26 and 27. In characterizing the affinity of the serum protein fetuin for several f-elements, this study expands upon the initial findings focused on uranyl and plutonium, and contributes to a better understanding of the internal distribution and deposition of lanthanides, potentially representative of trivalent actinides.

胎球蛋白是一种丰富的血液蛋白，它参与多种生物过程，包括钙的运输和调节。胎球蛋白也已知对铀（作为铀酰二氧代阳离子）和p具有高亲和力，因此已被建议作为内部吸收事件后参与act系元素运输的主要内源性螯合生物分子之一。然而，除了这两个act系元素外，没有直接测量其对f元素的亲和力的报道。在这里，我们通过质谱和荧光光谱研究胎球蛋白和三价镧系元素（如sa，euro，ter和）之间的相互作用。质谱结果表明胎球蛋白对所研究的金属离子具有四个金属结合位点。形成后 金属-蛋白质复合物显示出发光，这是由于金属离子的天线敏化的结果，该金属离子的光物理特性得到了表征并被利用来进行直接荧光分光滴定。此外，计算了所有配合物的热力学常数，证实了形成稳定配合物的log\（{\ beta} _ {4} ^ {^ {\ prime}} \）的值介于26和27之间。在表征血清蛋白胎蛋白对几种f元素的亲和力时，这项研究扩展了最初的研究重点铀酰和p，有助于更好地理解镧系元素（可能代表三价，系元素）的内部分布和沉积。