Georgiou S, Christofidis I
Immunoassay Quality Control Laboratory, Institute of Radioisotopes and Radiodiagnostic Products, Athens, Greece.
J Immunoassay. 1996 Feb;17(1):47-66. doi: 10.1080/01971529608005778.
In this work we studied the effects of the molecular weight (M.W.) of thyroxin (T4)-conjugates and the sample dilution factor on the binding potential (C) of serum T4-binding proteins for these T4-conjugates. We prepared six T4-conjugates with great difference in molecular weight with proteins such as IgG, apoferritin, ferritin, transferrin, and thyroglobulin using p-benzoquinone as bifunctional reagent. The conjugates prepared were characterized in terms of their M.W., the molar ratio of T4 to the carrier protein, and their affinity to bind with the anti-Tr antibody. The binding potential values of serum T4-binding proteins for the T4-conjugates were determined, following appropriate mathematical interpretation of the results, obtained through an assay system containing 125I-labeled conjugated tracers, anti-T4 antibody in great excess compared with the concentration of the tracers, and increasing concentration of T4-binding proteins. We conclude that the M.W. of the conjugates is a parameter which significantly influences the binding of a conjugate to the T4-binding proteins. Additionally, for conjugates of very high M.W. (> 650,000), zero C values were obtained using 20-fold sample dilution in the final incubation mixture.
在本研究中，我们探讨了甲状腺素（T4）-缀合物的分子量（M.W.）以及样品稀释倍数对血清T4结合蛋白与这些T4-缀合物结合潜力（C）的影响。我们使用对苯醌作为双功能试剂，制备了六种分子量差异很大的T4-缀合物，载体蛋白包括IgG、脱铁铁蛋白、铁蛋白、转铁蛋白和甲状腺球蛋白。所制备的缀合物通过其分子量、T4与载体蛋白的摩尔比以及与抗Tr抗体结合的亲和力进行表征。血清T4结合蛋白与T4-缀合物的结合潜力值通过含有125I标记的缀合示踪剂、浓度远高于示踪剂的抗T4抗体以及浓度递增的T4结合蛋白的检测系统进行测定，并对结果进行适当的数学解释。我们得出结论，缀合物的分子量是一个显著影响缀合物与T4结合蛋白结合的参数。此外，对于分子量非常高（>650,000）的缀合物，在最终孵育混合物中使用20倍样品稀释时获得了零C值。
