Lalloz M R, Byfield P G, Himsworth R L
Clin Endocrinol (Oxf). 1984 Oct;21(4):331-8. doi: 10.1111/j.1365-2265.1984.tb03219.x.
A euthyroid adult female (LC) was found to have persistently raised concentrations of total T4 (159 nmol/l) and rT3 (500 pmol/l) in her serum in association with a normal T3 (2.1 nmol/l). Serum concentrations of all three T4-binding proteins were within normal limits. A variant prealbumin with an increased affinity for T4 was found to be responsible for the raised serum level of T4. Unlike normal prealbumin, the variant also bound appreciable amounts of rT3. The affinity constant for T4 binding to prealbumin LC was 5.5 X 10(8) l/mole which is sevenfold higher than that obtained for normal prealbumin (8.5 X 10(7) l/mole). The affinity constant for the binding of rT3 to prealbumin LC was 2.0 X 10(6) l/mole while that for the normal protein was unmeasurable by our method. The T4-binding capacity of prealbumin LC in serum was within the normal range indicating that there is no new additional T4-binding site on the protein. Prealbumin LC has the same molecular size as the normal protein, hence it is likely that the tetrameric structure has been preserved. The electrophoretic mobility of prealbumin LC was normal indicating no alteration in charge. It is postulated that the increased affinity for T4 (and presumably for rT3) results from a hydrophobic amino-acid substitution in the prealbumin monomer.
一名甲状腺功能正常的成年女性（LC）血清中总T4（159 nmol/l）和反T3（500 pmol/l）浓度持续升高，而T3（2.1 nmol/l）正常。所有三种T4结合蛋白的血清浓度均在正常范围内。发现一种对T4亲和力增加的前清蛋白变异体导致了血清T4水平升高。与正常前清蛋白不同，该变异体还结合了相当数量的反T3。T4与前清蛋白LC结合的亲和常数为5.5×10⁸ l/摩尔，比正常前清蛋白（8.5×10⁷ l/摩尔）高7倍。反T3与前清蛋白LC结合的亲和常数为2.0×10⁶ l/摩尔，而正常蛋白的亲和常数用我们的方法无法测量。血清中前清蛋白LC的T4结合能力在正常范围内，表明该蛋白上没有新的额外T4结合位点。前清蛋白LC与正常蛋白具有相同的分子大小，因此很可能保留了四聚体结构。前清蛋白LC的电泳迁移率正常，表明电荷没有改变。据推测，对T4（可能对反T
