Moutafchiev D, Sirakov L, Bontchev P
Department of Biochemistry, Medical Faculty, Medical University, Sofia, Bulgaria.
Biol Trace Elem Res. 1998 Feb;61(2):181-91. doi: 10.1007/BF02784029.
Using a homologous competition of 54Mn-transferrin with Mn-transferrin and 65Zn-transferrin with Zn-transferrin, it was found that on the plasma membrane of lactating mouse mammary gland cells there are receptor binding Mn-transferrin and Zn-transferrin. The heterologous competition between labeled and nonlabeled Fe-transferrin, Mn-transferrin and Zn-transferrin, as well as almost equal affinity constants of cellular receptors toward the three metals by competition of Fe-transferrin suggests that one and the same receptor accepts all three metals from the transferrin molecule. The cell receptors therefore possess a polymetal binding function. A model and a mechanism for regulation of the transport metal flow toward the mammary gland cell acting like "automated switching over" are proposed.
通过54Mn-转铁蛋白与锰-转铁蛋白以及65Zn-转铁蛋白与锌-转铁蛋白的同源竞争实验发现，泌乳小鼠乳腺细胞的质膜上存在结合锰-转铁蛋白和锌-转铁蛋白的受体。标记和未标记的铁-转铁蛋白、锰-转铁蛋白和锌-转铁蛋白之间的异源竞争，以及通过铁-转铁蛋白竞争表明细胞受体对这三种金属具有几乎相等的亲和常数，这表明同一个受体从转铁蛋白分子中接受所有三种金属。因此，细胞受体具有多金属结合功能。提出了一种调节金属向乳腺细胞运输流的模型和机制，其作用类似于“自动切换”。
