Burton R M, Higgins P J, McConnell K P
Biochim Biophys Acta. 1977 Aug 23;493(2):323-31. doi: 10.1016/0005-2795(77)90188-x.
Radioactive selenite reacts with purified human and goat immunoglobulins at acidic and neutral pH. The antigenic properties of the immunoglobulins are retained during the selenium labelling as shown by immunoelectrophoresis and autoradiography. Pepsin digests of 75Se-labelled IgG possess 75Se both in the (Fab')2 fraction and in the low molecular weight peptides derived from the Fc domains. Alpha-1-acid glycoprotein, ribonuclease, and lysozyme are also labelled by this procedure. Enhancement of 75Se incorporation by urea, guanidinium chloride, mercaptoethanol, sodium sulfite and carrier selenite is interpreted as an effect of destabilization of IgG disulfide bonds. Up to 1.4 g atoms Se per mol IgG have been incorporated. We assume that selenite is cleaving disulfides by a process akin to sulfitolysis. The lability of the isolated 75Se-labelled IgG to high concentrations of mercaptans and sulfite is consistent with this idea. These 75Se-labelled proteins may be useful in structure studies and radioimmunoassay.
放射性亚硒酸盐在酸性和中性pH条件下与纯化的人及山羊免疫球蛋白发生反应。如免疫电泳和放射自显影所示，免疫球蛋白的抗原特性在硒标记过程中得以保留。经胃蛋白酶消化的75Se标记的IgG，其（Fab'）2片段和源自Fc结构域的低分子量肽中均含有75Se。α-1-酸性糖蛋白、核糖核酸酶和溶菌酶也可用此方法进行标记。尿素、氯化胍、巯基乙醇、亚硫酸钠和载体亚硒酸盐对75Se掺入的增强作用被解释为对IgG二硫键的去稳定化作用。每摩尔IgG已掺入高达1.4克原子的硒。我们假设亚硒酸盐通过类似于亚硫酸解的过程裂解二硫键。分离得到的75Se标记的IgG对高浓度硫醇和亚硫酸盐的不稳定性与这一观点相符。这些75Se标记的蛋白质可能在结构研究和放射免疫分析中有用。
