title: Labelling of the thyroid cell surface with 125I.
abstract: The surface membrane proteins of cultured porcine thyroid cells have been labelled with 125I by the lactoperoxidase method. Evidence that the labelling was restricted to the cell surface was supported by the high viability of the cells in suspension, the high proportion of labelled material in the particulate fraction after homogenization and electron-microscopic autoradiographic studies. The labelled proteins were analysed by electrophoresis on polyacrylamide gels containing sodium dodecyl sulphate and this indicated the presence of ten major labelled protein bands with approximate molecular weights of 175 000, 155 000, 135 000, 88 000, 80 000, 52 300, 39 000, 30 000, 21 000 and 14 300. Comparison of the electrophoretic patterns obtained with cultured human and porcine thyroid cells suggested that there were species differences in the proportions of lower-molecular-weight proteins.
mesh_terms: D000818:Animals; D001345:Autoradiography; D006801:Humans; D007457:Iodine Radioisotopes; D007784:Lactoperoxidase; D008565:Membrane Proteins / Q000032:analysis*; D013552:Swine; D013961:Thyroid Gland / Q000032:analysis* / Q000166:cytology
chemical_list: D007457:Iodine Radioisotopes; D008565:Membrane Proteins; D007784:Lactoperoxidase