On the fidelity of the lactoperoxidase method of cell membrane radioiodination: an electron microscopic autoradiographic study.
The radiolabelling of human peripheral blood lymphocytes by lactoperoxidase-catalysed iodination using 2 different sources of hydrogen peroxide has been compared using electron microscopic autoradiography. A method of statistical analysis of the autoradiographs has permitted precise identification of radioactive sources, in particular cellular compartments, taking into account cross-fire of Auger electrons producing silver grains in compartments other than those from which they are emitted. Our data confirm the postulates of previous investigators that the majority of radioiodine is located at the plasma membrane of cells labelled by enzymic iodination. The results further suggest that the glucose-glucose oxidase system for generation of hydrogen peroxide permits a greater degree of specific radiolabelling of plasma membrane proteins with less damage than equivalent lactoperoxidase iodination reactions promoted by exogenously added hydrogen peroxide.
D001345:Autoradiography; D001402:B-Lymphocytes; D002460:Cell Line; D006801:Humans; D007457:Iodine Radioisotopes; D007784:Lactoperoxidase / Q000378:metabolism*; D008214:Lymphocytes / Q000166:cytology; D008223:Lymphoma; D008565:Membrane Proteins / Q000032:analysis*; D008854:Microscopy, Electron; D010544:Peroxidases / Q000378:metabolism*
D007457:Iodine Radioisotopes; D008565:Membrane Proteins; D007784:Lactoperoxidase; D010544:Peroxidases