Iodination of cell membranes: I. Optimal conditions for the iodination of exposed membrane components

Iodination of red blood cells under optimal conditions by the Phillips-Morrison method leads to the iodination of two surface proteins. Modification of these conditions leads to the labeling of additional membrane proteins; labeling of hemoglobin can also occur. These results lead to the conclusion that, depending on the conditions of iodination, proteins located at various depths of the membrane can be labeled. This information was used in establishing an assay for the optimal iodination conditions of HeLa cells. Such iodinated HeLa cells grow at the same rate as control HeLa cells; most of these iodinated surface proteins can be removed by subsequent treatment with pronase.