A set of surface proteins common to the circulating human platelet and lymphocyte.

The surface proteins of the circulating human platelet and lymphocyte were labelled by using the lactoperoxidase iodination method. Polyacrylamide-gel electrophoresis showed that four corresponding labelled proteins are found on the surface of each cell type. The most intensely labelled protein contains little or no carbohydrate, but the remaining labelled proteins are all glycoproteins. The major labelled band from each cell was isolated and comparative peptide ;maps' showed that the two proteins are closely similar. The surface proteins of the lymphocyte and platelet are distinct from those on the erythrocyte, the remaining major type of circulating cell.