Boinding of S35-Labeled Sulfate in Serum of Rats as Studied by Filter-Paper Electrophoresis.∗

The binding of S35-labeled sulfate in rat serum has been investigated by filter paper electrophoresis. About 40% of the whole serum S35-sulfate activity was found to be combined with a serum constituent having the electrophoretic mobility of an α1-globulin. Although the chemical identity of the labeled substance has not yet been established, the results of these experiments suggest that it may be a protein with a sulfonated carbohydrate prosthetic group.