polyacrylamide gel electrophoresis of the phosphorylated membrane proteins followed by scintillation counting of gel slices and autoradiography showed that the polypeptides of molecular weights 28000 , 23000 and 19000 were phosphorylated , and 32p from [ gamma-32p ] atp having been incorporated into serine residues of the substrate proteins .
C0025252
membrane proteins
C0033684
proteins