Fractionation and Partial Characterization of Proteins of the Bileaflet Nuclear Membrane from Rat Liver

The sodium dodecyl sulfate (SDS)-solubilized proteins of the bileaflet nuclear membrane from rat liver have been fractionated by gel Htration.More than 23 different molecular weight classes of proteins ranging from 160,000 to 16,000 can be distinguished by conventional SDS-polyacrylamide gel electrophoresis.Polypeptide chains of less than 16,000 were not detected.A triplet, the respective proteins of which have molecular weights of 64,000, 70,000, and 74,000, account for 25% of the total membrane protein, while a second group of proteins in the range of 53,000 to 60,000 represents an additional 21%.The amino acid composition of the individual fractions does not exhibit