The binding of sodium dodecyl sulphate to various proteins.

1. The binding of sodium dodecyl sulphate to proteins by equilibrium dialysis was investigated. 2. Most of the proteins studied bound 90-100% of their weight of sodium dodecyl sulphate. 3. The glycoproteins studied bound 70-100% of their weight of sodium dodecyl sulphate, calculated in terms of the polypeptide moiety of the molecule. 4. Proteins not containing S.S groups bound about 140% of their weight of sodium dodecyl sulphate. 5. Reduction of four proteins containing S.S groups caused a rise in sodium dodecyl sulphate binding to 140% of the weight of protein. 6. The apparent micellar molecular weights of the protein-sodium dodecyl sulphate complexes were measured by the dye-solubilization method; they were all found to have approximately the same micellar molecular weight (34000-41000) irrespective of the molecular weight of the protein to which they were attached.