The Binding of Detergents to Lipophilic and Hydrophilic Proteins

Abstract The lipophilic protein moieties of human low density lipoprotein, Semliki Forest virus envelope, and human erythrocyte stroma were obtained lipid-free with the use of sodium deoxycholate treatment and gel filtration in deoxycholate-containing media. Detergent binding was determined by subjecting the proteins to gel filtration in the presence of micellar concentrations of radioactive deoxycholate or the nonionic detergent Triton X-100. The amount of detergents bound to the proteins could be measured from the amount of radioactive detergent that co-eluted with the protein. The lipophilic proteins bound large amounts of deoxycholate and Triton X-100 (up to about 70% of their weight). The hydrophilic proteins tested bound little or no deoxycholate or Triton X-100.