The binding of detergents to lipophilic and hydrophilic proteins.

The lipophilic protein moieties of human low density lipoprotein, Semliii Forest virus envelope, and human erythrocyte stroma were obtained lipid-free with the use of sodium deoxycholate treatment and gel filtration in deoxycholatecontaining 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.