Solubilization of bacterial membrane proteins using alkyl glucosides and dioctanoyl phosphatidylcholine

The non-ionic detergent octyl glucoside solubilizes a substantial amount of Streptococcus faecalis membrane protein without loss of the monitored enzyme activities. A secondary detergent, dioctanoyl phosphatidylcholine, appears to increase the yield of solubilized material. In addition, the effect of ionic strength indicates that it may be possible to selectively extract groups of membrane proteins by their characteristic solubility at different ionic strengths.The solubilized membrane-associated enzymes, ATPase and NADH dehydrogenase enter polyacrylamide gels as distinct species. Electrophoretic studies suggest that there are two membrane-associated ATPases in the Streptococcus faecalis, one which dissociates from the membrane in the absence of Mg²⁺ ions and the other which remains particulate until solubilized by detergents.Octyl glucoside can be easily removed from a solution containing solubilized proteins and lipid by dialysis.