Chemical analyses of membranes isolated from Streptococcus mutans BHT

Cell membranes of Streptococcus mutans BHT (serotype b) were prepared following glass-bead disruption or mutanolysin digestion of whole cells. Major constituents of purified BHT membranes included: protein (60-65%), fatty acids (10%), glucose (3%), and phosphorus (0.5%). The principal amino acids measured were glutamate, aspartate, lysine, alanine, and leucine. The principal fatty acids measured were octadecenoic, palmitoleic, palmitic, and eicosenoic acids; smaller amounts of eicosanoic acid were also detected. Chemical analyses of membranes from cells grown to four different growth phases revealed no major shifts in composition during batch growth under our experimental conditions. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of these four membrane preparations confirmed the apparent compositional stability of cell membranes during growth.