Glucose transport in Streptococcus mutans: preparation of cytoplasmic membranes and characteristics of phosphotransferase activity.

Cytoplasmic membranes from Streptococcus mutans were used to study phosphoenolpyruvate (PEP)-dependent glucose transport. The Km values for glucose and PEP were 0.3 and 0.4 mM. The system was sensitive to sulfhydryl reagents and detergents. The nonmetabolizable analogue 2-D-deoxyglucose was readily phosphorylated while alpha-methyl-glucose and 3-0-methylglucose were inefficiently derivatized. The fermentable sugars fructose, galactose, mannitol, and sorbitol were phosphorylated at reduced rates.