Phosphoenolpyruvate-dependent glucose phosphotransferase activity in Streptococcus mitis ATCC 903.

A constitutive phosphoenolpyruvate (PEP)-dependent glucose phosphotransferase system was found in decryptified cells of Strep. mitis. The system displayed saturation kinetics and the apparent Km value for the non-fermentable analogue 2-deoxyglucose (2DG) was 0.4 mM. Sodium fluoride inhibited the activity when 2-phosphoglycerate was used as the energy source instead of PEP. Intact cells accumulated 2DG and also a derivative that behaved chromatographically like 2DG-6-phosphate. PEP-dependent glucose phosphotransferase activity was also demonstrated in freshly collected plaque.