Phosphoenolpyruvate-dependent sugar phosphotransferase activity in Megasphaera elsdenii

Megasphaera elsdenii was found to possess an inducible phosphoenolpyruvate:sugar phosphotransferase system for glucose and fructose but not for other hexoses, hexosamines, or hexitols. The complexity of the Megasphaera phosphoenolpyruvate:sugar phosphotransferase system lies intermediate to systems found in photoautotrophic bacteria and enteric bacteria. Megasphaera elsdenii phosphotransferase proteins exhibited enzymatic cross-reactivity with those from Escherichia coli; however, differences were found in substrate specificities and the physical characteristics of the proteins from these organisms. Sugar uptake was reduced in M. elsdenii stationary-phase as compared with log-phase cells and this loss correlated with a reduction in enzyme II function.