Diffusive gradients in the PTS system

It has recently been conjectured that metabolic pathways with membrane-bound enzymes can give rise to concentration gradients in the cytosolic pathway components. We investigate this issue using a theoretical model for the Phosphoenolpyruvate-dependent Phosphotransferase system in {it E. coli/, for which accurate measurements of the kinetic parameters are available. We show that significant spatial gradients indeed exist, and we discuss the potential implications of this finding.