Evidence for vectorial phosphorylation of D-fructose by intact cells of Aerobacter aerogenes

Extracellular d-fructose was metabolized preferentially over intracellular d-fructose in growing cells of a d-fructokinaseless mutant of Aerobacter aerogenes. This finding is interpreted to indicate that phosphorylation of d-fructose by the membrane-bound phosphoenolpyruvate: d-fructose 1-phosphotransferase system in intact cells is coupled to unidirectional transport.