Phosphoenolpyruvate-dependent formation of D-fructose 1-phosphate by a four-component phosphotransferase system.

Fructose' is metabolized in Aerobacter aerogenes primarily through the pathway: fructose -fructose-1-P -. fructose-1,6-P. Previous evidence for this pathway was the detection of an inducible fructose-i-P kinase2, I and the demonstration that a mutant lacking frustose-6-P kinase grew well on fructose but not on glucose, whereas a mutant lacking fructose 1,6-diphosphatase grew on glucose but not on fructose.' How widespread the occurrence of this new pathway is has not yet been assessed; however, the pathway has recently been demonstrated in Escherichia coli4 and fructose-l-P kinase occurs in Bacteroides symbiosis.5 In the present communication, we report on the initial reaction in the fructose1-P pathway. We show that in A. aerogenes fructose is phosphorylated with PEP' specifically at carbon atom 1 by a phosphotransferase system of the type originally described by Kundig et al.6 for other sugars and which has subsequently been implicated in the transport of sugars into bacterial cells as well as in their phosphorylation.7-15