The plant pathogenic Pseudomonas syringae pv. phaseolicola possesses a fructokinase which is epigenetically regulated. The KM values for fructose and ATP are 0.56 and 0.53 niM, respectively. About 23% of the activity observed with ATP was obtained with equimolar amounts of ITP. CTP, GTP, UTP, PEP and acetyl-P were ineffective. Fructokinase is responsible for the conversion of fructose to fructose-6-phosphate. In this way, fructose, which is formed intracellulary during the growth in a sucrose or mannose containing medium, can be metabolized via fructose-6-phosphate.