Pathway of fructose utilization by Escherichia coli

The utilization of fructose by Escherichia coli. Properties of a mutant defective in fructose 1-phosphate kinase activity

“…The fructose 1-phosphate kinase activity of ultrasonic extracts of E. coli was measured as described by Ferenci & Kornberg (1971a). The fructosephosphoenolpyruvate phosphotransferase activity of toluene-treated cell suspension was determined essentially by the method of Kornberg & Reeves (1972), except that 1.0mM-EDTA (disodium salt) was included in the buffer used for toluene treatment of the cells, and that the phosphoenolpyruvate concentration used in the assay was raised to 2.5mM.…”

“…The role of the fructose-phosphoenolpyruvate phosphotransferase in the uptake of, and growth on, fructose by E. coli has been demonstrated clearly through the isolation of mutants devoid of Enzyme I or HPr (for review, see Lin, 1970) or of the fructosespecific Enzyme II (Ferenci & Kornberg, 1971a). No such clear evidence exists on the fate of fructose 1-phosphate.…”

“…It is further known that in E. coli (Fraenkel, 1968b;Ferenci & Kornberg, 1971a), as in Aerobacter aerogenes (Hanson & Anderson, 1968) and Bacillus subtilis (Marquet et al, 1970), the phosphorylated product of reaction (2) is virtually only fructose 1-phosphate when a low concentration (<2mM) of fructose is present, though fructose 6-phosphate can also be formed at high fructose concentrations (Ferenci & Kornberg, 1971b): was first discovered in Bacteroides symbiosus (Reeves et al, 1966). It has also been demonstrated to be inducibly formed by E. coli after exposure of that organism to fructose (Fraenkel, 1968b) or fructose 1-phosphate (Ferenci & Kornberg, 1971a), but no mutants of E. coli devoid of this enzyme have yet been described. It is the purpose of the present paper to remedy this deficiency.…”

Isolation and properties of a regulatory mutant in the hexose phosphate transport system of Escherichia coli

“…The observation [6] that an E. coli mutant devoid of the ability to grow upon fructose can grow upon fructose-l -phosphate shows that this phosphorylated compound can enter E. coli without prior hydrolysis to fructose. However, this ability to utilize fructosel-phosphate is manifested only by cultures that have been exposed previously to substances that induce the uptake system for hexose-6-phosphates (UHP), and persists for only about I-11% doublings on fructose-l-phosphate (61 .…”

“…A mutant of the latter type, KL 16-l lc-21, was isolated from the Hfr strain KL 16-21: this strain is not capable of utilizing free fructose [6] ; selection of mutants of the latter type would thus be favoured. KL 16-11 c-2 1 was obtained by spreading cultures of KL 16-21 on minimal salts-agar plates containing 2 mM fructose-l -phosphate as carbon source: the colonies that appeared after 48-72 hr at 37" were picked and purified by single-colony isolation.…”