d-MANNITOL 1-PHOSPHATE DEHYDROGENASE FROM ESCHERICHIA COLI

Mutants of Escherichia coli K-12 defective in the mannitol-specific enzyme II complex of the phosphoenolpyruvate phosphotransferase system (PTS) or lacking mannitol-1-phosphate dehydrogenase have been isolated. These mutants fail only to grow on mannitol. Growth of the dehydrogenase-negative mutant on casein hydrolysate can be abruptly inhibited by exposure to mannitol. A mutant with constitutive expression of both of these enzymes has also been isolated. All three mutations are clustered in a region represented at min 71 of the Taylor map. In a mutant with less than 5% of the activity of enzyme I of the PTS, both the enzyme II complex and the dehydrogenase remain inducible by mannitol. In the mutant defective in the enzyme II complex, mannitol is able to induce the dehydrogenase. Thus, mannitol, rather than its phosphorylated product, seems to be the inducer.

mentioning

confidence: 99%

Mutations Affecting the Dissimilation of Mannitol by Escherichia coli K-12

Solomon

Lin

1972

“…cation was taken to the passage through QAE-Sephadex A15 (10). Mannitol-1-phosphate dehydrogenase was assayed by the method of Wolff and Kaplan (29).…”

Section: Methodsmentioning

confidence: 99%

“…D-Mannitol, the most ubiquitous natural hexitol, can serve as a carbon source for Escherichia coli, entering the cells through a specific phosphotransferase transport system (PTS) (27). The resultant mannitol-1-phosphate is oxidized by a specific dehydrogenase (29) in the presence of NAD to fructose-6-phosphate, which enters the general metabolic pathways. The PTS enzyme II and the dehydrogenase are controlled by the genes mtlA and mtlD, respectively.…”

mentioning

confidence: 99%

Rapid turnover of mannitol-1-phosphate in Escherichia coli

Rosenberg¹,

Pearce²,

Hardy³

et al. 1984

The phosphate moiety of D-mannitol-1-phosphate in Escherichia coli is subject to rapid turnover and is in close equilibrium with Pi and the phosphorus of fructose-1,6-bisphosphate. These three compounds account for the bulk of 32P label found in cells after several minutes of uptake of 32Pi and mannitol-1-phosphate represents some 30% of this label. Mannitol-1-phosphate occurs in E. coli grown on a variety of carbon sources, in the absence of D-mannitol, and is synthesized de novo even in mutants lacking mannitol-1-phosphate dehydrogenase. The mannitol moiety of mannitol-1-phosphate was not affected during the total chase of the P moiety, which exchanged with a half-life of about 30 s. These findings suggest that the rapid equilibration of the phosphorus is a function of an enzyme, possibly a component of the phosphotransferase system, capable of forming a complex that allows the exchange of the phosphate without the equilibration of the mannitol moiety with free mannitol.

“…mutans, which contains a Mtl-l-P dehydrogenase (7), produces extracellular Mtl after resting-cell suspensions metabolize glucose anaerobically (23). E. coli also contains a Mtl-l-P dehydrogenase (38,39) and accumulates Mtl-1-P during glucose metabolisn. It was not completely unexpected, then, that Mtl accumulated in some strains of E. coli and in S. mutans.…”

Section: Bs and 6834mentioning

confidence: 99%

Intracellular mannitol, a product of glucose metabolism in staphylococci

Edwards¹,

Blumenthal²,

Khan³

et al. 1981

Mannitol (Mtl), not previously reported as an intracellular component of bacteria, although it has been found as an extracellular end product of anaerobic carbohydrate metabolism, accumulated within strains of all 10 staphylococcal species tested after aerobic incubation of washed cell suspensions in phosphate-buffered 1% glucose for 2 h. Phenol extracts of the cells, before and after incubation, were analyzed for Mtl content by periodate utilization and paper chromatography and for Mtl 1-phosphate content, with Mtl 1-phosphate dehydrogenase. In Staphylococcus aureus Towler, the content of Mtl increased from a 0-h value of less than 2.4 to 16 mumol/g (dry weight) after incubation, and the level of Mtl 1-phosphate increased from a 0-h value of 1 to 8 mumol/g. The identification of Mtl was confirmed as the per-O-acetyl ester by gas-liquid chromatography and as the per-O-methyl ether by mass spectrometry. Also tested were 5 additional S. aureus strains and 32 coagulase-negative staphylococcal strains. All strains accumulated Mtl, even those strains that could not utilize exogenous Mtl during aerobic growth, usually in the range 4 to 25 mumol/g. Furthermore, three strains accumulated very high Mtl levels. Bacteria from several other genera were tested, and some were found to accumulate low to moderate levels of Mtl under similar incubation conditions. The metabolic conversion of glucose to intracellular Mtl, probably via Mtl 1-phosphate, is a common feature of staphylococci and also occurs in some other bacteria.