[2 phosphotransferase systems that control the second stage of phosphoenolpyruvate-dependent glucose phosphorylation in E. coli].
Analysis of E. coli W mutants defective in glucose transport suggests an existence of two enzyme systems which carry out the second step of phosphoenolpyruvate (PEP)-dependent glucose phosphorylation, thus controlling the glucose transport into E. coli cells. One system (PTS-glu-alpha) controls phosphorylation and transport of both glucose and alpha-methylglucoside, the other system (PTS-glu-beta) controls phosphorylation and transport of glucose only. PTS-glu-alpha system is damaged in the mutants studied, but PTS-glu-beta system is intact. On account of this fact the mutants do not uptake 14-C-alpha-methylglucoside and their extracts are practically incapable of its phosphorylation, phosphoenolpyruvate being used as phosphate donor. At the same time the mutants are capable of 14-C-glucose uptake and PEP-dependent 14-C-glucose phosphorylation. In one of the strain, having the intact PTS-glu-alpha system, the uptake of glucose and alpha-methylglucoside was stimulated by the addiction of glucose in the cultural medium. No such effect was observed in bacteria with the disturbed PTS-glu-alpha system and the intact PTS-glu-beta system. Probably, the PTS-glu-alpha system can be inducible, in contrast with the PTS-glu-beta system. The damage of the PTS-glu-alpha system results in resistance of bacteria to glucose-induced inhibition of the enzyme synthesis.
D001692:Biological Transport; D002250:Carbon Radioisotopes; D003470:Culture Media; D004794:Enzyme Repression / Q000187:drug effects; D004926:Escherichia coli / Q000201:enzymology / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism* / Q000494:pharmacology; D008757:Methylglucosides / Q000378:metabolism; D009154:Mutation; D010085:Oxidative Phosphorylation; D010728:Phosphoenolpyruvate / Q000494:pharmacology*; D010770:Phosphotransferases / Q000378:metabolism*
D002250:Carbon Radioisotopes; D003470:Culture Media; D008757:Methylglucosides; D010728:Phosphoenolpyruvate; D010770:Phosphotransferases; D005947:Glucose
Dve fosfotransferaznye sistemy, kontroliruiushchie vtoroĭ étap fosfoenolpiruvatzavisimogo fosforilirovaniia gliukozy u E. coli