A novel phosphoprotein dependent on the bacterial phosphoenolpyruvate–sugar phosphotransferase system

1983 ◽  
Vol 61 (2-3) ◽  
pp. 150-153 ◽  
Author(s):  
E. Bruce Waygood ◽  
Roshan L. Mattoo
Keyword(s):  
Escherichia Coli ◽  
Salmonella Typhimurium ◽  
Growth Conditions ◽  
Phosphotransferase System ◽  
Crude Extracts ◽  
Enzyme I ◽  
Novel Protein

A protein has been found by isoelectricfocusing and autoradiography in Escherichia coli and Salmonella typhimurium which was phosphorylated by enzyme I and an histidine-containing phosphocarrier protein (HPr) of the phosphoenolpyruvate–sugar phosphotransferase system (PTS). This protein was not factor IIIglc nor was it specifically induced by fructose. Its presence in soluble crude extracts was dependent upon growth conditions; however, the two bacteria had different patterns and amounts in respect to this novel protein. The protein was present in S. typhimurium SB2950 which has an extensive deletion through the pts operon, thus indicating that it must be coded for elsewhere on the genome.

Determination of the levels of HPr and enzyme I of the phosphoenolpyruvate–sugar phosphotransferase system in Escherichia coli and Salmonella typhimurium

1983 ◽  
Vol 61 (1) ◽  
pp. 29-37 ◽  
Author(s):  
Roshan L. Mattoo ◽  
E. Bruce Waygood
Keyword(s):  
Escherichia Coli ◽  
Salmonella Typhimurium ◽  
Specific Activity ◽  
Phosphotransferase System ◽  
E Coli ◽  
Crude Extracts ◽  
Activity Measurements ◽  
A Cell ◽  
Enzyme I

The levels of histidine-containing protein HPr and enzyme I of the phosphoenolpyruvate–sugar phosphotransferase system of Escherichia coli strains 1100, NC3, W3110, and P650 and Salmonella typhimurium strains SB3507 and LJ144 have been determined by quantitative sugar phosphorylation assay and immunochemically. The levels have been determined for cells grown on minimal salts with glucose, fructose, mannitol, glycerol, and lactate and on nutrient broth. All determinations indicate a two- to three-fold change in the levels of enzyme I and HPr between growth on hexoses, which gave the higher levels, and the other growth substrates. The highest levels were not always found in glucose-grown cells. Antibodies were produced in rabbits using purified proteins from E. coli P650. The activity measurements and immunochemically determined enzyme I protein gave specific activities in the crude extracts of E. coli strains which were similar to that of the pure enzyme. The wild-type S. typhimurium enzyme I in crude extracts did not have the same immunochemical reactivity, although there was a considerable cross-reaction and the specific activity appeared to be half that of pure enzyme I. The HPr from both E. coli and S. typhimurium behaved identically and, although the immunoprecipitation was weak, it did indicate that HPr assays may not be as reliable as the enzyme I assays. The relative amounts of enzyme I and HPr found indicate that there are between 10- and 20-fold more HPr molecules in a cell than enzyme I subunits which form active dimers.

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