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Toshitada Noguchi - One of the best experts on this subject based on the ideXlab platform.
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Polyphosphate:AMP Phosphotransferase and polyphosphate:ADP Phosphotransferase activities of Pseudomonas aeruginosa.
Biochemical and biophysical research communications, 2001Co-Authors: Kazuya Ishige, Toshitada NoguchiAbstract:In Pseudomonas aeruginosa PAO1, we have found massive polyphosphate:AMP Phosphotransferase activity and polyphosphate:ADP Phosphotransferase activity known as the reverse catalytic activity of polyphosphate kinase which participates in polyphosphate synthesis in the bacterium. Biochemical analysis using the partially purified polyphosphate:ADP Phosphotransferase has revealed that it is independent of polyphosphate kinase and can function as polyphosphate-dependent nucleoside diphosphate kinase which most prefers GDP to the other three nucleoside diphosphates as a phospho-acceptor. It has been also demonstrated that polyphosphate:AMP Phosphotransferase activity marked in the bacterium mainly originates from the combined action of the polyphosphate:ADP Phosphotransferase described above and adenylate kinase. Both of the polyphosphate-utilizing activities require short polyP as a phospho-donor whose chain length is
Charles A. Brearley - One of the best experts on this subject based on the ideXlab platform.
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A Solanum tuberosum inositol phosphate kinase (StITPK1) displaying inositol phosphate-inositol phosphate and inositol phosphate-ADP Phosphotransferase activities
FEBS Letters, 2008Co-Authors: Samuel E. K. Caddick, Christopher J. Harrison, Ioanna Stavridou, Andrew M. Hemmings, Jennifer Mitchell, Charles A. BrearleyAbstract:We describe a multifunctional inositol polyphosphate kinase/Phosphotransferase from Solanum tuberosum, StITPKa (GenBank accession number: EF362784), hereafter called StITPK1. StITPK1 displays inositol 3,4,5,6-tetrakisphosphate 1-kinase activity: Km = 27 µM, and Vmax = 19 nmol min-1 mg-1. The enzyme displays inositol 1,3,4,5,6-pentakisphosphate 1-phosphatase activity in the absence of a nucleotide acceptor and inositol 1,3,4,5,6-pentakisphosphate–ADP Phosphotransferase activity in the presence of physiological concentrations of ADP. Additionally, StITPK1 shows inositol phosphate-inositol phosphate Phosphotransferase activity. Homology modelling provides a structural rationale of the catalytic abilities of StITPK1. Inter-substrate transfer of phosphate groups between inositol phosphates is an evolutionarily conserved function of enzymes of this class.
Kazuya Ishige - One of the best experts on this subject based on the ideXlab platform.
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Polyphosphate:AMP Phosphotransferase and polyphosphate:ADP Phosphotransferase activities of Pseudomonas aeruginosa.
Biochemical and biophysical research communications, 2001Co-Authors: Kazuya Ishige, Toshitada NoguchiAbstract:In Pseudomonas aeruginosa PAO1, we have found massive polyphosphate:AMP Phosphotransferase activity and polyphosphate:ADP Phosphotransferase activity known as the reverse catalytic activity of polyphosphate kinase which participates in polyphosphate synthesis in the bacterium. Biochemical analysis using the partially purified polyphosphate:ADP Phosphotransferase has revealed that it is independent of polyphosphate kinase and can function as polyphosphate-dependent nucleoside diphosphate kinase which most prefers GDP to the other three nucleoside diphosphates as a phospho-acceptor. It has been also demonstrated that polyphosphate:AMP Phosphotransferase activity marked in the bacterium mainly originates from the combined action of the polyphosphate:ADP Phosphotransferase described above and adenylate kinase. Both of the polyphosphate-utilizing activities require short polyP as a phospho-donor whose chain length is
Pieter W. Postma - One of the best experts on this subject based on the ideXlab platform.
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Limits to inducer exclusion: inhibition of the bacterial Phosphotransferase system by glycerol kinase
Molecular microbiology, 1998Co-Authors: Johann M. Rohwer, Rechien Bader, Hans V. Westerhoff, Pieter W. PostmaAbstract:The uptake of methyl α-D-glucopyranoside by the phosphoenolpyruvate-dependent Phosphotransferase system of Salmonella typhimurium could be inhibited by prior incubation of the cells with glycerol. Inhibition was only observed for glycerol preincubation times longer than 45 s and required the preinduction of both the glucose and the glycerol-catabolizing systems. Larger extents of inhibition by glycerol correlated with higher intracellular levels of glycerol kinase when the glp regulon had been induced to different extents. Preincubation with lactate did not inhibit methyl α-D-glucopyranoside uptake significantly, although both lactate and glycerol were oxidized by the cells. The cellular free-energy state of the cells (intracellular [ATP]/[ADP] ratio) was virtually identical for lactate and glycerol preincubation, suggesting that the inhibition of Phosphotransferase-mediated uptake was not a metabolic effect. In vitro, Phosphotransferase activity was inhibited to a maximal extent of 32% upon titrating cell-free extracts with high concentrations of commercial glycerol kinase. The results show that uptake systems that have hitherto been regarded merely as targets of the Phosphotransferase system component IIAGlc also have the capacity themselves to retroinhibit the Phosphotransferase system flux, presumably by sequestration of the available IIAGlc, provided that these systems are induced to appropriate levels.
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Control of Glucose Metabolism by the Enzymes of the Glucose Phosphotransferase System in Salmonella typhimurium
European journal of biochemistry, 1995Co-Authors: J. Van Der Vlag, R. Van 't Hof, K. Van Dam, Pieter W. PostmaAbstract:The quantitative role of the phosphoenolpyruvate:glucose Phosphotransferase system (glucose Phosphotransferase system) in glucose uptake and metabolism, and Phosphotransferase-system-mediated regulation of glycerol uptake, was studied in vivo in Salmonella typhimurium. Expression plasmids were constructed which contained the genes encoding enzyme I (ptsI), HPr (ptsH), IIAGlc (crr), and IICBGlc (ptsG) of the glucose Phosphotransferase system behind inducible promoters. These plasmids allowed the controlled expression of each of the glucose Phosphotransferase system proteins from about 30 % to about 300% of its wild-type level. When enzyme I, HPr or IIAGlc were modulated between 30% and 300% of their wild-type value, hardly any effects on the growth rate on glucose, the glucose oxidation rate, the rate of methyl α-d-glucopyranoside (a glucose analog) uptake or the Phosphotransferase-system-mediated inhibition of glycerol uptake by methyl α-d-glucopyranoside were observed. Employing the method of metabolic control analysis, it was shown that the enzyme flux control coefficients of these Phosphotransferase system components on the different measured processes were close to zero. The enzyme flux control coefficient of IICBGlc on growth on glucose or glucose oxidation was also close to zero. In contrast, the enzyme flux control coefficient of IICBGlc on the flux through the glucose Phosphotransferase system (transport and phosphorylation) was 0.72. The experimentally determined enzyme flux control coefficients allowed us to calculate the flux control coefficients of the phosphoenolpyruvate/pyruvate and methyl α-d-glucopyranoside/methyl α-d-glucopyranoside 6-phosphate couples and the process control coefficients of the phosphotransfer reactions of the glucose Phosphotransferase system. We discuss the implications of these values and the possible control points in the glucose Phosphotransferase system.
Samuel E. K. Caddick - One of the best experts on this subject based on the ideXlab platform.
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A Solanum tuberosum inositol phosphate kinase (StITPK1) displaying inositol phosphate-inositol phosphate and inositol phosphate-ADP Phosphotransferase activities
FEBS Letters, 2008Co-Authors: Samuel E. K. Caddick, Christopher J. Harrison, Ioanna Stavridou, Andrew M. Hemmings, Jennifer Mitchell, Charles A. BrearleyAbstract:We describe a multifunctional inositol polyphosphate kinase/Phosphotransferase from Solanum tuberosum, StITPKa (GenBank accession number: EF362784), hereafter called StITPK1. StITPK1 displays inositol 3,4,5,6-tetrakisphosphate 1-kinase activity: Km = 27 µM, and Vmax = 19 nmol min-1 mg-1. The enzyme displays inositol 1,3,4,5,6-pentakisphosphate 1-phosphatase activity in the absence of a nucleotide acceptor and inositol 1,3,4,5,6-pentakisphosphate–ADP Phosphotransferase activity in the presence of physiological concentrations of ADP. Additionally, StITPK1 shows inositol phosphate-inositol phosphate Phosphotransferase activity. Homology modelling provides a structural rationale of the catalytic abilities of StITPK1. Inter-substrate transfer of phosphate groups between inositol phosphates is an evolutionarily conserved function of enzymes of this class.
