Pseudomonas aeruginosa acid phosphatase activation by divalent cations and inhibition by aluminium ion (original) (raw)
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Molecular and Cellular Biochemistry
In this work the action of the following compounds upon Ps. aeruginosa acid phosphatase has been studied: 1) alkylammonium compounds; 2) aminoalcohols and aminoacids with different substituents (-H,-CH2OH and-CH3) attached to the nitrogen atom; 3) alcohols analogous to some compounds of the above series, but without the amino group. It was found that the enzyme inhibition was more effective with N-trimethylated compounds than with the triethylated ones. The degree of inhibition depended on the number of methyl groups bound to the nitrogen atom. Taking into account the choline and betnine series the hydroxyl derivatives showed more affinity for the enzyme than the carboxylated ones. In each series the Ki values increased with the decrease of methyl groups bound to the nitrogen atom. The presence of a positively charged nitrogen atom in the molecule of the effector was essential. These results enable us to confirm that in the molecule of Ps. aeruginosa acid phosphatase there exists an anionic site with one subsite with affinity for methyl groups.
Pseudomonas aeruginosa acid phosphatase contains an anionic site with a trimethyl subsite
Molecular and Cellular Biochemistry, 1988
In this work the action of the following compounds upon Ps. aeruginosa acid phosphatase has been studied: 1) alkylammonium compounds; 2) aminoalcohols and aminoacids with different substituents (-H, -CH2OH and -CH3) attached to the nitrogen atom; 3) alcohols analogous to some compounds of the above series, but without the amino group.
Molecular and Cellular Biochemistry, 1990
Choline, betaine and N,N-dimethylglycine as the sole carbon and nitrogen source induced a periplasmic acid phosphatase activity in Pseudomonas aeruginosa. This enzyme produced the highest rates of hydrolysis in phosphorylcholine and phosphorylethanolamine among the various phosphoric esters tested. At saturating concentrations of Mg 2+, the K~ values were 0.2 and 0.7 mM for phosphorylcholine and phosphorylethanolamine respectively. At high concentrations both compounds were inhibitors of the enzyme activity. The K~ ~ values for phosphorylcholine and phosphorylethanolamine were 1.0 and 3.0 mM respectively. The higher catalytic efficiency was that of phosphorylcholine. Considering these results it is possible to suggest that the Pseudomonas aeruginosa acid phosphatase is a phosphorylcholine phosphatase. The existence of this activity which is induced jointly with phospholipase C by different choline metabolites, in a high phosphate medium, suggests that the attack of Pseudomonas aeruginosa on the cell host may also be produced under conditions of high phosphate concentrations, when the alkaline phosphatase is absent.
Molecular and Cellular Biochemistry, 1984
Different compounds derived from choline, and obtained by demethylation or by oxidation of the primary alcohol group with subsequent N-demethylation, were tested as inducer agents of acid phosphatase and cholinesterase in Ps. aeruginosa. It was found that betaine and dimethylglycine were the most effective inducers of both enzyme activities. These metabolites including choline itself, were not inducers of acid phosphatase and cholinesterase in other Gram-negative bacteria such as: Escherichia coli, Salmonella typhimurium, Shigella flexneri, Enterobacter liquefacciens and Proteus mirabilis. The acid phosphatase activities found in these bacteria were not inhibited in vitro by choline, betaine and phosphorylcholine. From these results it may be concluded that the acid phosphatase activity from Ps. aeruginosa is different from the same activity observed in the other bacteria. In addition, it is also shown that Is. aeruginosa acid phosphatase and cholinesterase were inhibited by a number of compounds containing a positively charged amino group, with methyl or ethyl groups bound to it. These results seem to confirm that Ps. aeruginosa acid phosphatase and cholinesterase may contain a similar anionic site.
Phospholipase A activity in Pseudomonas aeruginosa
Zentralblatt für Bakteriologie : international journal of medical microbiology, 1995
Our study describes the production, purification and properties of an enzyme from Pseudomonas aeruginosa displaying the properties of phospholipase A. Maximal amounts of enzyme could be detected in the culture supernatant when the bacterium was grown for 3 to 5 days at 37 degrees C in stirred flask cultures containing brain heart infusion. The enzyme was purified by polyethylenimine precipitation and ammonium sulfate precipitation followed by gel filtration. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the enzyme preparation exhibited two bands with molecular weights of 13.5 and 60 kD, respectively. Correspondingly, two peaks of the same molecular weight could be demonstrated by high performance size exclusion chromatography. The activity toward the sn-2 ester binding of phospholipids was characterized and found to be highest towards phosphatidylcholine. Enzymatic activity was not influenced by the addition of calcium or EDTA while magnesium and strontium caused a d...
Phosphorylcholine Phosphatase: A Peculiar Enzyme of Pseudomonas aeruginosa
Enzyme research, 2011
Pseudomonas aeruginosa synthesizes phosphorylcholine phosphatase (PchP) when grown on choline, betaine, dimethylglycine or carnitine. In the presence of Mg(2+) or Zn(2+), PchP catalyzes the hydrolysis of p-nitrophenylphosphate (p-NPP) or phosphorylcholine (Pcho). The regulation of pchP gene expression is under the control of GbdR and NtrC; dimethylglycine is likely the metabolite directly involved in the induction of PchP. Therefore, the regulation of choline metabolism and consequently PchP synthesis may reflect an adaptive response of P. aeruginosa to environmental conditions. Bioinformatic and biochemistry studies shown that PchP contains two sites for alkylammonium compounds (AACs): one in the catalytic site near the metal ion-phosphoester pocket, and another in an inhibitory site responsible for the binding of the alkylammonium moiety. Both sites could be close to each other and interact through the residues (42)E, (43)E and (82)YYY(84). Zn(2+) is better activator than Mg(2+) a...
Current Microbiology, 1999
Pseudomonas aeruginosa phosphorylcholine phosphatase from periplasmic extracts of bacteria grown on choline as the sole carbon and nitrogen source was purified to homogeneity. The enzyme represented nearly 1% of the total protein found in the periplasmic space and is a monomer of approximately 53 kDa with an isoelectric point of 7.5. The optimum pH with phosphorylcholine was in the range of 5-8; with phosphorylethanolamine there was a peak at pH 6, and with p-nitrophenyl-phosphate (p-NPP) the optimum was at pH 5. Studies carried out at pH 5 indicated: i) For the three substrates above, Mg 2ϩ , Zn 2ϩ , or Cu 2ϩ was necessary for maximal activity. ii) With p-NPP, these cations bound to the free enzyme in an ordered bireactant system. iii) With phosphorylethanolamine, Mg 2ϩ , Zn 2ϩ , or Cu 2ϩ bound to the free enzyme in an at random bireactant system. iv) With phosphorylcholine, maximal activity was obtained with cation concentrations as low as 100 nM. v) Al 3ϩ ions were inhibitors of the enzyme activity. The n (Hill coefficient) values for the inhibition by Al 3ϩ with phosphorylcholine or p-NPP were 1 or 4, respectively. vi) The enzyme exhibited two affinity sites for phosphorylcholine. With Mg 2ϩ , a site with a K m value of 0.5 mM was detected; the corresponding V max was 25 µmol min Ϫ1 (mg protein) Ϫ1 ; without Mg 2ϩ , the enzyme displayed K m and V max values of 0.09 mM and 4.2 µmol min Ϫ1 (mg protein) Ϫ1 , respectively. Studies carried out at pH 7.4 indicated: i) The enzyme could not catalyze the hydrolysis of p-NPP, and phosphorylethanolamine was a poor substrate in either the presence or absence of divalent cations. ii) The enzyme activity measured with phosphorylcholine was independent of divalent cations or was not inhibited by Al 3ϩ ions. iii) With or without Mg 2ϩ , the enzyme exhibited two affinity sites for phosphorylcholine; the K m values were 0.05 mM and 0.5 mM with their corresponding V max of 5.6 and 25 µmol min Ϫ1 (mg protein) Ϫ1 , respectively.
Letters in Applied Microbiology
To evaluate the effect of tetradecyltrimethylammonium bromide (TTAB) and aluminium stresses on the phospholipid (PL) composition of Pseudomonas putida A ATCC 12633. Pseudomonas putida were grown with TTAB in the presence or absence of AlCl(3), and the PL composition was analysed. The presence of TTAB resulted in an increase in phosphatidylglycerol and phosphatidic acid levels (6- and 20-fold, respectively) with respect to the levels in cells grown without the surfactant. With AlCl(3), phosphatidylcholine (PC) increased (threefold) and cell-free extracts contained approximately threefold more phosphatidylcholine synthase activities than extracts without AlCl(3), indicating that the PC level is dependent upon activation of this enzyme. The negative charges of the headgroups of PL are the primary membrane-associated factors for the response to TTAB. PC are involved in cellular responses to binding Al(3+) and should be viewed as a temporary reservoir of available Al(3+) to allow a more ...