Disease relevance of Potaba

• Two Salmonella typhi mutants, 541Ty (Vi+) and 543Ty (Vi-), auxotrophic for p-aminobenzoate and adenine, were evaluated as live oral vaccines [1].
• p-Aminobenzoate synthesis in Escherichia coli: purification and characterization of PabB as aminodeoxychorismate synthase and enzyme X as aminodeoxychorismate lyase [2].
• We report here the primary DNA and deduced amino acid sequences of the p-aminobenzoate synthase glutamine amidotransferase subunits from Salmonella typhimurium, Klebsiella aerogenes and Serratia marcescens [3].
• In Bacillus subtilis the trpX locus specifies a glutamine-binding protein designated subunit X, which forms a complex with subunit E to constitute the anthranilate synthase enzyme aggregate (EX) and subunit A to constitute the p-aminobenzoate synthase enzyme aggregate (AX) [4].
• The sequences of the anthranilate synthase genes in the fluorescent pseudomonads resemble those of p-aminobenzoate synthase genes of the enteric bacteria more closely than the anthranilate synthase genes of those organisms; however, no requirement for p-aminobenzoate was found in the Pseudomonas mutants created in this study [5].

High impact information on Potaba

• Folate synthesis in plants: the p-aminobenzoate branch is initiated by a bifunctional PabA-PabB protein that is targeted to plastids [6].
• p-Aminobenzoate biosynthesis in Escherichia coli. Purification of aminodeoxychorismate lyase and cloning of pabC [7].
• Historically the gene products of pabA and pabB were assumed to be sufficient for de novo p-aminobenzoate biosynthesis [7].
• A monoclonal antibody recognizing the FAD-binding site of 4-aminobenzoate hydroxylase from Agaricus bisporus [8].
• A monoclonal antibody against 4-aminobenzoate hydroxylase (EC 1.14.13.27) from Agaricus bisporus, a common edible mushroom, has been produced by the fusion of BALB/c mouse spleen cells immunized with the denatured enzyme and P3x63Ag8U1 myeloma cells in order to locate and characterize the catalytic site of the enzyme [8].

Chemical compound and disease context of Potaba

• Comparison of the amino acid sequences of the small subunits of yeast and E. coli carbamyl phosphate synthetases to the sequences of Component II of anthranilate and p-aminobenzoate synthases suggests that these amidotransferases are evolutionarily related [9].
• Escherichia coli p-aminobenzoate synthase is composed of two nonidentical subunits encoded by pabA and pabB and has been assumed to be the sole enzyme responsible for p-aminobenzoate biosynthesis from chorismate and glutamine [10].
• An Escherichia coli strain deficient in p-aminobenzoate synthesis was mutagenized, and derivatives were selected for growth on folic acid [11].
• Of the satellite fractions of Escherichia coli B dihydrofolate synthetases, a non-enzymic protein that is specifically able to bind p-aminobenzoate and sulphonamides has been purified 6000-fold by p-aminobenzoylcellulose affinity chromatography [12].
• Continuous degradation of mixtures of 4-nitrobenzoate and 4-aminobenzoate by immobilized cells of Burkholderia cepacia strain PB4 [13].

Biological context of Potaba

• Plasmids were constructed that overproduce the p-aminobenzoate synthase subunits 250-500-fold [10].
• Binding of substrate analogues bearing a 4-amino group (4-aminobenzoate and 2-hydroxy-4-aminobenzoate) leads to binding of a water molecule next to the active site Tyr385 [14].
• In addition, the phosphonamide peptide inhibited the hydrolysis of benzoyl (Bz)-Gly-Ala-Ala-Phe-(pAB) p-aminobenzoate and neurotensin by endopeptidase 24.15 with about a 10-fold lower potency (KI values of 5 and 7.5 nM respectively) [15].
• Nucleotide sequence of Escherichia coli pabB indicates a common evolutionary origin of p-aminobenzoate synthetase and anthranilate synthetase [16].
• J-Hydroxybenzoate: polyprenyl transferase and the prenylation of 4-aminobenzoate in mammalian tissues [17].

Anatomical context of Potaba

• Incubation of liver cytosol from mutant A and B6.A mice at 37 degrees C for 6 hr resulted in virtual cessation of p-aminobenzoate N-acetylation activity, whereas the steady-state level of immunoreactive NAT2 remained unchanged [18].
• Culturing HL-60 cells in the presence of p-aminobenzoate, a competitive inhibitor of polyprenyl-4-hydroxybenzoate transferase (Coq2p), produced a significant decrease of CoQ(10) levels without affecting cell viability [19].

Associations of Potaba with other chemical compounds

• In some micro-organisms, p-aminobenzoate synthase and anthranilate synthase share a common glutamine amidotransferase subunit [3].
• For p-aminobenzoate, its three most intense Raman features, due to a phenyl mode (1607 cm-1) and carboxylate stretching (1383 cm-1) and scissoring (863 cm-1) motions, are little perturbed upon binding and show no changes in the pH range 6.5-8 [20].
• The strategy included releasing the oligosaccharides by digestion of the purified glycoprotein with endoglycosidase H, separating the released oligosaccharides by high resolution gel filtration, and derivatizing the resulting reducing termini with the uv-absorbing moiety, ethyl p-aminobenzoate [21].
• Homology of pyridoxal-5'-phosphate-dependent aminotransferases with the cobC (cobalamin synthesis), nifS (nitrogen fixation), pabC (p-aminobenzoate synthesis) and malY (abolishing endogenous induction of the maltose system) gene products [22].
• Equilibrium solubilities of the first four homologous alkyl p-aminobenzoate esters were determined in methanol, ethanol, and 1-propanol at 25, 33, and 40 degrees; the esters and the alcohols comprise separate homologous series [23].

Gene context of Potaba

• The gene downstream from fic was found to be pabA (p-aminobenzoate) [24].
• Anthranilate synthetase is composed of proteins encoded by the genes trp(G)D and trpE, whereas p-aminobenzoate synthetase is composed of proteins encoded by pabA and pabB [16].
• Human serum biotinidase showed maximum activity in the pH range 6.0 to 7.5 with N-(d-biotinyl) p-aminobenzoate as substrate [25].
• The synthesis of a series of new C2-methyl-N10-alkylquinazoline-based thymidylate synthase (TS) inhibitors containing difluroinated p-aminobenzoate rings is described [26].
• This series was extensively studied by incorporating further substituents at N9 and C10 as well as by modifications to the p-aminobenzoate ring [27].

Analytical, diagnostic and therapeutic context of Potaba

• Purification of Escherichia coli B-specific p-aminobenzoate "pick-up" protein to homogeneity by affinity chromatography [12].
• Following centrifugation, 100 microliter of supernatant is mixed with 25 microliters of internal standard (25 micrograms/ml, ethyl p-aminobenzoate), and 50 microliters of this mixture is injected into the HPLC [28].
• Following enzymatic hydrolysis, the mixtures of substrates and products were derivatized with ethyl 4-aminobenzoate and separated by high-performance capillary electrophoresis in a borate buffer system using uv detection [29].
• The enzyme concentration dependence of spectrophotometric titrations of hog kidney D-amino acid oxidase [EC 1.4.3.3] with p-aminobenzoate was studied [30].
• Sulfa drug screening in yeast: fifteen sulfa drugs compete with p-aminobenzoate in Saccharomyces cerevisiae [31].

References