SEARCH · Search PubMed
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Anthranilate-5-phosphoribosylpyrophosphate phosphoribosyltransferase was purified from the bacterium Erwinia carotovora, a member of the Enterobacteriaceae. The enzyme was homogeneous according to the criteria of gel electrophoresis and NH2-terminal amino acid sequence analysis. The molecular weight of the enzyme as determined on a calibrated Sephadex G-200 column was 67,000 +/- 2,000. Sodium dodecyl sulfate-polyacrylamide gels gave a subunit molecular weight of 40,000 +/- 1,000, suggesting that the enzyme was a dimer. A comparison of the NH2-terminal sequence of the enzyme with the (previously determined) homologue from Serratia marcescens, a monomer with a molecular weight of 45,000, showed that the larger Serratia subunit came into register with amino acid 14 of the Erwinia subunit. The register for the length of the known overlap, 26 amino acids, was highly conserved.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The indole-3-glycerolphosphate synthase/anthranilate synthase complex from Saccharomyces cerevisiae was purified to apparent homogeneity. The native complex with Mr approximately equal to 130 000 consists of two different subunits, the TRP2 gene product with Mr = 64 000 and the TRP3 gene product with Mr = 58 000. The larger polypeptide was identified as anthranilate synthase and is active in vitro with ammonia as cosubstrate without need of complex formation. The smaller polypeptide carries both glutamine amidotransferase activity and indole-3-glycerolphosphate synthase activity. Various steady-state kinetic parameters as well as the amino acid composition of the two polypeptides were determined.
Explore the source record for details and available documents.
Kynurenine, 3-hydroxyanthranilic, anthranilic and nicotinic acids at concentrations 10(-4) and 10(-5) M potentiated contractions of the isolated rat rectum produced by acetylcholine. Contractile response of the phrenico-diaphragmatic preparation of young rats to acetylcholine was diminished by kynurenine, 3-hydroxykynurenine and by quinolinic acid. In rats of both sexes, 3-hydroxyanthranilic, anthranilic, picolinic and nicotinic acids in doses of 10 and 20 mg/kg shortened the latency of oxotremorine tremor. Quinolinic and nicotinic acids reduced the latency of nicotinic tremor and potentiated hypothermia.
1. An enzyme solely localized in the nuclear fraction of rat liver was found to convert 3-hydroxyanthranilic acid into a red product that was isolated and crystallized from the reaction mixture. The product was identified as cinnabarinic acid (2-amino-3-oxo-3H-phenoxazine-1,9-dicarboxylic acid) by comparing its properties with synthetic cinnabarinic acid. 2. The enzyme had optimum pH at 7.2. Heavy-metal ions like Ag(+), Hg(2+), MoO(4) (2-), Fe(2+) and Cu(2+) were inhibitory; Mn(2+) activated the reaction to a considerable extent. 3. The reaction was inhibited by mercaptoethanol, GSH and cysteine, and activated by p-hydroxymercuribenzoate and sodium arsenite, which may suggest the involvement of disulphide groups in the reaction.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Articular cartilage is a highly specialized smooth connective tissue whose proper functioning depends on the maintenance of an extracellular matrix consisting of an integrated assembly of collagens, glycoproteins, proteoglycans (PG), and glycosaminoglycans. Isomeric chondroitin sulfate glycoforms differing in position and degree of sulfation and uronic acid epimerization play specific and distinct functional roles during development and disease onset. This work introduces a novel glycosaminoglycan extraction method for the quantification of mixtures of chondroitin sulfate oligosaccharides from intact cartilage tissue for mass spectral analysis. Glycosaminoglycans were extracted from intact cartilage samples using a combination of ethanol precipitation and enzymatic release followed by reversed-phase and strong anion exchange solid-phase extraction steps. Extracted chondroitin sulfate glycosaminoglycans were partially depolymerized using chondroitinases, labeled with 2-anthranilic acid-d(4) (2-AA) and subjected to size exclusion chromatography with online electrospray ionization mass spectrometric detection in the negative ion mode. The method presented herein enabled simultaneous determination of sulfate position and uronic acid epimerization in juvenile bovine and adult human cartilage samples. The method was applied to a series of 13 adult human cartilage explants. Standard deviation of the mean for the measurements was 1.6 on average. Coefficients of variation were approximately 4% for all compositions of 40% or greater. These results show that the new method has sufficient accuracy to allow determination of topographical distribution of glycoforms in connective tissue.
Mutants with internal deletions that terminate near the operator end of the tryptophan operon of E. coli were used in studies on the nucleotide sequence at the 5' end of the messenger RNA transcribed on this operon. The findings obtained permitted identification of a sequence of 43 nucleotides corresponding to the aminoterminal 11 amino acids of anthranilate synthetase component I, the polypeptide specified by the operator-proximal structural gene of the operon. It was also shown that the translation initiation codon for this polypeptide is preceded on the messenger by a "leader" sequence of unknown function, at least 150 nucleotides in length.
Explore the source record for details and available documents.
Serratia marcescens anthranilate synthase Component I (AS I) was purified from a plasmid-containing Escherichia coli strain. Residues essential for AS I function were studied by chemical modification reactions. Phenylglyoxal and 1,2-cyclohexanedione modified 2-5 arginine residues and inactivated AS I. The substrate chorismate reduced the rate of inactivation. Analysis of inactivation data indicated that 1 arginine residue is essential for activity. Histidine residues in AS I were modified by ethoxyformic anhydride and by photooxidation. Enzyme inactivation accompanied modification of histidine residues. Inactivation was prevented by substrate. Comparison of the number of carbethoxy groups incorporated between substrate-protected and unprotected AS I indicated that 1 histidine residue is required for activity. AS I was also inactivated by bromopyruvate. Substrate retarded inactivation by bromopyruvate. A differential labeling experiment indicated that the loss of AS I activity was correlated with alkylation of 1 cysteine residue. A tryptic peptide containing the essential cysteine residue was isolated. The peptide has the amino acid sequence of Ile-Cys-Gln-Ala-Gly-Ser-Arg.
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). Subunit X confers upon these enzyme complexes the ability to utilize glutamine as a substrate. The trpX locus has been examined to determine its map position and control. (i) The trpX locus was found to be cotransformed with the lysS and pabA loci. The results of three-factor transformation analyses suggest the following order of these markers: lysS-sul-trpX-pabA. (ii) Mutation to constitutivity of the tryptophan operon resulted in a 50- to 60-fold increase in the level of subunit X when the mutant contained functional trE and abA gene products; however, in the absence of subunit E there was only a 4- to 5-fold increase in the glutamine-binding protein. (iii) Formation of subunit X was derepressed under conditions that allow for the derepression of the trpE and/or pabA loci. (iv) Subunit X synthesis was derepressed to a greater extent in mutants that contain a functional trpE gene product than in mutants that contain a nonsense mutation in the trpE locus. These results are consistent with the hypothesis that the trpE and pabA gene products affect the expression and control of the trpX locus.
Each of six kynurenines tested (DL-kynurenine, quinolinic, 3-hydroxy-anthranilic, xanthurenic, picolinic, and nicotinic acids) injected into brain ventricles in mice in doses of 25--60 mcg produced motor excitement and/or clonic convulsions. Anthranilic acid did not produce these effects. The strongest metabolite was quinolinic acid, which was active in a dose of 1 mcg. It was also the only compound which produced motor excitement and convulsions after intraperitoneal injection (in doses of 400--600 mg/kg, i.e. 10,000--15,000 mcg per mouse). The hypothermic effect of intraventricularly-injected kynurenines was roughly similar to that of intraperitoneally-injected material at 100--1000 times higher doses. These data suggest poor penetration of kynurenines formed in the liver into the brain, and the possible involvement of these metabolites of tryptophan (particularly if they are formed inside the brain) in the mechanism of seizures.