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PubMedDate not supplied

[Participation of cyclic nucleotides in the mechanism of regulation of the tissue pool of coenzyme A and the acetylizing capacity of rats].

cAMP and dibutyryl-cAMP were shown to increase the pool of CoA (or all the pantothenic coenzymes) in rat liver tissue, especially after treatment of the animals with 4-phosphopantothenate but not with pantethine. As shown by experiment with inhibitors of protein synthesis (actinomycin D, actidion, chloramphenicol) immediate c-AMP-dependent stimulation of the biogenesis of pantothenic coenzymes occurred rather from their precursors than due to induction of enzymes, participating in the biogenesis, or to destruction of the pantothenic coenzymes. Experiments with chloramphenicol exhibited that cAMP regulation of the biogenesis of pantothenic coenzymes in mitochondria was responsible mainly for the cellular pool of CoA and, partly, for the acetylation of para-aminobenzoic acid in tissues.

4-Aminobenzoic Acid↗
PubMed1988

Simplified oral pancreatic function test.

The standard Bentiromide test and a new modified test using p-aminosalicylic acid (PAS) as a pharmacokinetic marker for p-aminobenzoic acid (PABA) have been evaluated in the detection of pancreatic exocrine insufficiency in children. The conventional two day test using a colorimetric assay for urinary PABA discriminated poorly between five children with pancreatic insufficiency and 13 others with normal pancreatic function. Two further groups of patients, comprising 28 with pancreatic exocrine insufficiency and 20 with normal pancreatic function underwent the modified test, and urine samples were analysed by high performance liquid chromatography. The results showed a complete separation between groups. The use of PAS eliminates a number of sources of error inherent in a two day Bentiromide test and provides a simplified and accurate diagnostic test for pancreatic insufficiency. The PABA-PAS modified test enables collection of the urine to be done during a single six hour period.

4-Aminobenzoic Acid↗
PubMed1964

THE GENUS VEILLONELLA . II. NUTRITIONAL STUDIES.

Rogosa, M. (National Institute of Dental Research, U.S. Public Health Service, Bethesda, Md.), and Ferial S. Bishop. The genus Veillonella. II. Nutritional studies. J. Bacteriol. 87:574-580. 1964.-A medium is described for the study of the vitamin, hypoxanthine, putrescine, or cadaverine requirements of 86 Veillonella isolates from man, rabbit, rat, and hamster. No organism required riboflavine or folic acid for growth. Niacin and calcium pantothenate were often stimulatory, but in nearly all cases were dispensable. Biotin and p-aminobenzoic acid were frequently stimulatory and sometimes indispensable for continued growth. V. parvula (antigenic group VI) required pyridoxal and thiamine and did not require putrescine or cadaverine. V. alcalescens (antigenic group IV) required pyridoxal, generally required thiamine, and also required putrescine or cadaverine. Of the isolates, 25 from the rat and 3 from the hamster (antigenic group II) generally behaved like V. parvula, except that a putrescine or cadaverine requirement was often observed. Spermine, spermidine, and agmatine could not replace putrescine or cadaverine. Although succinate is metabolized by resting cells, the organisms could not grow with succinate as an energy source.

4-Aminobenzoic Acid↗
PubMedDate not supplied

Inhibition of human red blood cell N-acetyltransferase.

Acetanilide and derivatives of benzoic acid, benzamide, salicylic acid, and salicylamide were tested as inhibitors of p-aminobenzoic acid N-acetyltransferase partially purified from peripheral blood of three rapid and two slow dapsone acetylator human volunteers. The 50% inhibition point of these compounds does not provide a kinetic basis for differentiating the rapid and slow dapsone acetylator phenotypes.

4-Aminobenzoic Acid↗
PubMed1983

Transport characteristics of p-acetamidobenzoic acid in brush border membrane of rat small intestine.

Brush border membrane vesicles of rat small intestinal mucosa were prepared by the modified calcium precipitation method in order to investigate the intestinal secretion mechanism of p-acetamidobenzoic acid (Ac-PABA). The release rate of [14C]-Ac-PABA from preloaded vesicles was much faster than that of p-aminobenzoic acid (PABA) and was enhanced by the addition of unlabelled Ac-PABA in the outer medium. In contrast, the membrane transfer rate of Ac-PABA across the egg lecithin liposomes was slower than that of PABA. The contribution of a carrier-mediated transport mechanism in the brush border membrane to the intestinal secretion of Ac-PABA was suggested.

4-Aminobenzoic Acid↗
PubMed1983

Inhibitory activity and mode of action of diaminodiphenylsulfone in cell-free folate-synthesizing systems prepared from Mycobacterium lufu and Mycobacterium leprae. A comparison.

Cell-free folate synthesizing extracts have been isolated from Escherichia coli, Mycobacterium lufu, Mycobacterium smegmatis (ATCC 607) and Mycobacterium leprae, and the inhibitory power of diaminodiphenylsulfone (DDS) in such cell-free systems on the synthesis of dihydropteroic acid has been determined. M. lufu and M. leprae extracts show very similar high sensitivities against DDS. Mode of action studies seem to indicate that the observed high sensitivity of M. lufu and M. leprae as compared to E. coli can be solely attributed to a high affinity for the dihydropteroic acid synthetase. A dihydropteroic acid analog formation where DDS is incorporated instead of p-aminobenzoic acid--as has been observed in E. coli--could not be detected.

4-Aminobenzoic Acid↗
PubMed1991

n-Alkyl p-aminobenzoates as derivatizing agents in the isolation, separation, and characterization of submicrogram quantities of oligosaccharides by liquid secondary ion mass spectrometry.

In this laboratory we are pursuing a comprehensive strategy for isolation and characterization of oligosaccharides from glycoproteins that are available only in limited quantities. To improve sensitivity in the analysis by liquid secondary ion mass spectrometry, we have investigated the relative behavior of a homologous series of n-alkyl esters of p-aminobenzoic acid as derivatizing agents. Ethyl p-aminobenzoate, the derivatizing agent used in many of our earlier studies, is one of these compounds. Our experiments using the hepatasaccharide maltoheptaose (M7) as a model oligosaccharide establish that by lengthening the alkyl chain from methyl to n-tetradecyl, a concomitant increase in the molecular ion abundance is obtained. The increase is a factor of 10 when 1 microgram of derivatized M7 is analyzed, and as much as 40 when 0.1 microgram of sample is examined. This series of derivatives of maltoheptaose form a suite of relatively abundant fragment ions in the negative ion mode as expected from our previous studies with the ethyl ester. Although very high mass spectral sensitivities were achieved with M7 n-tetradecyl and n-decyl p-aminobenzoates, the yields of derivative obtained were significantly lower than those obtained for M7 n-octyl, n-hexyl, n-butyl, ethyl, and methyl p-aminobenzoates, despite improvements made in the derivatization procedure. When analyzing biological samples, n-octyl and n-hexyl p-aminobenzoate were found to be optimal considering both yield of derivative and mass spectral sensitivity. This improved method of derivatization was incorporated into a simple but effective procedure for dealing with very small quantities of heterogeneous samples of oligosaccharides, such as those released from 250 micrograms (1 nmol) of nicotinic acetylcholine receptor from Torpedo californica and 90 micrograms (2 nmol) of human alpha 1 acid glycoprotein.

4-Aminobenzoic Acid↗
PubMed1998

Inhibitory actions of ellagic acid on growth and arylamine N-acetyltransferase activity in strains of Helicobacter pylori from peptic ulcer patients.

Arylamine N-acetyltransferase (NAT) activity in Helicobacter pylori was inhibited by ellagic acid, a possible chemopreventive drug. The NAT activity was determined using an acetyl CoA recycling assay and high pressure liquid chromatography. Inhibition of growth studies using H. pylori demonstrated that ellagic acid elicited a dose-dependent bactericidal effect in H. pylori cultures, i.e. the greater the concentration of ellagic acid, the greater the inhibition of growth of H. pylori. The IC50 value was 1 mM for inhibition of growth of H. pylori. Cytosols or suspensions of H. pylori with and without selected concentrations of ellagic acid co-treatment showed different percentages of 2-aminofluorene and p-aminobenzoic acid acetylation. The data indicated that there was decreased NAT activity associated with increased ellagic acid in H. pylori cytosols and intact cells. For the cytosol and intact bacteria examinations, the apparent values of K(m) and Vmax decreased after co-treatment with 1 mM ellagic acid. This report is the first demonstration of ellagic acid inhibition of arylamine NAT activity and ellagic acid inhibition of growth in the bacterium H. pylori.

4-Aminobenzoic Acid↗
PubMed1993

Inhibition of Pneumocystis carinii dihydropteroate synthetase by para-acetamidobenzoic acid: possible mechanism of action of isoprinosine in human immunodeficiency virus infection.

Isoprinosine has been reported to decrease progression to AIDS, primarily by preventing Pneumocystis carinii pneumonia (PCP), in human immunodeficiency virus-infected patients, but the mechanism of action is unknown. para-Acetamidobenzoic acid (PAcBA), one component of isoprinosine, is structurally related to para-aminobenzoic acid (PABA), a precursor of de novo folate synthesis. This pathway is known to be important for P. carinii because sulfonamides, which are effective anti-P. carinii agents, inhibit incorporation of PABA into folate precursors by the enzyme dihydropteroate synthetase (DHPS). Inhibition of P. carinii DHPS by PAcBA was investigated by using two assays. In short-term cultures of P. carinii from rats, [3H]PABA incorporation into reduced folates was inhibited by both isoprinosine (mean +/- standard error 50% inhibitory concentration [IC50], 20 +/- 8.4 microM) and PAcBA free acid (IC50, 240 +/- 100 microM); a soluble PAcBA salt was more potent than PAcBA free acid alone (IC50, 29 +/- 48 microM). The activity of PAcBA free acid was confirmed in a cell-free DHPS inhibition assay (IC50, 120 +/- 120 microM). Inosine and dimethylaminopropanol, two other components of isoprinosine, were poor inhibitors of PABA incorporation (IC50, > 1,000 microM). PAcBA free acid also showed activity in inhibiting the DHPS of Toxoplasma gondii, but was a poor inhibitor of the DHPSs of Escherichia coli and Saccharomyces cerevisiae. In a rat model of PCP, the PAcBA salt administered intraperitoneally demonstrated no activity against established PCP either alone or when used in combination with trimethoprim; the lack of efficacy in this model may be due to the rapid metabolism of the drug. Prevention of PCP by PaCBA through inhibition of P. carinii DHPS may explain the activity of isoprinosine in decreasing the progression to AIDS in human immunodeficiency virus-infected patients.

4-Aminobenzoic Acid↗
PubMed1987

Salmonella typhi 205aTy, a strain with two attenuating auxotrophic characters, for use in laboratory teaching.

The need for p-aminobenzoic acid of a previously reported pab mutant in a Salmonella typhi strain causes loss of virulence (mouse median lethal dose by the intraperitoneal route with mucin, ca. 10(7) CFU, versus less than 200 CFU for related pab+ strains). This strain, however, gave p-aminobenzoic acid-independent revertants at a low frequency (ca. 4 X 10(-10) per bacterium per generation). It was therefore given, by transduction and mutation, a transposon-generated, nonreverting (rate, less than 3 X 10(-11) per bacterium per generation) mutation at purA, causing a requirement for adenine; such a mutation in a wild-type strain caused about the same loss of virulence as the pab mutation. The pab purA strain, 205aTy, has mouse median lethal dose of ca. 5 X 10(7) and is expected to be unable to cause typhoid fever. Since strain 205aTy behaves like a typical Vi-positive S. typhi strain in nearly all common tests, we propose that it is a safe strain for use in laboratory teaching, proficiency testing, and the like.

4-Aminobenzoic Acid↗
PubMed1984

4-Methyl-3-hydroxyanthranilic acid activating enzyme from actinomycin-producing Streptomyces chrysomallus.

A 4-methyl-3-hydroxyanthranilic acid (4-MHA) activating enzyme was purified 24-fold from a crude protein extract of Streptomyces chrysomallus . The enzyme catalyzes both 4-MHA-dependent ATP/PPi exchange and the formation of the corresponding adenylate. No AMP was formed during the reaction, indicating that no covalent binding of 4-MHA takes place. Besides 4-MHA, the enzyme also catalyzes the formation of adenylates from 3-hydroxyanthranilic acid (3-HA), anthranilic acid (AA), benzoic acid (BA), 3-hydroxybenzoic acid (3-HB), 4-methyl-3-hydroxybenzoic acid (4-MHB), 4-methyl-3-methoxybenzoic acid (4- MMB ), and 4-aminobenzoic acid (4-AB). No such adenylates were formed from 2-aminophenol (2-AP), 2-hydroxybenzoic acid (2-HB), 3-hydroxykynurenine (3-HK), and tryptophan (Trp). 3-HA, 4-MHB, and 4-AB were among the structural analogues of 4-MHA that were the most effective for adenylate synthesis. In the case of 3-HA, considerable AMP release was observed, most probably due to nonenzymatic hydrolysis of the corresponding adenylate. A molecular weight between 53 000 and 57 000 was estimated. The specific activity of the enzyme was correlated with the titer of antibiotic in the cultures, and feeding experiments with whole mycelium of S. chrysomallus showed that 4-MHB was a strong inhibitor of actinomycin synthesis in vivo. The data strongly suggest that the enzyme is involved in the biosynthesis of actinomycin.

Adenosine Triphosphate↗
PubMed1993

The properties and function of gamma-glutamyl hydrolase and poly-gamma-glutamate.

gamma-Glutamyl hydrolase is a ubiquitous enzyme that has the capacity to cleave gamma-glutamyl bonds of cellular folyl- and antifolylpoly-gamma-glutamates. This study has revealed that the enzyme is secreted by primary cultures of rat hepatocytes and by H35 hepatoma cells. It was found that more than 99% of the total enzyme from H35 cells accumulated in the medium after 48 hr incubation with the serum-free medium. The cells were shown to remain intact during the secretion period since lactate dehydrogenase, dihydrofolate reductase and lysosomal hydrolases other than gamma-glutamyl hydrolase were retained within the cell. When PteGlu5 (folylGlu4) is used as a substrate the initial product is PteGlu (folate), and there is no appearance of intermediate chain length pteroyl polyglutamates. Therefore, the secreted and cellular gamma-glutamyl hydrolase from hepatoma cells appears to be an endopeptidase. Polyclonal antibodies to the poly-gamma-glutamate substrates of the enzyme were prepared and characterized. The antibodies recognize the structural differences between alpha- and gamma-glutamyl linkages but appear equally active with PteGlu5 and its analogs such as 4-NH2-10-CH3PteGlu5 and pABAGlu5. The affinity of the antibodies is related to the gamma-glutamyl structure since L-glutamic acid, folate or p-aminobenzoic acid are inactive with the antibodies. Furthermore, poly-gamma-glutamate has lower affinity for the antibodies than the poly-gamma-glutamate derivatives of PteGlu, 4-NH2-10-CH3PteGlu or pABA.

Animals↗
PubMed1975

Biosynthesis of p-aminophenylalanine: part of a general scheme for the biosynthesis of chorisimic acid derivatives.

p-Aminophenylalanine is biosynthesized in Vigna vexillata (L.) A. Rich. from shikimic acid through a pathway different from that giving phenylalanine and tyrosine. Experiments with 1,6-14C-labelled shikimic acid demonstrate that the C3-side chain in p-aminophenylalanine is attached to the original C-1 in shikimic acid. The biosynthesis of p-aminophenylalanine in Vigna vexillata probably follows the same pathway as the biosynthesis of this amino acid in Streptomyces species where it is known to be an intermediate in the biosynthesis of chloramphenicol. It is proposed that the biosynthesis takes place through chorismic acid, 4-amino-3-enolpyruvylcyclohexa-1,5-dienecarboxylic acid, 3-(4-amino-1-carboxycyclohexa-2,5-dienyl) pyruvic acid, and 4'-aminophenyl-yruvic acid. It is proposed that chorismic acid can gave rise to 4-amino-3-enolpyruvylcyclohexa-1,5-dienecarboxylic acid, 2-amino-3-enolpyruvylcyclohexa-4,6-dienecarboxylic acid, and isochorismic acid, and that these three compounds and chorismic acid itself by simple rearrangements and elimination reactions can give rise to most known chorismic acid derivatives, i. e.p-hydroxybenzoic acid, 3,4-dihydroxy-3,4-dihydrobenzoic acid, phenylalanine, tyrosine, p-aminobenzoic acid, p-aminophenylalanine, anthranilic acid, 2-amino-3-hydroxy-2,3-dihydrobenzoic acid, 3-(3-carobxyphenyl) alanine, 3-(3-carbocy-4-hydrocyphenyl) alanine, salicylic acid, and 2,3-dihydroxy2,3-dihydrobenzoic acid.

Amines↗
PubMed2001

Identification and functional characterization of arylamine N-acetyltransferases in eubacteria: evidence for highly selective acetylation of 5-aminosalicylic acid.

Arylamine N-acetyltransferase activity has been described in various bacterial species. Bacterial N-acetyltransferases, including those from bacteria of the gut flora, may be involved in the metabolism of xenobiotics, thereby exerting physiopathological effects. We characterized these enzymes further by steady-state kinetics, time-dependent inhibition, and DNA hybridization in 40 species, mostly from the human intestinal microflora. We report for the first time N-acetyltransferase activity in 11 species of Proteobacteriaceae from seven genera: Citrobacter amalonaticus, Citrobacter farmeri, Citrobacter freundii, Klebsiella ozaenae, Klebsiella oxytoca, Klebsiella rhinoscleromatis, Morganella morganii, Serratia marcescens, Shigella flexneri, Plesiomonas shigelloides, and Vibrio cholerae. We estimated apparent kinetic parameters and found that 5-aminosalicylic acid, a compound efficient in the treatment of inflammatory bowel diseases, was acetylated with a catalytic efficiency 27 to 645 times higher than that for its isomer, 4-aminosalicylic acid. In contrast, para-aminobenzoic acid, a folate precursor in bacteria, was poorly acetylated. Of the wild-type strains studied, Pseudomonas aeruginosa was the best acetylator in terms of both substrate spectrum and catalytic efficiency. DNA hybridization with a Salmonella enterica serovar Typhimurium-derived probe suggested the presence of this enzyme in eight proteobacterial and four gram-positive species. Molecular aspects together with the kinetic data suggest distinct functional features for this class of microbial enzymes.

Acetylation↗
PubMed2000

In vitro infection of Cryptosporidium parvum to four different cell lines.

To determine a suitable condition for in vitro infection model of Cryptosporidium parvum, four different cell lines, AGS, MDCK, HCT-8 and Caco-2, were used as host cell lines which were cultured at various concentrations of added supplements. These supplement include fetal bovine serum (FBS), sodium choleate, ascorbic acid, folic acid, calcium pantothenate, para-aminobenzoic acid and pyruvate and their effects on the cell lines which were infected with C. parvum were evaluated. The results of this study showed that the AGS cell line was most susceptible to C. parvum whereas the Caco-2 cells appeared to be least susceptible to C. parvum. In regards to the serum condition, 10% FBS was suitable for the growth of AGS and HCT-8 cells, and 1% FBS was good for the growth of the MDCK cells when they were inoculated with C. parvum. Vitamins had a positive effect on the AGS cells, and pyruvate also showed positive effects on all of the cell lines except for Caco-2. Modified medium for each cell line was prepared by adding appropriate amounts of each supplement which resulted in the highest parasite infection number. Modified media increased the number of parasites infected on AGS cells to 2.3-fold higher when compared to the control media. In this study, we found that the AGS cell line was a suitable host model for evaluating C. parvum in vitro study and the media contents for the optimal infection conditions were suggested.

Animals↗
PubMed1994

Directed biosynthesis of 5"-fluoropactamycin in Streptomyces pactum.

A new pactamycin analogue, 5"-fluoropactamycin, was prepared by directed biosynthesis. Supplementation of the fermentation medium of Streptomyces pactum, var. pactum with 3-amino-5-fluorobenzoic acid, an analogue of 3-aminobenzoic acid, an advanced precursor in pactamycin biosynthesis, resulted in co-production of pactamycin and the new pactamycin analogue. A similar feeding experiment with 3-amino-5-methylbenzoic acid did not result in formation of the corresponding methylated pactamycin analogue, but only in inhibition of pactamycin production. Comparison of antimicrobial and cytotoxic activities of pactamycin and 5"-fluoropactamycin showed no significant differences.

Animals↗
PubMed2002

Synthesis and biological activity of N(alpha)-[4-[N-[(3,4-dihydro-2-methyl-4-oxo-6-quinazolinyl)methyl]-N-propargylamino]phenylacetyl]-L-glutamic acid.

2-Deamino-2-methyl-N10-propargyl-5,8-dideazafolic acid (ICI 198583) is a potent inhibitor of thymidylate synthase. Its analogue, N(alpha)-[4-[N-[(3,4-dihydro-2-methyl-4-oxo-6-quinazolinyl)methyl]-N-propargylamino]phenylacetyl]-L-glutamic acid, containing p-aminophenylacetic acid residue substituting p-aminobenzoic acid residue, was synthesized. The new analogue exhibited a moderately potent thymidylate synthase inhibition, of linear mixed type vs. the cofactor, N(5,10)-methylenetetrahydrofolate. The Ki value of 0.34 microM, determined with a purified recombinant rat hepatoma enzyme, was about 30-fold higher than that reported for inhibition of thymidylate synthase from mouse leukemia L1210 cells by ICI 198583 (Hughes et al., 1990, J. Med. Chem. 33, 3060). Growth of mouse leukemia L5178Y cells was inhibited by the analogue (IC50 = 1.26 mM) 180-fold weaker than by ICI 198583 (IC50 = 6.9 microM).

Animals↗
PubMedDate not supplied

Liquid chromatographic determination of flucytosine in capsules: collaborative study.

A liquid chromatographic method for the determination of flucytosine in capsules was collaboratively studied by 7 laboratories. The method uses a C18 reverse phase column, water-methanol-acetic acid mobile phase containing 1-octanesulfonic acid sodium salt, p-aminobenzoic acid as internal standard, and photometric detection at 285 nm. The mean recovery value (+/- SD) of flucytosine from a synthetic formulation representing capsules was 99.2 +/- 1.72% (CV = 1.73%). Composited samples of 250 and 500 mg commercial capsules gave assay values of (mean +/- SD) 103.17 +/- 2.21 and 99.29 +/- 1.29% of declared, respectively. CV values were 2.15 and 1.30%. Reproducibility and repeatability CVs were 2.19 and 1.50%, respectively, for the 250 mg capsules, and 1.34 and 0.63%, respectively, for the 500 mg capsules. The method has been adopted official first action.

Capsules↗