PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Carboxylic Acids”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1979

Gustatory responses of eel palatine receptors to amino acids and carboxylic acids.

The gustatory receptors of the eel palate were found to be extremely sensitive to amino acids and carboxylic acids. The results obtained are as follows: (a) 11 amino acids which are among naturally occurring amino acids elicited responses in the palatine nerve, but 9 amino acids did not elicit a response even at a high concentration. The effect of D-amino acids was always much less than that of their corresponding L-isomers. There was no appreciable difference in the effectiveness of an alpha-amino acid (alpha-alanine) and beta-amino acid (beta-alanine). (b) The threshold concentrations of the most potent amino acids (arginine, glycine) were between 10(-8) and 10(-9) M. A linear relation between the magnitude of the response and log stimulus concentration held for a wide concentration range for all the amino acids examined. (c) The palatine receptors responded sensitively to various carboxylic acid solutions whose pH was adjusted to neutral. The threshold concentrations varied between 10(-4) and 10(-7) M. The magnitude of the response at 10(-2) M increased with an increase of carbon chain length. (d) The extent of cross-adaptation was examined with various combinations of amino acids. A variety of the response patterns showing complete cross-adaptation, no cross-adaptation, or synergetic interaction was observed. The synergetic interaction was also observed when one amino acid below its threshold concentration was added to the other amino acid below its threshold concentration was added to the other amino acid. No cross-adaptation was observed between amino acids and fatty acids. (e) The treatment of the palate with papain led to loss of the responses to arginine, glycine, and histidine without affecting those to proline and acetic acid. The treatment with pronase E eliminated selectively the response to proline. The possibility that the eel gustatory receptors are responsible for sensing food at a distance was discussed.

Adaptation, Physiological↗
PubMed1976

Gas chromatographic determination of carboxylic acid chlorides and residual carboxylic acid precursors used in the production of some penicillins.

An improved gas chromatographic method is described for the simultaneous determination of carboxylic acid chlorides and related carboxylic acids used in the production of some commercial semisynthetic penicillins. The acid chloride reacts with diethylamine to form the corresponding diethylamide. Carboxylic acid impurities are converted to trimethylsilyl esters. The two derivatives are separated and quantitated in the same chromatographic run. This method, an extension of the earlier procedure of Hishta and Bomstein (1), has been applied to the acid chlorides used to make oxacillin, cloxacillin, dicloxacillin, and methicillin (Figure 1); it shows promise of application to other acid chlorides. The determination is more selective than the usual titration methods, which do not differentiate among acids with similar pK's. Relative standard deviations of the acid chloride determination are 1.0-2.5%. Residual carboxylic acid can be repetitively determined within a range of 0.6% absolute.

Carboxylic Acids↗
PubMed1977

Preparation, identification, and quantitative NMR determination of silyl derivatives of 6-aminopenicillanic acid, 7-amino-3-methyl-delta3-cephem-4-carboxylic acid, and 7-amino-3-acetoxymethyl-delta3-cephem-4-carboxylic acid.

A rapid and accurate method for the quantitative determination of the extent and ratio of amino and carboxyl group trimethylsilylation of 6-aminopenicillanic acid, 7-amino-3-methyl-delta3-cephem-4-carboxylic acid, and 7-amino-3-acetoxymethyl-delta3-cephem-4-carboxylic acid is presented. The method utilizes NMR spectroscopy and is based on the difference in chemical shifts between N-trimethylsilyl and O-trimethylsilyl groups or, in cephalosporin derivatives, between the methyl group in the 3-position and free amino resonances. The spectra of the N,O-bis(trimethylsilyl) derivatives are discussed.

Cephalosporins↗
PubMed2025

Structural properties of short-chain carboxylic acids and alcohols relate to the molecular and physiological response of Salmonella enterica in an acidic environment.

Short-chain carboxylic acids (SCCA) and short-chain alcohols (SCALC) are naturally occurring antimicrobials that contribute to the biopreservation of food fermentations. This study investigated the effect of structurally different SCCA/SCALC with two-carbon (acetic acid; phenylacetic acid; 2-phenylethanol), three-carbon (propionic acid; 3-phenylpropionic acid; 3-phenylpropanol), and three-carbon chain with an additional hydroxyl group (lactic acid; 3-phenyllactic acid; 1-phenylpropanol) on the fitness, metabolic activity and gene expression of the pathogen Salmonella enterica at pH 4.5. SCCA inhibited Salmonella at lower concentrations than SCALC with the exception of lactic acid, which was partly consumed. The presence of a phenyl group enhanced antimicrobial activity. SCCA but not SCALC increased the lag phase of S. enterica, and in general, acetate was formed when cell growth was reduced by 20% suggesting a negative impact on bacteria fitness. Principal component analysis and hierarchical clustering indicated distinct gene expression profiles of S. enterica in response to SCCA or SCALC. In the presence of certain SCCA/SCALC, Salmonella activated pathways related to cellular pH control, and 1,2-propanediol, propionic acid and ethanolamine metabolism that involved the formation of metabolosomes. Genes related to flagellar assembly were less expressed and mobility was lower in the presence of lactic and 3-phenyllactic acid compared to controls suggesting a compound-specific response. KEY POINTS: • Differences in response among structurally different SCCA/SCALC at acidic condition. • SCCA/SCALC stress interfered with cell growth and metabolism of acetic and propionic acid. • Lactic acid prolonged the lag phase and reduced motility of Salmonella.

Salmonella enterica↗
PubMedDate not supplied

Oxidation of D-thiazolidine-4-carboxylic acid by hog kidney D-aminoacid oxidase.

D-Thiazolidine-4-carboxylic acid is a good substrate for hog kidney D-aminoacid oxidase. Data are presented showing that the only oxidation product is delta 3-thiazoline-4-carboxylic acid, which does not undergo further spontaneous degradation. Thus, the oxidation of D-thiazolidine-4-carboxylic acid by D-aminoacid oxidase differs considerably from the oxidation of its L-isomer catalyzed by rat liver mitochondria which gives as final product N-formylcystine, possibly through the intermediate delta 2-thiazoline-4-carboxylic acid.

Animals↗
PubMed1979

Syntheses and antiinflammatory actions of 4,5,6,7-tetrahydroindazole-5-carboxylic acids.

A novel series of 1-aryl-4,5,6,7-tetrahydro-1H-indazole-5-carboxylic acids and 2-aryl-4,5,6,7-tetrahydro-2H-indazole-5-carboxylic acids were synthesized via condensation between a phenylhydrazine and a 2-(hydroxymethylene)cyclohexanone-4-carboxylate, and the antiinflammatory activity was determined. In the carrageenan edema test, 1-aryl-4,5,6,7-tetrahydro-1H-indazole-5-carboxylic acids exhibited fairly high antiinflammatory activity. However, the 2-aryl isomers were far less active than the former. The most active compound of the series was 1-phenyl-4,5,6,7-tetrahydro-1H-indazole-5-carboxylic acid, which had an ED50 value of 3.5 mg/kg.

Analgesics↗
PubMed1979

Models of interaction between nucleic acids and proteins. Hydrogen bonding of arginine with nucleic acid bases, phosphate groups and carboxylic acids.

Complex formation between the side chain of arginine and nucleic acid bases has been investigated by proton magnetic resonance in dimethylsulfoxide. Simultaneous formation of two hydrogen bonds leads to a selectivity of arginine interaction towards cytosine and guanine. A comparison is made of the interaction of arginine side chain with nucleic acid bases, phosphate and carboxylate anions. It is shown that interaction between carboxylate and arginine is stronger than between phosphate and arginine. These results are discussed with respect to the selective recognition of nucleic acid bases by arginine side chains and by the arginyl-glutamyl ion pair which could form in proteins interacting with nucleic acids.

Arginine↗
PubMed1977

Glutamine as a precursor to N-terminal pyrrolid-2-one-5-carboxylic acid in mouse immunoglobulin lambda-type light chains. Amino acid-sequence variability at the N-terminal extra piece of lambda-type light-chain precursors.

The mRNA molecules coding for three mouse immunoglobulin lambda-type light (L) chains (MOPC-104E lambda(1), RPC-20 lambda(1), MOPC-315 lambda(2)) programme the cell-free synthesis of precursors larger than the mature proteins. Radioactive amino acid-sequence analyses of each of the three precursors labelled with [(3)H]alanine, [(3)H]serine, [(3)H]glutamine, [(3)H]glutamic acid and [(3)H]threonine showed that an extra piece, at least 18 residues long, is linked to the N-terminus of the mature L-chains. The N-terminal extra-peptide segment may be 19 residues long, since analyses of precursors labelled with [(35)S]methionine indicated an additional N-terminal methionine residue which was recovered in low yields. Presumably this is the initiator methionine, which is known to be short lived in eukaryotes. The mature forms of MOPC-104E, RPC-20 and MOPC-315 lambda L-chains are blocked at the N-termini by pyrrolid-2-one-5-carboxylic acid (pyroglutamic acid). Sequence analyses of precursors labelled with [(3)H]glutamine and [(3)H]glutamic acid showed incorporation only of glutamine in a position that matches with the position of pyrrolid-2-one-5-carboxylic acid in the mature forms of all three precursors, and incorporation of glutamic acid in other positions. The data showed the absence of glutamine-glutamic acid interconversion, since the radioactive peaks obtained from either (3)H-labelled amino acid were discrete, and free from cross-contamination. These results prove that glutamine is the precursor amino acid of pyrrolid-2-one-5-carboxylic acid at the N-termini of the mature MOPC-104E lambda(1), RPC-20 lambda(1) and MOPC-315 lambda(2) L-chains. Thus the formation of pyrrolid-2-one-5-carboxylic acid by cyclization of glutamine is a post-translational event which occurs after, or concomitant with, cleavage of the extra piece from the precursor to yield the mature L-chain. The variable (V) regions (110 amino acid residues) of mouse lambda L-chains are quite similar: when compared with that of MOPC-104E lambda(1) chain, the V-region of RPC-20 lambda(1) chain differs in one residue, and the V-region of MOPC-315 lambda(2) chain differs in 11 residues. The partial sequence data show that the N-terminal extra pieces of the two lambda(1) L-chain precursors have, so far, identical partial sequences; the extra piece of the lambda(2) L-chain precursor differs from these in at least three out of 19 positions.

Amino Acid Sequence↗
PubMed1979

Action of thiazolidine-2-carboxylic acid, a proline analog, on protein synthesizing systems.

Thiazolidine-2-carboxylic acid, or beta-thiaproline, is a proline analog in which the beta methylene group of proline is substituted by a sulfur atom. It has been deomonstrated that beta-thiaproline is activated and transferred to tRNAPro by Escherichia coli and rat liver aminoacyl-tRNA synthetases, and inhibits proline incorporation into polypeptides in protein synthesizing systems from E. coli, rat liver or rabbit reticulocytes. In mammalian systems beta-thiaproline inhibits also leucine incorporation; in rabbit reticulocyte lysate it inhibits ribosome run-off. Both these effects may be explained by the fact that beta-thiaproline once incorporated into the growing polypeptide chain impairs its further elongation, as shown by experiments made with puromycin. All tests were performed in comparison with thiazolidine-4-carboxylic acid, or gamma-thiaproline, another proline analog having the gamma methylene group substituted by a sulfur atom; it was shown that in all the reactions studied both compounds act as competitive inhibitors of proline. Some differences in the effects of the two analogs have been evidenced: in almost all the reactions and mainly in the whole protein synthesizing systems, beta-thiaproline shows an higher inhibitory activity.

Amino Acids, Sulfur↗
PubMed1979

Pharmacologically active sulfoximides: 5-hexyl-7-)S-methylsulfonimidoly) xanthone-2-carboxylic acid, a potent antiallergic agent.

The antiallergic activity of some xanthone derivatives containing a sulfoximide substitutent has been investigated. While 2-(S-methylsulfonimidoyl)xanthone itself was found to be inactive, a series of 7-(S-methylsulfonimidoly)-xanthone-2-carboxylic acids showed good levels of activity in the passive cutaneous anaphylaxis screen. N-Substituted sulfoximide derivatives were, without exception, less active than the corresponding unsubstituted compounds. The activity of the 7-(S-methylsulfonimidoyl)xanthone-2-carboxylic acids could be enhanced by the introduction of an alkyl or alkoxy substituent at C-5. As a result of these studies, 5-hexyl-7(S-methylsulfonimidoyl)xanthone-2-carboxylic acid has been selected for further investigation as an antipasthmatic agent.

Animals↗
PubMed1979

Antiallergy activity of substituted 11-oxo-11 H-pyrido[2,1-b]quinazoline-8-carboxylic acids.

A series of substituted 11-oxo-11H-pyrido[2,1-b]quinazoline-8-carboxylic acids were prepared and evaluated as antiallergy agents. Several analogues were orally active. 2-Methyl-11-oxo-11H-pyrido[2,1-b]quinoazoline-8-carboxylic acid (6) was superior to cromolyn sodium and doxantrazole orally and intravenously in the rat PCA test and a rat allergic bronchospasm model.

Animals↗
PubMed1977

[Mutagenic effect of new chemical compounds. IV. Mutagenic effect of dialkylaminoethyl esters of 5,6-dihydro-7H-benz(c)carbazol-carboxylic acids].

The mutagenic effect of dialkylaminoet hyl esters of 5,6-dihydro-7H-benz(c)carbazole-carboxylic acids on biochemical mutants (Escherichia coli P-678, Actinomyces rimosus 222) is found. Hydrochloride of diethylaminoethyl ester of 5,6-dihydro-7H-benz(c)carbazole-9-carboxylic acid, which induced reversible and direct mutations, proved to be the most active compound, its mutagenic activity exceeding considerably the activity of ethylene imine.

Aziridines↗
PubMed1978

Antiallergic activity of tetracyclic derivatives of quinoline-2-carboxylic acid. 2. Some benzothienoquinolinecarboxylic acids.

Some benzothienoquinolinecarboxylic acids were synthesized and tested in the rat passive cutaneous anaphylaxis (PCA) assay as potential antiallergic agents. Many of the compounds showed activity comparable to that shown by disodium cromoglycate (DSFG); two of them, 1,4-dihydro-4,6,6-trioxo-5-chloro[1]benzothieno[2,3-g]quinoline-2-carboxylic acid and 1,4-dihydro-1,7-dioxo[1]benzothieno[3,2-f]quinoline-3-carboxylic acid, showed potency approximately eightfold greater than that of DSCG in the PCA assay.

Animals↗