INHIBITORS OF THE β-GLUCURONIDASE OF RABBIT POLYMORPHONUCLEAR LEUCOCYTES

1951 ◽  
Vol 29 (4) ◽  
pp. 195-207
Author(s):  
Esther Wong ◽  
R. J. Rossiter

As previously reported, rabbit polymorphonuclear leucocytes contain an enzyme capable of hydrolyzing biosynthetic phenolphthalein mono-β-glucuronide. The effect of a number of inhibitors on cell-free preparations of this enzyme was studied. Many of the usual enzyme inhibitors were without effect, but certain dicarboxylic acids were strong inhibitors. These were (in order of activity): D-glucosaccharic acid, D-mucic acid, L-malic acid, mesotartaric acid, DL-malic acid, and L-tartaric acid. The nature of the inhibition was competitive. The Michaelis constant, Ks, was evaluated for phenolphthalein mono-β-glucuronide and values of Ki were estimated for glucosaccharic acid, mucic acid, DL-malic acid, and mesotartaric acid. Heparin in high concentration was slightly inhibitory, but the nature of the inhibition was noncompetitive. For each of the inhibitors studied, the extent of the inhibition was influenced by the hydrogen ion concen tration. At a pH greater than 4.5, the optimum for the enzyme under the conditions used, the degree of inhibition was less, and at a pH less than 4.5 the degree of inhibition was greater.

Atmosphere ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1703
Author(s):  
Kei Sato ◽  
Fumikazu Ikemori ◽  
Sathiyamurthi Ramasamy ◽  
Akihiro Fushimi ◽  
Kimiyo Kumagai ◽  
...  

To better understand precursors of dicarboxylic acids in ambient secondary organic aerosol (SOA), we studied C4–C9 dicarboxylic acids present in SOA formed from the oxidation of toluene, naphthalene, α-pinene, and isoprene. C4–C9 dicarboxylic acids present in SOA were analyzed by offline derivatization gas chromatography–mass spectrometry. We revealed that C4 dicarboxylic acids including succinic acid, maleic acid, fumaric acid, malic acid, DL-tartaric acid, and meso-tartaric acid are produced by the photooxidation of toluene. Since meso-tartaric acid barely occurs in nature, it is a potential aerosol tracer of photochemical reaction products. In SOA particles from toluene, we also detected a compound and its isomer with similar mass spectra to methyltartaric acid standard; the compound and the isomer are tentatively identified as 2,3-dihydroxypentanedioic acid isomers. The ratio of detected C4–C5 dicarboxylic acids to total toluene SOA mass had no significant dependence on the initial VOC/NOx condition. Trace levels of maleic acid and fumaric acid were detected during the photooxidation of naphthalene. Malic acid was produced from the oxidation of α-pinene and isoprene. A trace amount of succinic acid was detected in the SOA produced from the oxidation of isoprene.


1950 ◽  
Vol 28e (3) ◽  
pp. 69-79 ◽  
Author(s):  
R. J. Rossiter ◽  
Esther Wong

Rabbit polymorphonuclear leucocytes contain an enzyme capable of hydrolyzing biosynthetic phenolphthalein mono-β-glucuronide. The concentration of the enzyme in the white cell is some 2000 times the concentration of the enzyme in the blood plasma. Under the conditions of study, the β-glucuronidase activity was proportional to the concentration of the enzyme. The effect of substrate concentration on the enzyme activity was studied and the Michaelis constant, Ks, determined. The course of the reaction was linear with time for the first 12 hr. and then fell off slightly during the next 12 hr. The optimum pH of the enzyme was 4.45 in either 0.2 M acetate or 0.2 M phthalate buffer. It was not inhibited by cyanide, azide, iodoacetate, fluoride, glycine, thiourea, urethane, arsanilic acid, acetophenone, o-cresol or m-cresol, in a final concentration of 0.01 M. The possible function of β-glucuronidase in rabbit polymorphonuclear leucocytes is discussed.


1988 ◽  
Vol 21 (11) ◽  
pp. 2049-2067 ◽  
Author(s):  
Tak-Lung Chang ◽  
Robert P. Streicher ◽  
Hans Zimmer ◽  
J. W. Munch

1962 ◽  
Vol 115 (1) ◽  
pp. 37-47 ◽  
Author(s):  
Hans Klaus Kaiser ◽  
W. Barry Wood

The production of endogenous pyrogen by intact granulocytes obtained from acute peritoneal exudates is blocked by arsenite, iodoacetate, p-chloromercuribenzoate, and N-ethylmaleimide in concentrations of 2 x 10–4 M. When the concentration of these sulfhydryl-reactive enzyme inhibitors is increased to 2 x 10–2 M, only the iodoacetate inactivates the pyrogen molecule, whereas the arsenite, the p-chloromercuribenzoate, and the N-ethylmaleimide have no gross effect upon its thermogenic activity. Both diisopropyl fluorophosphate and dinitrofluorobenzene are even more potent inactivators of the pyrogen molecule than iodoacetate, although the action of the DFP cannot be blocked or reversed by known antagonists such as 2-pyridine aldoxime methiodide and hydroxylamine. Proteolytic enzymes, potentially capable of degrading leucocytic pyrogen, are released from polymorphonuclear leucocytes, along with the pyrogen, when the cells are incubated in normal salt solution. These enzymes are readily activated by a sufficient concentration of glutathione (2 x 10–2 M). They are not present in preparations of partially purified leucocytic pyrogen from which much of the non-pyrogenic protein has been removed. Glutathione by itself, even at concentrations as high as 2 x 10–1 M, does not affect in the gross the thermogenic activity of the purified pyrogen. The implications of these findings in relation to both the production and the chemical characteristics of leucocytic pyrogen are discussed.


2014 ◽  
Vol 68 (8) ◽  
Author(s):  
Eugenia Teodor ◽  
Georgiana Badea ◽  
Andreia Alecu ◽  
Larisa Calu ◽  
Gabriel Radu

AbstractExperimentally developed ceramic pots, with two different sizes of grain, were half-filled with wine and subjected to thermal alteration at constant elevated temperature ((60 ± 2)°C) in darkness for 12 weeks. This work sought to characterise the samples thereby obtained from chemical and mineralogical perspectives using scanning electron microscopy and an energy-dispersive X-ray microanalysis system (SEM-EDX), Fourier transform infrared spectroscopy (FTIR) and capillary electrophoresis (CE) with UV detection as an alternative to chromatographic methods, due to its good resolution, automation, simplicity, high speed, low consumption of chemicals and short time required for sample preparation. The capillary electrophoresis method was used for the detection of five wine biomarkers: succinic acid, malic acid, tartaric acid, citric acid and lactic acid. In general, it was noted that the fine-grained ceramic assortment retained the organic material better than the coarser-grained ceramics. An interesting observation derived from this study was that not only could tartaric acid be considered as a biomarker for wine residues in archaeological pottery, but malic acid could also act similarly for white wine and lactic acid for red wine.


1985 ◽  
Vol 68 (5) ◽  
pp. 902-905
Author(s):  
Taizo Tsuda ◽  
Hiroshi Nakanishi ◽  
Takashi Morita ◽  
Junko Takebayashi

Abstract A method was developed for simultaneous gas chromatographic determination of sorbic acid, dehydroacetic acid, and benzoic acid used as preservatives, and succinic acid, fumaric acid, malic acid, and tartaric acid used as acidulants in soft drinks and jams. A sample was dissolved in NH4OH-NH4CI pH 9 buffer solution, and an aliquot of the solution was passed through a QAE-Sephadex A 25 column. The column was washed with water, and the carboxylic acids were eluted with 0.1N HC1. Sorbic acid, dehydroacetic acid, and benzoic acid were extracted with ethyl ether-petroleum ether (1 + 1), and determined on a 5% DEGS + 1% H3PO4 column. Succinic acid, fumaric acid, malic acid, and tartaric acid in the lower layer were derivatized with N,0- bis(trimethylsilyl)acetamide and trimethylchlorosilane, and determined on a 3% SE-30 column. Recoveries from soft drink and jam samples fortified with 0.1% each of 7 carboxylic acids ranged from 92.4 to 102.6% for preservatives, and from 88.1 to 103.2% for acidulants.


2001 ◽  
Vol 67 (9) ◽  
pp. 4144-4151 ◽  
Author(s):  
Carole Camarasa ◽  
Frédérique Bidard ◽  
Muriel Bony ◽  
Pierre Barre ◽  
Sylvie Dequin

ABSTRACT In Saccharomyces cerevisiae, l-malic acid transport is not carrier mediated and is limited to slow, simple diffusion of the undissociated acid. Expression in S. cerevisiae of the MAE1 gene, encodingSchizosaccharomyces pombe malate permease, markedly increased l-malic acid uptake in this yeast. In this strain, at pH 3.5 (encountered in industrial processes),l-malic acid uptake involves Mae1p-mediated transport of the monoanionic form of the acid (apparent kinetic parameters:V max = 8.7 nmol/mg/min;Km = 1.6 mM) and some simple diffusion of the undissociated l-malic acid (Kd = 0.057 min−1). As total l-malic acid transport involved only low levels of diffusion, the Mae1p permease was further characterized in the recombinant strain. l-Malic acid transport was reversible and accumulative and depended on both the transmembrane gradient of the monoanionic acid form and the ΔpH component of the proton motive force. Dicarboxylic acids with stearic occupation closely related to l-malic acid, such as maleic, oxaloacetic, malonic, succinic and fumaric acids, inhibitedl-malic acid uptake, suggesting that these compounds use the same carrier. We found that increasing external pH directly inhibited malate uptake, resulting in a lower initial rate of uptake and a lower level of substrate accumulation. In S. pombe, proton movements, as shown by internal acidification, accompanied malate uptake, consistent with the proton/dicarboxylate mechanism previously proposed. Surprisingly, no proton fluxes were observed during Mae1p-mediated l-malic acid import inS. cerevisiae, and intracellular pH remained constant. This suggests that, in S. cerevisiae, either there is a proton counterflow or the Mae1p permease functions differently from a proton/dicarboxylate symport.


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