SEARCH · PubMed Health

Results for “TRICHLOROACETIC ACID”

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 829 records · Page 46Linked to original sources

PubMed1978

Interaction of phospholipid vesicles with rat hepatocytes in primary monolayer culture.

We studied the interaction of positively and negatively charged unilamellar and multilamellar phospholipid vesicles (liposomes) with rat-liver parenchymal cells in primary monolayer culture. Radioactive liposomal phosphatidylcholine was taken up more rapidly and to a larger extent from unilamellar than from multilamellar vesicles. No significant difference in uptake characteristics was observed between vesicles of different charge. The presence of serum greatly reduced uptake of liposomal phosphatidylcholine of both unilamellar and multilamellar vesicles. This serum effect was independent of surface charge of the vesicles. When cells were allowed to take up radioactive liposomal phospholipid and then incubated further in absence of vesicles, part of the radioactivity associated with the cells was released into the medium, most of it as water soluble degradation products. When cells were preincubated with vesicles containing horseradish peroxidase and then, after removal of the vesicles, further incubated, peroxidase activity could be demonstrated in the culture medium, part of it only after addition of Triton X-100. These observations were taken to indicate that part of the phospholipid taken up the cells represented vesicles binding to the cell surface rather than having been internalized. Vesicle-entrapped [125I]albumin was taken up by the cells and rapidly hydrolyzed as indicated by the appearance of radioactivity soluble in trichloroacetic acid within minutes after starting the incubation. No uptake of free albumin could be demonstrated. The kinetics of albumin uptake and release of trichloroacetic acid-soluble radioactivity from the cells suggest that, initially, liposomes are internalized predominantly by endocytosis, while during prolonged incubation fusion of the liposomal membrane with the plasma membrane gradually contributes more substantially to the overall uptake process. The significance of these findings is emphasized with special reference to the use of liposomes as intravenous carriers of enzymes or drugs.

Blood↗

PubMed1988

Thioacylating agents as ultimate intermediates in the beta-lyase catalysed metabolism of S-(pentachloro-butadienyl)-L-cysteine.

The transformation of the hexachloro-1,3-butadiene metabolite S-(1,2,3,4,4-pentachlorobuta-1,3-dienyl)-L-cysteine (PCBC) by bacterial cysteine conjugate beta-lyase (beta-lyase) and by N-dodecylpyridoxal bromide (PLP-Br) was investigated using GC/MS to identify products formed. PCBC was transformed by both bacterial beta-lyase and PLP-Br to the major products 2,3,4,4-tetrachlorobutenoic acid and 2,3,4,4-tetrachlorothiobutenoic acid, and to the minor metabolites trichloroacetic acid and S-(1,2,3,4,4-pentachlorobuta-1,3-dienyl)-mercaptoacetic acid. In the presence of diethylamine as model nucleophile, PLP-Br transformed PCBC to yield 2,3,4,4-tetrachlorothiobutenoic acid diethylamide; attempts to trap 1,2,3,4,4-pentachlorobutadienyl thiol, the initial metabolite formed by beta-elimination from PCBC, were unsuccessful. The results obtained suggest that the formation of a thioacylating intermediate (a thioketene or a thiono acyl chloride) may be the decisive reaction during the beta-lyase dependent activation of PCBC.

Butadienes↗

PubMed1985

Accumulation of N-acetylneuraminic acid (sialic acid) in human fibroblasts cultured in the presence of N-acetylmannosamine.

Human skin fibroblasts incubated for 72 h in medium containing 10 mM N-acetyl-D-mannosamine accumulate material that yields a chromophore in the presence of thiobarbituric acid. This material was tentatively identified as free (unbound) sialic acid due to its reactivity with thiobarbituric acid prior to acid hydrolysis, its solubility in 10% trichloroacetic acid, its chromatographic properties on an anion-exchange column and its enzymatic susceptibility to acylneuraminate pyruvate-lyase. Mass spectrometry analysis established that the accumulated material was, in fact, N-acetylneuraminic acid. Loading studies demonstrated a linear relationship between the amount of N-acetylmannosamine in the medium and the level of sialic acid accumulating within the cells. Cells grown in the absence of N-acetylmannosamine contained an average of 5 nmol free sialic acid/mg protein, while cells cultured for 72 h in 20 mM amounts of this material contained an average of 156.3 nmol free sialic acid/mg protein. When the cells were removed from the N-acetylmannosamine-enriched medium and incubated in regular medium, more than 80% of the accumulated, intracellular sialic acid disappeared within the first 96 h. It was concluded from these data that normal fibroblasts cultured in medium enriched with N-acetylmannosamine store large amounts of N-acetylneuraminic acid and can thus serve as an excellent model for the study of both normal and abnormal sialic acid metabolism, transport, storage and/or metabolic (feedback) regulation in human tissue.

Biological Transport, Active↗

PubMed2000

Role of aldehyde dehydrogenases in endogenous and xenobiotic metabolism.

Aldehydes are highly reactive molecules that are intermediates or products involved in a broad spectrum of physiologic, biologic and pharmacologic processes. Aldehydes are generated from chemically diverse endogenous and exogenous precursors and aldehyde-mediated effects vary from homeostatic and therapeutic to cytotoxic, and genotoxic. One of the most important pathways for aldehyde metabolism is their oxidation to carboxylic acids by aldehyde dehydrogenases (ALDHs). Oxidation of the carbonyl functional group is considered a general detoxification process in that polymorphisms of several human ALDHs are associated a disease phenotypes or pathophysiologies. However, a number of ALDH-mediated oxidation form products that are known to possess significant biologic, therapeutic and/or toxic activities. These include the retinoic acid, an important element for vertebrate development, gamma-aminobutyric acid (GABA), an important neurotransmitter, and trichloroacetic acid, a potential toxicant. This review summarizes the ALDHs with an emphasis on catalytic properties and xenobiotic substrates of these enzymes.

Aldehyde Dehydrogenase↗

PubMed1999

Preconcentration and separation of haloacetic acids by ion chromatography.

A comparative study was made of the chromatographic behaviour of five haloacetic acids (mono-, dibromoacetic and mono-, di-, trichloroacetic acids). The techniques investigated included reversed-phase ion interaction chromatography with UV detection, suppressed and non-suppressed anion-exchange chromatography. The systems are discussed studying the retention as a function of the mobile phase parameters and the stationary phases used (LiChrospher 100 RP-18, IonPac AS9, AS10 and AS11). A preconcentration step, performed on different substrates, namely LiChrolut-EN and activated vegetal carbon, has been optimized in order to reduce the method detection limits. Results obtained for drinking water samples are shown.

Acetates↗

PubMed2002

Quantitation of tryptophan, kynurenine and kynurenic acid in human plasma by capillary liquid chromatography-electrospray ionization tandem mass spectrometry.

Concentrations of tryptophan and its metabolites in plasma are of great interest in determining proper diagnosis and medication of several neurological diseases like, for example, Alzheimer's disease. A method of standard addition was developed to determine total level of tryptophan and two of its metabolites, kynurenine and kynurenic acid, in human plasma by capillary liquid chromatography-electrospray ionization tandem mass spectrometry. Plasma samples were simply deproteinized by addition of diluted perchloric acid. Samples were then mixed with trichloroacetic acid and injected onto a capillary column. Analytes were separated by a fast gradient elution of the injected samples. Detection was performed by sheathless electrospray tandem mass spectrometry in the multiple reaction monitoring mode. Linear calibration curves were obtained for spiked plasma sample with up to 100% of the expected analytes concentrations. The determined concentrations were well within ranges previously reported (i.e., 6 nM-95 microM) and limit of detections were around 3 nM for each analyte.

Calibration↗

PubMed2005

Fenton degradation of organic compounds promoted by dyes under visible irradiation.

The influence of dyes on the Fenton reaction of organic compounds under visible irradiation (lambda > 450 nm) was examined. It was found that the presence of dyes could accelerate greatly the Fenton reaction of organic compounds such as salicylic acid, sodium benzenesulfonate, benzyltrimethylammonium chloride, and trichloroacetic acid under visible irradiation and that a complete mineralization of those compounds could also be achieved. The dyes such as Alizarin Violet 3B which has an anthraquinone structure unit showed much more significant effect on the reaction than the dyes such as malachite green without the quinone unit. A reaction mechanism of dye AV as a cocatalyst in the photo-Fenton reaction of organic compounds under visible irradiation is proposed based on the cycle of Fe(3+)/Fe(2+) catalyzed by quinone species and an electron transfer from the excited dye molecule to Fe3+.

Coloring Agents↗

PubMed1965

The molecular structure of bacterial walls. The size of ribitol teichoic acids and the nature of their linkage to glycosaminopeptides.

1. Ribitol teichoic acids prepared by fractional precipitation of trichloroacetic acid extracts of bacterial cell walls are essentially undegraded and have similar chain length to the teichoic acid originally present in the walls. 2. The chain length of teichoic acid can be determined directly, without prior extraction from the wall. Accurate values have been obtained by measurement of the formaldehyde produced by oxidation of walls with periodate. Less accurate values have been derived from the amount of inorganic phosphate formed by heating walls at pH4. 3. The relative amounts of N-acetylglucosaminylribitol and its mono- and di-phosphates produced by heating walls of Staphylococcus aureus with alkali agree with the amounts calculated for the hydrolysis of teichoic acid having the chain length determined by other methods. 4. Chemical considerations indicate that the linkage between teichoic acid and the wall may involve a phosphoramidate bond between the terminal phosphate of the teichoic acid and one of the amino groups in the glycosaminopeptide.

Cell Wall↗

PubMed1973

Insulin biosynthesis in the bullhead, Ictalurus nebulosus, and the effect of temperature.

Insulin biosynthesis in the brown bullhead, Ictalurus nebulosus (Le Sueur), was studied by measuring the incorporation in vitro of [(3)H]leucine into proteins of the principal islet. The tissue was incubated for 6-15h in Krebs-Ringer bicarbonate buffer with [(3)H]leucine, supplemented with amino acids and glucose. Proteins, precipitated with trichloroacetic acid and extracted with acid ethanol, were separated by gel-filtration on Biogel P-30 in 3m-acetic acid. Three major components were found after incubation of the islets at 22 degrees C. On the basis of the results of sulphitolysis, biological activity and the demonstrated precursor-product relationship, components I and II were identified as proinsulin and insulin respectively. The third component was not identified. At 12 degrees C, [(3)H]leucine was incorporated only into proinsulin. No radioactivity was found in insulin or the unidentified component III at 12 degrees C as was found after incubation at 22 degrees C. When the temperature was lowered from 22 degrees to 12 degrees C after 3h of a 15h incubation, decreased conversion of proinsulin into insulin resulted at the lower temperature compared with the control tissue maintained at 22 degrees C. When the temperature was raised from 12 degrees to 22 degrees C at 3h of a 15h incubation, conversion of proinsulin into insulin occurred. No conversion occurred in the control tissue with the temperature maintained at 12 degrees C. No qualitative difference in the incorporation of [(3)H]leucine into proinsulin and its conversion into insulin at 12 degrees and 22 degrees C could be demonstrated between islet tissue from fish acclimated to less than 12 degrees C or to 22 degrees C. The results suggest that the enzyme(s) responsible for converting proinsulin into insulin in the bullhead may be temperature sensitive with low activity at 12 degrees C.

Amino Acids↗

PubMed1969

Membranes of animal cells. 3. Amino acid incorporation by isolated surface membranes.

Surface membranes isolated from mouse fibroblasts contain RNA organized in ribosome-like particles. These surface membranes can incorporate radioactive amino acids into material insoluble in hot trichloroacetic acid. Characterization of the radioactive products indicated that they are large polypeptides. Most requirements and inhibitors of the system were similar to those of the microsomal system of the endoplasmic reticulum. Further comparisons were made with microsomal and pH 5 fractions prepared from L-cells by standard procedures and by two methods attempting to simulate the conditions necessary for isolating surface membranes. The amount of L-leucine incorporated by the surface membranes per mg of RNA was comparable to the values obtained by the microsomal and pH 5 fractions prepared by standard procedures. In contrast, the activity of the two other microsomal fractions was less than 10 per cent of this amount. The most striking difference noted was in the products formed by the surface membranes and by the microsomal systems. These products were demonstrated to be quite different by electrophoresis on acrylamide gels. It is suggested that the surface membranes participate actively in protein synthesis in vivo, and that, because of this location, the protein-synthesizing mechanism may be able to perform special functions more efficiently.

Amino Acids↗

PubMed1994

Microheterogeneous Cytosolic High-Mobility Group Proteins from Broccoli Co-Purify with and Are Phosphorylated by Casein Kinase II.

A group of low molecular weight protein substrates was found to co-purify with casein kinase II from broccoli (Brassica oleracea var italica). These substrates showed very high affinity toward casein kinase II and were efficiently phosphorylated even in the presence of an excess of exogenous substrates. The broccoli substrates were purified from cytosolic extracts as a double band of related proteins migrating at 18.7 and 20 kD. Further microheterogeneity was revealed by anion-exchange high-performance liquid chromatography and mass spectroscopy. The actual molecular masses of the three major components identified by mass spectroscopy were determined to be 12,691, 13,256, and 14,128 D. The substrates showed characteristic amino acid composition with a high content of polar amino acids, including about 20% each of acidic and basic amino acids. They were soluble in 2% trichloroacetic acid. The substrates cross-reacted with an antibody against wheat high-mobility group protein d (HMGd) but not HMGa. The isolated broccoli HMGs showed general DNA-binding activity without preference for AT-rich DNA. The presence of these HMG proteins in the cytosolic fraction is similar to the distribution characteristics of the animal HMG-1 subgroup. On the basis of amino acid composition and DNA-binding specificity, the isolated broccoli HMGs resemble other plant HMGs homologous to the HMG-1 subgroup.

Journal Article↗

PubMed1986

Protein-synthesizing activity of maize-shoot chromatin : I. Conditions and component requirements.

The evidence presented in this paper suggests that purified plant chromatin, similar to mammalian (SR Umansky et al., Eur J Biochem 1980 105: 117-129), has the ability to incorporate amino acids into acid precipitable material. The polypeptide-synthesizing system of chromatin seems to differ substantially from the classical polyribosomal translation mechanism in cytoplasm. When chromatin purified from 5-day-old etiolated maize (Zea mays) shoots was incubated with (14)C-labeled amino acids, label was incorporated into the trichloroacetic acid precipitable product. Chloramphenicol, pactamycin, and actinomycin D inhibited the incorporation almost completely, whereas treatment with cycloheximide, puromycin, or aurintricarboxylic acid did not affect the labeling. Preincubation with pancreatic RNase was also without effect, but treatment of chromatin with DNase I caused about 25% depression of label incorporation. A wheat germ translation system or its single components have no effect on the chromatin polypeptide-synthesizing activity beyond that expected for a simple addition. The protein-synthesizing system is tightly bound to chromatin and could not be removed by dissociation in 1 molar NaCl. The mean molecular weight of the major protein fraction synthesized in the presence of chromatin was 21 to 24 kilodaltons.

Journal Article↗

PubMed2006

Analysis of the Arabidopsis rsr4-1/pdx1-3 mutant reveals the critical function of the PDX1 protein family in metabolism, development, and vitamin B6 biosynthesis.

Vitamin B6 represents a highly important group of compounds ubiquitous in all living organisms. It has been demonstrated to alleviate oxidative stress and in its phosphorylated form participates as a cofactor in >100 biochemical reactions. By means of a genetic approach, we have identified a novel mutant, rsr4-1 (for reduced sugar response), with aberrant root and leaf growth that requires supplementation of vitamin B6 for normal development. Cloning of the mutated gene revealed that rsr4-1 carries a point mutation in a member of the PDX1/SOR1/SNZ (for Pyridoxine biosynthesis protein 1/Singlet oxygen resistant 1/Snooze) family that leads to reduced vitamin B6 content. Consequently, metabolism is broadly altered, mainly affecting amino acid, raffinose, and shikimate contents and trichloroacetic acid cycle constituents. Yeast two-hybrid and pull-down analyses showed that Arabidopsis thaliana PDX1 proteins can form oligomers. Interestingly, the mutant form of PDX1 has severely reduced capability to oligomerize, potentially suggesting that oligomerization is important for function. In summary, our results demonstrate the critical function of the PDX1 protein family for metabolism, whole-plant development, and vitamin B6 biosynthesis in higher plants.

Amino Acid Sequence↗

PubMed1966

Endogenous metabolism of Azotobacter agilis.

Sobek, J. M. (University of Southwestern Louisiana, Lafayette), J. F. Charba, and W. N. Foust. Endogenous metabolism of Azotobacter agilis. J. Bacteriol. 92:687-695. 1966-Ribonucleic acid, deoxyribonucleic acid, cellular carbohydrate, and the cold trichloroacetic acid and acidic alcohol fractions of the cell do not appear to function as endogenous reserves for Azotobacter agilis. The immediate endogenous reserve of cells grown on glucose, acetate, or succinate was poly-beta-hydroxybutyric acid (PHB). Viability of the cells during starvation was dependent upon the initial levels of PHB and the growth substrate. Cells with high initial PHB levels survived longer than cells with lower levels. Cells from succinate-grown cultures had lower PHB levels than cells from glucose-grown cultures, but were capable of maintaining their viability longer. Cellular protein may also serve as a secondary endogenous reserve substrate for this organism.

Acetates↗

PubMed1998

[Structure of the bacterial cell wall].

The fine structure of the cell walls of Gram-positive and -negative bacteria were determined by electron microscopy with the new technique of freeze substitution method, and analysed the cell wall structure of Staphylococcus aureus in detail. The surface of Staphylococcal cell wall was covered with a fuzzy coat consisting of fine fibers or electron-dence mass. This coat was completely removed after extraction of teichoic acid from the cell wall with trichloroacetic acid treatment, but was not affected by sodium dodecyl sulfate or trypsin treatment. It was suggested that many amount of teichoic acid was located on the surface of the cell wall and less inside the cell wall. The capsule of strain Smith diffuse was assumed to play the role as the barrier protected from the penetration of antibody against teichoic acid.

Cell Wall↗

PubMed1989

Determination of guanine by high-performance liquid chromatography with electrochemical detection: application to DNA and RNA assays.

A highly sensitive assay for guanine was developed using high-performance liquid chromatography with electrochemical detection (ECD). Guanine was susceptible to the electrochemical oxidation, and ECD response was proportional to the amount of guanine in the range 0.25-4 pmol of guanine. The ECD of guanine was applicable to the analysis of nucleic acids. DNA and RNA were hydrolyzed in 0.03 and 3 M HCl, respectively, and guanine liberated from the nucleic acids was separated on a reverse-phase column and determined by ECD. The method allowed detection of 0.2 ng of calf thymus DNA or tRNA. An application of the method is shown for DNA and RNA assays in trichloroacetic acid extracts of rat adrenal and liver.

Adrenal Glands↗

PubMed1998

Antimutagenicity and the influence of physical factors in binding Lactobacillus gasseri and Bifidobacterium longum cells to amino acid pyrolysates.

Antimutagenic and binding properties of 28 strains of Lactobacillus gasseri and 2 strains of Bifidobacterium longum on the mutagenicity of amino acid pyrolysates were investigated in vitro using a streptomycin-dependent (SD510) strain of Salmonella typhimurium TA 98. Four strains of L. acidophilus (SBT0274, SBT1703, SBT10239, and SBT10241) and 1 strain of B. longum (SBT 2928) exhibited the highest percentage of antimutagenicity and binding. These 5 strains were further optimized for other physical factors influencing the mechanism of binding, such as cell and mutagen concentration, pH, and incubation time. In all of the selected strains, 2 mg of cells bound with 88 to 95% of 0.2 mg of 3-amino-1,4 dimethyl-5H-pyrido[4,3-b]indole in 30 min at pH 7.0. Other amino acid pyrolysates, such as 3-amino-1-methyl-5H-pyrido[4,3-b]indole, 2-amino-6-methyldi-pyrido[1,2-a:3',2'-d]imidazole, 2-amino-3-methyl-imidazo[4,5,f]quinoline, and 2-amino-3,4-dimethyl-imidazo[4,5,f]quinoline were also tested for the binding ability of these strains. We observed that the complexity of the mutagens greatly influenced the binding properties. The binding of 3-amino-1,4 dimethyl-5H-pyrido[4,3-b]indole to the purified cell walls was very high compared with that of the crude cell wall, peptidoglycan, or the cell extract. Binding was inhibited when the cell walls were subjected to treatment with metaperiodate or trichloroacetic acid but not when they were subjected to treatment with lysozyme, trypsin, or proteinase K, reflecting the role of the carbohydrate component as a binding site.

Amino Acids↗

PubMed1994

A partition coefficient determination method for nonvolatile chemicals in biological tissues.

Partition or distribution coefficients are critical elements in efforts designed to describe the uptake, distribution, biotransformation, and excretion of organic chemicals in biological systems. In order to estimate the partition coefficients needed to describe the biological distribution of low-volatility compounds, an experimental method was developed to measure partitioning of nonvolatile compounds into biological tissues. Blood, fat, muscle, liver, and skin were individually incubated in a saline solution containing the chemical of interest. Each sample was centrifuged and 2.0 ml of the supernatant was removed and placed into a prewashed, low binding 10,000 MW cutoff Millipore filter cell. Each cell was fitted with a magnetic stirrer and 32 psi nitrogen was applied to the closed cell. The filtrate was collected, extracted, and analyzed for the chemical of interest. The chemicals evaluated were parathion, lindane (hexachlorocyclohexane), paraoxon, perchloroethylene, trichloroacetic acid, and dichloroacetic acid. These chemicals were chosen to develop this method because their vapor pressures range from 9 x 10(6) to 14.2 mm Hg at 20 degrees C. For the one volatile chemical evaluated, perchloroethylene, the method provided partition coefficient results that were in good agreement with values obtained using the vial equilibration method. The nonvolatile partition coefficient method described in this paper demonstrates an approach for evaluation of chemicals with diverse chemical structure and solubility properties.

Animals↗