Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: CAS:75-07-0 (aldehyde)
25,023 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The metabolism of several N-nitrosamines (N-nitrosodimethylamine, N-nitrosoethylmethylamine, N-nitrosodiethylamine, N-nitrosobenzylmethylamine, and N-nitrosopyrrolidine) in cultured human and rat esophagus has been investigated by measuring (a) CO2, (b) metabolites with an oxo group, and (c) metabolites bound to DNA. Both acyclic and cyclic N-nitrosamines were metabolized by rat esophagus. The highest level of metabolite binding was seen with N-nitrosobenzylmethylamine, an organotrophic carcinogen for the rat esophagus. The binding level was about 100-fold higher than in human esophagus. This compound methylated rat esophageal DNA at positions 7 and O6 of guanine. The level of benzylation in rat was one-tenth of the level of methylation. Formation of benzaldehyde exceeded that of formaldehyde plus CO2 by a factor of six, indicating that the methylene group was preferentially oxidized. N-Nitrosoethylmethylamine, another unsymmetrical N-nitrosamine, was preferentially oxidized by rat esophagus in the ethyl group, as shown by higher formation of CO2 and acetaldehyde from the compound labeled in the ethyl group. The highest binding level to DNA from this compound was observed with the methyl group. No binding was detected to human esophagus. N-Nitrosopyrrolidine was oxidized by both rat and human esophagus in the alpha position, as measured by the formation of 2,4-dinitrophenylhydrazone derivative of 4-hydroxybutanal. Binding of metabolites of N-nitrosopyrrolidine to DNA was detected only in rat esophagus. As measured by the formation of both CO2 and formaldehyde, N-nitrosodimethylamine was metabolized by both human and rat esophagus. While most of the radioactivity associated with DNA was found to be incorporated into guanine and adenine, methylation of the guanine positions 7 and O6 was detected by chromatography of the hydrolyzed rat DNA. The results indicate significant quantitative and perhaps qualitative differences between cultured rat and human esophagus in their ability to activate N-nitrosamines, although unknown physiological differences after culture may contribute to this difference.
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PMID:Metabolism of N-nitrosamines by cultured human and rat esophagus. 706 9

An enzyme with NAD+-dependent 4-aminobutyraldehyde dehydrogenase activity was purified about 360-fold from rat brain extract. AMP-Sepharose chromatography was effective in separating the enzyme from other NAD+-dependent aldehyde dehydrogenases included in the extract. The KmS for the substrates NAD+ and 4-aminobutyraldehyde were 4.8 x 10(-4) and 8.3 x 10(-5) M, respectively. The pH optimum for the enzyme was about 8.0. The ratio of activities toward 4-aminobutyraldehyde, propionaldehyde, succinate semialdehyde, and benzaldehyde was 1.00:0.17:0.24:0.09:0.03 when the activity toward 4-aminobutyraldehyde was set equal to 1.00. The enzyme activity in subcellular fractions of rat brain was localized in cytosol.
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PMID:4-Aminobutyraldehyde dehydrogenase activity in rat brain. 709 87

A soluble aldehyde dehydrogenase (EC 1.2.1.3) was partially purified from Rhizobium japonicum bacteroids and from free-living R. japonicum 61A76. The enzyme was activated by NAD+, NADH, and dithiothreitol, and it reduced NAD(P)+. Acetaldehyde, propionaldehyde, butyraldehyde, benzaldehyde, and succinic semialdehyde were substrates. The Km for straight-chain aldehydes decreased with increasing carbon chain length. The aldehyde dehydrogenase was inhibited by 6-cyanopurine, but not by metronidazole. These compounds inhibited acetylene reduction, but not respiration, by isolated bacteroids.
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PMID:Soluble aldehyde dehydrogenase and metabolism of aldehydes by soybean bacteroids. 720 1

1. Based on the decay characteristics of short-lived gamma-emitting radioisotopes a new acute exposure method was developed for studying the kinetics and biodistribution of inhaled toxic agents. Such body-penetrating radiation allows direct, non-invasive determination of the radiation in the animal at any time. 2. Rats exposed to 11C-labelled benzaldehyde for 2 min accumulated an average of 2.5 micrograms of this aldehyde. 3. Inhaled benzaldehyde was rapidly absorbed and at 1.5 min after exposure only 0.8% of the administered dose was resident in the lungs. This aldehyde was quickly distributed with the peak radioactivity in the organs occurring at 1.5 min after exposure. Subsequent loss of radiolabel from tissues was rapid and paralleled the removal from the blood. The adipose tissue cleared most slowly. 4. Benzaldehyde was rapidly excreted via the renal system with the kidneys containing 17% of the total administered activity at 5 min. The excreted radiolabelled compound co-chromatographed with hippuric acid on t.l.c.
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PMID:Biodistribution and excretion of [11C]benzaldehyde by the rat after two-minute inhalation exposures. 741 9

Desulfovibrio gigas NCIMB 9332 cells grown in ethanol-containing medium with 0.1 microM tungstate contained a benzylviologen-linked aldehyde oxidoreductase. The enzyme was purified to electrophoretic homogeneity and found to be a homodimer with a subunit M(r) of 62,000. It contained 0.68 +/- 0.08 W, 4.8 Fe, and 3.2 +/- 0.2 labile S per subunit. After acid iodine oxidation of the purified enzyme, a fluorescence spectrum typical for form A of molybdopterin was obtained. Acetaldehyde, propionaldehyde, and benzaldehyde were excellent substrates, with apparent Km values of 12.5, 10.8, and 20 microM, respectively. The natural electron acceptor is not yet known; benzylviologen was used as an artificial electron acceptor (apparent Km, 0.55 mM). The enzyme was activated by potassium ions and strongly inhibited by cyanide, arsenite, and iodoacetate. In the as-isolated enzyme, electron paramagnetic resonance studies readily detected W(V) as a complex signal with g values in the range of 1.84 to 1.97. The dithionite-reduced enzyme exhibited a broad signal at low temperature with g = 2.04 and 1.92; this is indicative of a [4Fe-4S]1+ cluster interacting with a second paramagnet, possibly the S = 1 system of W(IV). Until now W-containing aldehyde oxidoreductases had only been found in two Clostridium strains and two hyperthermophilic archaea. The D. gigas enzyme is the first example of such an enzyme in a gram-negative bacterium.
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PMID:Purification and characterization of a benzylviologen-linked, tungsten-containing aldehyde oxidoreductase from Desulfovibrio gigas. 759 85

As the physiologic roles for the different classes of aldehyde dehydrogenase (ALDH) enzymes are elucidated, the identification of specific, reversible inhibitors becomes of great pharmacologic interest. Previous structure-function studies identified dialkylamino substituted benzaldehyde compounds as a novel class of reversible inhibitors of class I ALDH. To examine further structural requirements for inhibition, we tested a series of 4-(N,N-dialkylamino)benzaldehyde analogs as inhibitors of propanal oxidation by mouse liver and human erythrocyte class I ALDH. 4-(N,N-dipropylamino)benzaldehyde (DPAB) was identified as the most potent, reversible inhibitor of propanal oxidation by class I ALDH in spectrophotometric enzyme assays. In kinetic studies, DPAB showed mixed-type inhibition with respect to the aldehyde substrates propanal, phenylacetaldehyde, benzaldehyde, and aldophosphamide. DPAB exhibited uncompetitive inhibition with respect to the cofactor NAD. Inhibition constants (Ki) for DPAB, estimated from Dixon plots, were 10 nM (propanal) and 77 nM (phenylacetaldehyde) for mouse ALDH and 3 nM (propanal) and 70 nM (phenylacetaldehyde) for human ALDH. These Ki values are 100-fold lower than those reported for class I specific inhibitors. At low (< 1 microM) DPAB concentrations, inhibition of propanal and aldophosphamide oxidation was > 75%, whereas inhibition of benzaldehyde (32%) and phenylacetaldehyde (19%) oxidation was reduced markedly. These results indicate that DPAB exhibits potent, reversible inhibition of mouse and human class I ALDH. The degree of inhibition was highly dependent on the structure of the aldehyde substrate.
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PMID:Identification of 4-(N,N-dipropylamino)benzaldehyde as a potent, reversible inhibitor of mouse and human class I aldehyde dehydrogenase. 764 41

Although considerable research has been performed on the thermal degradation products of polyethylene, no data that can be compared to occupational exposure limits have been reported on the exposure of workers in commercial polyethylene extrusion operations. In this study, the actual airborne concentrations of previously identified analytes were measured during the commercial-scale processing of polyethylene resins. Nine polyethylene resins, spanning LDPE, LLDPE, and HDPE product slates were processed under commercial-scale conditions appropriate to their application: blown film, extrusion coating, blow molding, pipe extrusion, and rotational molding. Air samples were taken from operator breathing zones and of representative workplace air and contained air (inside film bubbles and molded parts) using recognized occupational health and safety protocols. The compounds selected for monitoring consisted of aldehydes (formaldehyde, acetaldehyde, acrolein, butyraldehyde, crotonaldehyde, and benzaldehyde), aromatics (benzene, toluene, xylenes, and styrene), formic and acetic acids, furan and tetrahydrofuran, and acetone. Airborne particulates also were measured. Of the 450 concentration measured from workplace air and operator breathing zones, 440 were below detection limits. Nine of the remaining ten concentrations were < 10% of the established exposure limits, while one particulate measurement was < 50% of the established exposure limit. As well, 180 contained-air samples were taken. Off-gases trapped inside film bubbles and molded parts accumulated to concentrations above those measured in the ambient air. It was concluded that polyethylene extrusion presents minimal inhalation hazards in a moderately ventilated environment.
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PMID:Quantitation of employee exposure to emission products generated by commercial-scale processing of polyethylene. 765 36

The archaeon Pyrococcus furiosus grows optimally at 100 degrees C by the fermentation of carbohydrates to yield acetate, CO2, and H2. Cell-free extracts contain very low activity of the glycolytic enzyme, glyceraldehyde-3-phosphate dehydrogenase, but extremely high activity of glyceraldehyde-3-phosphate ferredoxin oxidoreductase (GAPOR). GAPOR was purified under strictly anaerobic conditions. It is a monomeric, O2-sensitive protein of M(r) approximately 63,000 which contains pterin and approximately 1 tungsten and 6 iron atoms per molecule. The enzyme oxidized glyceraldehyde-3-phosphate (Km 28 microM) to 3-phosphoglycerate and reduced P. furiosus ferredoxin (Km 6 microM), but it did not oxidize formaldehyde, acetaldehyde, glyceraldehyde, benzaldehyde, glucose, glucose 6-phosphate, or glyoxylate, nor did it use NAD(P) as an electron acceptor. It is proposed that GAPOR has a glycolytic role and functions in place of glyceraldehyde-3-phosphate dehydrogenase and possibly phosphoglycerate kinase.
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PMID:Glyceraldehyde-3-phosphate ferredoxin oxidoreductase, a novel tungsten-containing enzyme with a potential glycolytic role in the hyperthermophilic archaeon Pyrococcus furiosus. 772 30

Two aldehyde dehydrogenases involved in the degradation of toluene and xylenes, namely, benzaldehyde dehydrogenase and 2-hydroxymuconic semialdehyde dehydrogenase, are encoded by the xylC and xylG genes, respectively, on TOL plasmid pWW0 of Pseudomonas putida. The nucleotide sequence of xylC was determined in this study. A protein exhibiting benzaldehyde dehydrogenase activity had been purified from cells of P. putida (pWW0) (J. P. Shaw and S. Harayama, Eur. J. Biochem. 191:705-714, 1990); however, the amino-terminal sequence of this protein does not correspond to that predicted from the xylC sequence but does correspond to that predicted from the xylG sequence. The protein purified in the earlier work was therefore 2-hydroxymuconic semialdehyde dehydrogenase (the xylG gene product). This conclusion was confirmed by the fact that this protein oxidized 2-hydroxymuconic semialdehyde (kcat/Km = 1.6 x 10(6) s-1 M-1) more efficiently than benzaldehyde (kcat/Km = 3.2 x 10(4) s-1 M-1). The xylC product, the genuine benzaldehyde dehydrogenase, was purified from extracts of P. putida (pWW0-161 delta rylG) which does not synthesize 2-hydroxymuconic semialdehyde dehydrogenase. The amino-terminal sequence of the purified protein corresponds to the amino-terminal sequence deduced from the xylC sequence. This enzyme efficiently oxidized benzaldehyde (kcat/Km = 1.7 x 10(7) s-1 M-1) and its analogs but did not oxidize 2-hydroxymuconic semialdehyde or its analogs.
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PMID:Overlapping substrate specificities of benzaldehyde dehydrogenase (the xylC gene product) and 2-hydroxymuconic semialdehyde dehydrogenase (the xylG gene product) encoded by TOL plasmid pWW0 of Pseudomonas putida. 786 91

A simple, selective and sensitive high-performance liquid chromatographic (HPLC) method has been developed for the measurement of josamycin residues in four porcine tissues (i.e., muscle, liver, kidney and fat). The sample preparation consisted of a homogenization step in an acetonitrile-10 mmol l-1 phosphate buffer mixture, pH 6.0 (35 + 65), centrifugation and a liquid-liquid extractive clean-up of the resulting supernatant with isooctane. Pre-column derivatization of josamycin was performed using cyclohexa-1,3-dione in ammonium acetate buffer, pH 5.0 (90 degrees C for 2 h). The derivative was chromatographed in an isocratic reversed-phase HPLC system. A LiChrospher RP 18 end-capped (5 microns) column was eluted with an acetonitrile-methanol-10 mmol l-1 phosphate buffer mixture, pH 6.0 (45 + 5 + 50). The capacity factor of the josamycin derivative was 17.5. Detection was achieved using spectrofluorimetry (lambda ex = 375 nm; lambda em = 450 nm). The structure of the derivative was assessed by using mass spectrometry. Full selectivity was obtained in the HPLC system versus other macrolide antibiotics (tylosin, spiramycin and erythromycin), aldehydes (formaldehyde, acetaldehyde and benzaldehyde) and endogenous compounds. Linearity and repeatability were tested. Correlation coefficients, for calibration curves in the range of 0.1-3.2 micrograms g-1, were greater than 0.999 for all tissues and the relative standard deviation (S(r)) was 4.9% (1.6 micrograms g-1; n = 6); recovery was higher than 88%.
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PMID:Determination of josamycin residues in porcine tissues using high-performance liquid chromatography with pre-column derivatization and spectrofluorimetric detection. 787 87


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