Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “DIMETHYLAMINOAZOBENZENE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the 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
PubMed1989

Reversed-phase high-performance liquid chromatography separation of dimethylaminoazobenzene sulfonyl- and dimethylaminoazobenzene thiohydantoin-amino acid derivatives for amino acid analysis and microsequencing studies at the picomole level.

A simple and fast reversed-phase high-performance liquid chromatographic method has been developed for the complete separation of 35 dimethylaminoazobenzene sulfonyl (DABS)-amino acids and by-products. This method allows simultaneous determination of primary and secondary amino acids which can be present in protein and peptide hydrolysates and also detects the presence of cysteic acid, S-sulfocysteine, hydroxyproline, taurine, norleucine, cystine, and delta-hydroxylysine. The precolumn derivatization of amino acids with dimethylaminoazobenzene sulfonyl chloride (DABS-Cl) is simple and quick (10 min at 70 degrees C) and allows the complete reaction of primary and secondary amino acids. The separation of the compounds under investigation is achieved in 25 min using a reversed-phase 3-microns Supelcosil LC-18 column at room temperature. The versatility of the proposed method is documented by amino acid determination on protein samples obtained using different hydrolysis techniques (HCl, methane-sulfonic acid, and NaOH), with attention given to the detection of tryptophan in protein samples with high sugar concentration. Furthermore, we have reported the experimental conditions necessary to apply this method to the amino acid analysis of very low amount of proteins (1 to 5 micrograms) electroeluted from a stained band after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The stability of DABS-derivatives, the short time of analysis, the high reproducibility and sensitivity of the system, and the complete resolution of all compounds of interest make this method suitable for routine analysis. Furthermore, we have also developed a fast reversed-phase high-performance liquid chromatographic method for the complete separation of dimethylaminoazobenzene thiohydantoin (DABTH)-amino acids. The separation of the compounds under investigation is obtained, at room temperature, in less than 18 min using a reversed-phase Supelcosil LC-18 DB column, 3-micron particles, and also allows the complete separation of DABTH-Ile, DABTH-Leu, and DABTH-Norleu. The short time of analysis, together with the high reproducibility of the system and its sensitivity at picomole levels, make this method very suitable for the identification of DABTH-amino acids released during microsequencing studies of proteins and peptides with the dimethylaminoazobenzene isothiocyanate reagent. In addition, we have shown that it is possible to obtain complete separation of DABTH-amino acids also under isocratic conditions.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acids↗
PubMed1975

A comparison of the effects of 3'-methyl-4-dimethylaminoazobenzene, 2-methyl-4-dimethylaminoazobenzene, and 2-acetylaminofluorene on rat liver DNA stability and new synthesis.

The objective of the present study was to define early biochemical changes occuring in livers of rats that were fed various chemical carcinogens. Rats were subjected to partial hepatectomy and subsequently given multiple injections of radioactive thymidine to prelabel DNA in their liver. Following a 4-week recovery period the rats were placed on either basal diets or diets containing either 0.05% 3'-methyl-4-dimethylaminoazobenzene (3'-MeDAB), 0.028% 2-acetylaminofluorene, or 0.05% 2-methyl-4-dimethylaminoazobenzene for various periods. After 5 weeks 3'-MeDAB had caused a dose-dependent loss of prelabeled DNA demonstrating the cytotoxicity of this carcinogen. The comparatively noncarcinogenic 2-methyl-4-dimethylaminoazobenzene caused only a small loss of prelabeled DNA. In contrast, the hepatocarcinogen 2-acetylaminofluorene did not cause a loss of prelabeled DNA, demonstrating its low cytotoxicity. Autoradiography and histology revealed that the loss of prelabeled DNA in livers of rats fed 3'-MeDAB was largely due to parenchymal cell death. Experiments designed to separate liver regenerative hyperplasia from neoplastic hyperplasia revealed the presence of both an early and a delayed elevation of thymidine incorporation into liver DNA in rats fed 0.05% 3'-MeDAB. An "early" elevation of incorporation occurred during and shortly after 3'-MeDAB feeding, and a "delayed" elevation of incorporation occurred some weeks after the dye was discontinued. Autoradiography revealed that parenchymal cells were largely responsible for the increased incorporation. Feeding of 2-methyl-4-dimethylaminoazobenzene depressed thymidine incorproation. A direct comparison of the effects of isomolar levels of 3'-MeDAB and 2-acetylaminogluorene on hepatic hyperplasia indicated that both carcinogens caused comparable increases in thymidine incorporation, which returned to control levels upon feeding of carcinogen-free diet. The differences and similarities between the responses to the three compounds are discussed and considered with regard to initiation and promotion of hepatoma formation.

Animals↗
PubMed1981

The effects of pre-incubation period and norharman on the mutagenic potency of 4-dimethylaminoazobenzene and 3'-methyl-4-dimethylaminoazobenzene in S. typhimurium.

The effects of the co-mutagen norharman on the mutagenicity of the rodent liver carcinogens 4-dimethyl-aminoazobenzene (DAB) and 3'-methyl-4-dimethyl-aminoazobenzene (3'-MeDAB) have been evaluated using the Ames Salmonella mutation assay. A period of pre-incubation was found to be necessary in order to detect DAB as a mutagen and to increase the initially weak response observed for 3'MeDAB; maximum responses were seen after 1 h pre-incubation in each case. The co-mutagenic properties of norharman were at their maximum for both azo-dyes in the direct plate-incorporation assay. Pre-incubation of either compound with norharman for increasing periods of time resulted in a decrease in potentiation, until after 1 h, an inhibition of mutagenicity was observed.

Alkaloids↗
PubMed1976

4-NN-dimethylaminoazobenzene 4'-isothiocyanate, a new chromophoric reagent for protein sequence analysis.

4-NN-Dimethylaminoazobenzene 4'-isothiocyanate was synthesized for the purpose of improving the ease and sensitivity of peptide sequence analysis. The method of 4-NN-dimethylaminoazobenzene 4'-isothiocyanate synthesis, the preparation of 24 4-NN-dimethylaminoazobenzene-4'-thiohydantoins of amino acids and their t.l.c. separation are described. All the thiohydantoins, except those of leucine and isoleucine, could be satisfactorily separated by chromatography on a two-dimensional polyamide sheet. The sensitive azo group permits the detection of 4-NN-dimethylaminoazobenzene-4'-thiohydantoins of amino acids as red spots down to pmol amounts directly on the sheet. A simple sensitive method for sequencing dipeptides and the first two or three N-terminal amino acids of proteins is also reported. The colour change of the spots from purple to blue to red after being exposed to HCl vapour, corresponding to the chemical change from 4-NN-dimethylaminoazobenzene-4' isothiocyanate to the 4-NN-dimethylaminoazobenzene-4'-thiocarbamoyl amino acid derivative to the 4-NN-dimethylaminoazobenzene-4'-thiohydantoin amino acid derivative, reveals a very interesting and valuable feature of this reagent.

Amino Acid Sequence↗
PubMed1961

Fine structural alterations in cell particles during chemical carcinogenesis. III. Selective action of hepatic carcinogens other than 3'-methyl-4-dimethylaminoazobenzene on different types of mitochondrial swelling. Effect of stimulated liver growth.

The previous studies on the correlation between tumor incidence and changes in microsomal and mitochondrial swelling during feeding of 3'-methyl-4-dimethylaminoazobenzene to rats have been extended to other hepatic carcinogens. Administration of 4'-fluoro-4-dimethylaminoazobenzene, 4'-ethyl-2-methyl-4-dimethylaminoazobenzene, 2-acetylam-inofluorene, ethionine, and tannic acid were found to produce drastic alterations of the swelling of rat liver mitochondria. In contrast to these compounds, feeding of the non-carcinogenic azobenzene and 4-diethylaminoazobenzene produced only small changes in swelling. Significant modification in the over-all pattern of the swelling curve was observed when the usual concentration of 3'-methyl-4-dimethylaminoazobenzene was reduced, but not when the riboflavin level in the diet was increased tenfold. Feeding of high levels of this dye to the guinea pig did not affect mitochondrial swelling which is consistent with the resistance of this species to azo-dye carcinogenesis. Hypophysectomy provides protection against the alterations, produced by feeding 3'-methyl-4-dimethylaminoazobenzene, in the characteristics of thyroxine- or mercuric chloride-induced mitochondrial swelling. Studies with citric cycle substrates on mitochondrial swelling suggest block of the glutamate right harpoon over left harpoon alpha-keto-glutarate pathway after feeding 3'-methyl-4-dimethylaminoazobenzene for 4 weeks. There is a considerable, but reversible, reduction of certain types of mitochondrial swelling in two situations associated with rapid liver growth: after partial hepatectomy and after intraperitoneal injection of 20-methylcholanthrene. Naphthacene, however, which also stimulates rapid liver growth, does not affect mitochondrial swelling.

Animals↗
PubMed1979

Interactions of small molecules with phospholipid bilayers. Binding to egg phosphatidylcholine of some uncharged molecules (2-acetylaminofluorene, 4-dimethylaminoazobenzene, oestrone and testosterone) that bind to ligandin and aminoazo-dye-binding protein A.

1. To assess the possible involvement of ligandin and aminoazo-dye-binding protein A in intracellular transport it is necessary to know how their ligands, most of which are molecules with hydrophobic moieties, interact with cellular membranes. To obtain such information we have examined the interactions of 2-acetylaminofluorene, 4-dimethylaminoazobenzene, oestrone and testosterone with aqueous dispersions of egg phosphatidylcholine and egg phosphatidylcholine/cholesterol (1:1, molar ratio) by equilibrium dialysis and spectrophotometry. 2. At 25 degrees C and pH7.4, the partition coefficients for binding to phosphatidylcholine [expressed as (mol of ligand bound/mol of phosphatidylcholine)/unbound ligand concentration] were: for 2-acetylaminofluorene, 5.0x10(3) litre.mol(-1); for 4-dimethylaminoazobenzene, 2.1x10(4) litre.mol(-1); for oestrone, 3.1x10(3) litre.mol(-1); and for testosterone, 4.2x10(2) litre.mol(-1). In the ranges studied these values were independent of concentration. The results for the two steroids confirm those of Heap, Symons & Watkins [(1970) Biochim. Biophys. Acta218, 482-495]. 3. The introduction of cholesterol into the lipid bilayers caused large decreases in the partition coefficients of oestrone and testosterone, but had relatively little effect on the binding of 2-acetylaminofluorene and 4-dimethylaminoazobenzene. 4. By assuming that the interactions with egg phosphatidylcholine bilayers resemble those with the phospholipid components of mammalian intracellular membranes the phosphatidylcholine partition coefficients, together with data for binding to the intracellular proteins ligandin and aminoazo-dye-binding protein A, enable the subcellular distributions of the four compounds to be estimated. For the rat hepatocyte up to 98, 99, 89 and 58% of the total 2-acetylaminofluorene, 4-dimethylaminoazobenzene, oestrone and testosterone respectively may be membrane-bound.

2-Acetylaminofluorene↗
PubMed1982

Effect of drugs and hormones on rat liver dimethylaminoazobenzene reductase activity.

1. Rat liver endoplasmic reticulum catalyzes the reduction of 4-dimethylaminoazobenzene (DAB) by NADPH to dimethyl-p-phenylenediamine and p-aminophenol. This azoreductase activity was inhibited by cyanide and cytochrome b5 antibody, but was resistant to carbon monoxide and SKF-525A (beta-diethylaminoethyl-diphenylpropylacetate). 2. DAB azoreductase activity was induced by 20-methylcholanthrene and phenobarbital, and increased in streptozotocin-induced diabetes or fasting. It was repressed by treatment with DAB and its 3'-methyl derivative, but not by several other derivatives with substitutions in the dimethylaminoazobenzene ring. 3. Azoreductase activity, NADPH-cytochrome P-450 reductase, cytochromes P-450 and b5 were measured in liver microsomes prepared from fasted animals and from animals treated with 20-methylcholanthrene, phenobarbital, streptozotocin or 3-aminotriazole plus allyl-isopropylacetamide. No direct correlation could be established between the variations of azoreductase activity and those of cytochromes P-450 and b5, and of NADPH-cytochrome P-450 reductase in these experimental situations. Since these known carriers do not seem to be the limiting factors for the azoreductase activity, the participation of an unknown carrier that can be repressed by dimethylaminoazobenzene is postulated. 4. Dimethylaminoazobenzene treatment did not reduce the rate of synthesis of microsomal proteins but rather increased the turnover rate of proteins with molecular weights of about 17, 30 an 35 kdal. Since streptozotocin increased the synthesis of proteins with molecular weights of 17, 32, and 48 kdal it is suggested that one of these proteins may correspond to the postulated carrier that is the limiting factor in DAB reduction.

Allylisopropylacetamide↗
PubMed1989

Analysis of 4-N,N-dimethylaminoazobenzene 4'-thiohydantoin amino acids at sub-picomole levels by high-performance liquid chromatography: simultaneous manual sequencing of picomole quantities of several polypeptides.

A single-column high-performance liquid chromatographic separation of 4-N,N-dimethylaminoazobenzene 4'-thiohydantoin amino acid derivatives, generated during polypeptide sequence analysis by the 4-N,N-dimethylaminoazobenzene 4'-isothiocyanate/phenylisothiocyanate double coupling technique, is described. Recovery of the serine and threonine derivatives was improved by substituting boron trifluoride-diethyl etherate for trifluoroacetic acid in the thiazolinone cleavage reactions. Residues, including the S-carboxymethyl derivative of cysteine, were assigned after a single injection and a cycle time of 30 min. Quantities of 4-N,N-dimethylaminoazobenzene 4'-thiohydantoin amino acid derivatives as low as 100 fmol were detected. Interference of sequencing artefacts with residue assignment was avoided. This technique allows simultaneous manual sequencing of several proteins or peptides at the level of a few picomoles.

Amino Acid Sequence↗
PubMed1975

Binding of the azocarcinogen 3'-methyl-p-dimethylaminoazobenzene to cellular components of normal rat liver and azocarcinogen-induced hepatomas.

The location of binding sites for 3'-methyl-p-dimethylaminoazobenzene (3'-Me-DAB) or metabolites on components of rat liver cells and hepatoma cells in tumors induced by this carcinogen was determined at 2 stages during the induction of tumors in rats: (a) in normal liver immediately following the application of a massive dose of the azocarcinogen by intragastric feeding, and (b) in liver and tumor after hepatomas had developed following repeated exposures to the carcinogen by s.c. injections. Bound 3'-Me-DAB or metabolites were detected by the use of rabbit antisera directed against either p-azoazobenzene or p'-azo-p-dimethylaminoazobenzene in an indirect fluorescent antibody technique. Soon after massive intragastric doses of 3'-Me-DAB, the staining observed when the anti-p-azoazobenzene antiserum was used was principally on cytoplasmic components of liver cells with some staining of the intranuclear components. When the second antiserum, anti-p'-azo-p-dimethylaminoazobenzene antiserum, was used, the most intense fluorescent staining was on the nuclear membranes, although there was some cytoplasmic and intranuclear staining as well.

Adenoma, Bile Duct↗