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At least 19 recordsLinked to original sources
PubMed1978

Photolytic inhibition and labeling of proteins with aryl diazonium compounds.

In the course of preparing aryl azide derivatives for use as photoprobes, we have observed significant light sensitivity in the precursor aryl diazonium compounds. The photosensitive properties of this class of compounds are of interest since they will seek out cationic binding sites in biological targets, and can be employed to inhibit complementary targets at acid pH. The relationship between photolytic change in the structure of diazonium compounds and the corresponding change in function of a biological target are presented. Experiments are described in which the dark and light sensitive properties of a model diazonium compound, diazobenzene sulfonate (DBS), were determined. The ultraviolet spectra were used to evaluate the dark stability and light sensitivity of DBS. Chymotrypsin and trypsin served as functioning targets for further evaluation of the photochemical properties. Both enzymes are stable to the probe in the dark at acid pH. A rapid loss of enzyme activity was observed following flash photolysis of DBS-enzyme solutions. Photolytic incorporation of radioactive DBS into chymotrypsin was observed. Aryl diazonium salts can be employed to probe the availability of complementary sites in biological targets at different acid pH values.

Chymotrypsin↗
PubMed1976

A colour reaction for the differentiation of ascomycetous and hemibasidiomycetous yeasts.

Seventy yeast strains, representative of twenty-six ascogenous genera, four saprobic hemibasidiomycetous genera and thirteen genera of the Cryptococcales were tested for their reaction with the stabilized aromatic diazonium compound, Diazonium Blue B salt. An aqueous, buffered solution of this compound gave a characteristic red colouration with the colonies of the hemibasidiomycetous species and those Cryptococcales characterized by the hemibasidiomycetous cell-wall type. The characteristic colour reaction was not observed with colonies of either the ascomycetous yeasts or those Cryptococcales characterized by the ascomycetous cell-wall type. The possibly taxonomic use of the colour reaction with Diazonium Blue B salt as an affinitive characteristic is discussed.

Ascomycota↗
PubMed1987

Aryl diazo compounds and diazonium salts as potential irreversible probes of the gamma-aminobutyric acid receptor.

The synthesis of different diazonium salts derived from homo- and heterocyclic aromatic amines bearing anionic residues is described. The chemical stabilities of these compounds were established at different pH's, and the compounds were tested accordingly in binding experiments for the rat brain gamma-aminobutyric acid (GABA) receptor, for which they could ultimately be used as irreversible affinity or photoaffinity probes. The aromatic heterocyclic series studied were 2-aminoimidazole, 2-aminothiazole, and 4-aminopyridine N-oxide. The derived diazonium salts are unstable compounds at neutral pH unless they are able to be deprotonated to the corresponding diazo form. As such, the 2-diazoimidazole-4(5)-acetic acid (3b) is stable in neutral medium and recognizes the GABA receptor (IC50 = 70 microM). The homocyclic aromatic diazonium salts showed sufficient stability to be tested in binding experiments. The diazonium salts derived from m-sulfanilic acid and 8-sulfonaphthylamine were the most interesting (10b, IC50 = 10 microM; 15b, IC50 less than 100 microM). In this series, the compounds that deprotonate at neutral pH (hydroxybenzenediazonium derivatives 12b-14b) showed increased chemical stability but decreased affinity for the GABA receptor. This difference between the diazoimidazole and the diazohydroxybenzene series is attributed to a different charge distribution between the two series. The ligands 3b, 10b, and 15b can be used as potential irreversible probes for the GABA receptor.

Affinity Labels↗
PubMedDate not supplied

The use of 4,4'-biphenylbisdiazonium fluoroborate as a coupling agent for passive haemolysis tests.

The possibility of use a stable diazonium compound, to replace bisdiazotized benzidin (BDB) for conjugating antigens to red blood cells was investigated. Five different batches of 4,4'-biphenylbisdiazonium fluoroborate (BDF) were prepared and tested in conjugation experiments. The sensitivity to specific lysis of red cells coated with different antigens (EG cells) was assayed by both direct and indirect passive haemolysis tests. Optimal conditions for the preparation of EG cells with different protein antigens were established. With the exception of the concentration of the bifunctional reagent, these conditions were similar to those previously reported for BDB. The antibody content of different anti-protein sera could be determined, with a 10 % error, by using EG cells prepared under optimal conditions in indirect passive haemolysis tests. The amount of antibody detected by this method varied from 7 to 12 ng N Ab/ml, depending upon the nature of the antigen fixed to red cell. The content of BSA in dilute solutions could be estimated by the specific inhibition of the indirect passive haemolysis tests. Testing different samples of BDF maintained at different conditions showed that the compound could be kept at room temperature, during the least four years, without appreciable loss of the conjugating properties, provided it was kept in the dry state and in the dark.

Animals↗
PubMed1989

Formation of direct-acting genotoxic substances in nitrosated smoked fish and meat products: identification of simple phenolic precursors and phenyldiazonium ions as reactive products.

Epidemiological studies have associated the consumption of smoked fish and meat products with an increased risk of stomach cancer. Therefore, the reaction of such smoked foods with nitrite under acidic conditions was investigated and was shown to produce potent direct-acting genotoxic substances as detected by the SOS Chromotest. Similar genotoxic activity was observed in nitrosated samples of wood-smoke condensates. Simple phenolic compounds such as phenol, 3-methoxycatechol, catechol and vanillin were identified as the precursors of the genotoxic substances. These phenolic compounds also exhibited direct-acting genotoxicity after nitrosation. The major genotoxic substances formed after nitrosation of phenol were isolated and identified as 4- and 2-hydroxyphenyldiazonium ions. Nitrosation of various wood-smoke condensates was found to generate the same type of diazonium compounds, which in part account for the genotoxicity of nitrosated smoked foods.

Animals↗
PubMed1978

Detection of estrogen-like compounds by thin-layer chromatography.

There are different national food regulations concerning the use of hormoneactive substances in the breeding of domestic animals that serve as human food. This situation requires specific and sensitive methods for the detection of any residues in food. The hormones used in practice can be determined with improved sensitivity by coupling to the diazonium compound Fast Dark Blue R Salt. After thin-layer chromatography on high-performance thin-layer chromatographic plates with two different solvent mixtures, zeranol, estradiol, estriol and estrone are analysed as azo dyestuffs. The detection limit of these hormones is below 10 ng.

Chromatography, Thin Layer↗
PubMed1987

Covalent binding of 4-carbamoylbenzenediazonium chloride to deoxyguanine bases of DNA resulting in apparent irreversible inhibition of poly(adenosine diphosphoribose) polymerase at the nicotinamide binding site.

The poly(adenosine diphosphoribose) polymerase activity of isolated liver nuclei was inhibited by 4-carbamoylbenzenediazonium chloride, referred to as 4-diazoniobenzamide, an effect that was dependent on the time of incubation and the concentration of the diazonium compound, with inhibition following first-order kinetics. The inhibition was not reversed by reisolation of nuclei and centrifugal washing, whereas the inhibition by benzamide or 4-aminobenzamide was completely reversible under these conditions. Simultaneous incubation of 4-diazoniobenzamide with benzamide prevented enzyme inhibition. The 4-diazoniobenzoic acid analogue was not inhibitory. The mechanism of action of 4-diazoniobenzamide was traced to a specific covalent binding to dGMP of DNA to form N2-[(4-carbamoylphenyl)azo]-2'-deoxyguanosine 5'-monophosphate. Coenzymic DNA, by tight association with the polymerase protein, fixes the -C(O)NH2 moiety of the adduct at the nicotinamide-binding site of the enzyme.

Animals↗
PubMed1990

Occupational asthma and specific IgE to a diazonium salt intermediate used in the polymer industry.

This study describes sensitization to a diazonium salt intermediate, diazonium tetrafluoroborate (DTFB), produced during the manufacture of a fluorine polymer precursor. Most of the workers exposed to DTFB powder complained of respiratory and mucosal irritation. However, some of these individuals had symptoms typical of occupational asthma. Clinical and immunologic studies, including bronchial provocation testing and specific IgE measurements, were performed on two individuals with asthmatic symptoms associated with exposure to DTFB. These studies confirmed a diagnosis of occupational asthma. In an investigation of 43 other exposed workers in two separate factories handling the diazonium compound, specific IgE antibodies to DTFB-human serum albumin conjugate were found in 20% of individuals. There was a good correlation between specific IgE and exposure-related respiratory symptoms, which suggests an IgE-mediated pathogenesis. DTFB-human serum albumin conjugates were characterized by electrophoretic techniques, and it was found that conjugates prepared at pH 10 elicited optimum IgE binding in RAST. In vitro cross-linking of albumin by DTFB was demonstrated but had no effect on RAST binding. Our findings on the effect of pH and polymerization on IgE binding support proposed mechanisms for in vivo conjugation and provide information on the antigenic determinants important in IgE recognition of hapten-carrier protein conjugates.

Antibody Formation↗
PubMed1979

Reaction electrophoresis.

The differential mobilities of compounds in an electric field are important analytical criteria and we can use them to bring electrophoretically pure components of a mixture medium on which they are separated. To this end, the compound undergoing reaction are brought into positions on the carrier to assure optimal contact between selected fractions, within a predetermined domain of time and distance. The appearance of a product defines their reactivities, and the product's continued migration on the same carrier can provide the first key to its identity as is demonstrated and discussed. The method is called reaction electrophoresis and it will be of particular use in studies with labile components. It is illustrated here with the coupling reaction of the sodium salt of 1,4-naphthol sulfonic acid and tetrazotized o-dianisidine.

Azo Compounds↗
PubMed1988

(Z,Z)-1,1'-(1,6-hexanediyl)bis(2-phenyldiazene) 2,2'-dioxide: a bis(azoxy) compound.

C18H22N4O2, Mr = 326.40, orthorhombic, Pbca, a = 19.475 (10), b = 10.435 (20), c = 8.762 (20) A, V = 1780.6 A3, Z = 4, Dx = 1.22 g cm-3, lambda(Mo K alpha) = 0.7107 A, mu = 0.76 cm-1, F(000) = 696, room temperature, 1564 reflections averaged from two octants, R = 0.044, wR = 0.050 for 669 observed reflections with I greater than sigma(I). The molecule has inversion symmetry and is nearly planar. The azoxy group is trans-substituted. Molecular packing is in herringbone-type layers.

Azo Compounds↗
PubMedDate not supplied

Cancer induction in mice by 4-hydroxybenzenediazonium sulfate of the Agaricus xanthodermus mushroom.

4-Hydroxybenzenediazonium sulfate (HBD) was administered to Swiss mice by subcutaneous injection at weekly intervals of two or 36 times at 10 or 2 micrograms per gram body weight, respectively. The HBD given 36 times induced tumors of the subcutis in 22% of females and in 22% of males. The corresponding tumor incidences in the untreated controls were 2% in females and 8% in males. Histopathologically, the neoplasms were classified as fibromas, fibrosarcomas, myxosarcomas and rhabdomyosarcomas. The HBD given two times was, however, without tumor-inducing effect. HBD is an ingredient of the Agaricus xanthodermus, a non-cultivable unedible mushroom, which is closely related to the mushroom of commerce Agaricus bisporus. HBD is now the third compound of the diazonium class to exhibit carcinogenic activity.

Agaricus↗
PubMed1978

Investigation of the transverse topology of the microsomal membrane using combinations of proteases and the non-penetrating reagent diazobenzene sulfonate.

Intact microsomal vesicles from rat liver were subjected to combined treatment with trypsin and an unspecific protease and were also examined after reaction with the chemical probe p-diazobenzene sulfonate. In addition, the latency of various enzymes in intact microsomal vesicles has been investigated. All microsomal electron transport enzymes studied, i.e. NADH-ferricyanide and cytochrome c reductases, cytochrome b5, NADPH-cytochrome c reductase and cytochrome P-450, were either solubilized or inactivated by one or both treatments. The experimental data indicate that UDPglucuronyl-transferase is also localized at the outer surface of microsomes. In contrast, a number of hydrolytic enzymes are apparently located inside the permeability barrier of the membrane and presumably at the inner surface. Under conditions where the levels of electron transport enzyme activities or amounts are changed, such as in newborn rats and rats treated with phenobarbital or methylcholanthrene, the intramembranous position of these enzymes is the same as in control adult rats. This indicates that the enzyme molecules are not relocated after their insertion into the membrane.

Animals↗
PubMed1976

[Influence of diazan on the mitotic cycle of leukemia L1210 cells].

By means of a autoradiographic method the effect of diazane - a new antitumor substance from the diasoketones class, on the mitotic cycle of leucimia L 1210 has been studied. Diazane in single administration was found to inhibit the development of leucemic process during 2 days. This substance reduces considerably the DNA synthesis intensity in cells, due to that the mitotic activity of cells is markedly reduced. It was demonstrated that diazane during 8 hours blocked the transfer of cells from a presynthetic stage into the DNA synthesis phase. But this substance does not influence the transfer of cells from the premitotic period into mitosis. The substance delayes continuously (during 36 hours) the division of cells being in a phase of the DNA synthesis during its injection. In later terms although multiplication of these cells would be restored, but its intensity is decreased.

Animals↗
PubMed1979

Extracellular labeling of growing secreted polypeptide chains in Bacillus subtilis with diazoiodosulfanilic acid.

Studies of the mechanism of protein secretion in a Gram-positive bacterium, Bacillus subtilis, yielded results very similar to those previously obtained with a Gram-negative organism: nascent chains protruding from protoplasts could be labeled extracellularly; the labeled chains could be recovered on polysomes isolated from the membrane--polysome fraction; they could be released by puromycin, low Mg2+, or chain completion; the completed chains include a known secreted protein (alpha-amylase); and their ribosomes appear to be attached to membrane solely by their nascent chains. The reagent used for extracellular labeling, [1252]diazoiodosulfanilic acid, yielded severalfold more specific labeling of the nascent chains (7--10% of the total cellular labeling and one-fourth to one-third of that of the membrane--polysome fraction) than was obtained earlier with another nonpenetrating reagent.

Amylases↗