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At least 19 recordsLinked to original sources
PubMed1979

A resonance Raman and electronic absorption probe of membrane energization. Quinaldine red in cells of Streptococcus faecalis.

Resonance Raman and electronic absorption spectra were used to show that the state of an amphiphilic cation, relative to dilute aqueous solution, changes when it is accumulated by cells of Streptococcus faecalis when they are energized. The general characteristics of the cation employed, quinaldine red, closely paralleled those of other amphiphilic cations which have been used to measure membrane potential. A major aspect of the change is that in sodium-loaded cells, essentially all of the quinaldine red accumulated as the result of energization forms a strong bond with an anionic group. This binding is similar to that which occurs for the basal level of quinaldine red taken up in nonenergized cells. Ionic binding was detected using resonance Raman spectroscopy through shifts associated with a N+ parallel C--C parallel C stretching vibration to lower frequency on uptake. Another aspect of the change in state is that the cell-localized probe cation can aggregate while ionically bonded in a card pack fashion, the transition dipoles being parallel. A combination of resonance Raman and electronic absorption spectroscopy was used to characterize this aggregation. The aggregates were estimated to contain at least five quinaldine red cations at or near van der Waals contact, and the presence of other molecules, such as phospholipids, could not be excluded. Aggregation effects are complex depending on the ratio of cells to probe cation, and on energization. The site of binding is suggested to be the lipid bilayer region of the plasma membrane on the basis of experiments with liposomes and other model systems. In addition, some quinaldine red may be present in the cytoplasm in an aggregated, ionically bound form. The change in state on uptake following energization seems to be associated with a membrane potential, similar spectral and uptake effects being produced by an artificially generated membrane potential in cells and liposomes. The results show that membrane potential cannot be computed in a simple manner from the distribution of quinaldine red between cells and medium, assuming that the thermodynamic activity coefficient of cell-localized material is identical with that in dilute aqueous solution. However, uptake as well as subsequent ionic binding of quinaldine red seems to be related to potential in an as yet undefined manner.

Cell Membrane↗
PubMed1996

Quinaldine 4-oxidase from Arthrobacter sp. Rü61a, a versatile procaryotic molybdenum-containing hydroxylase active towards N-containing heterocyclic compounds and aromatic aldehydes.

Quinaldine 4-oxidase from Arthrobacter sp. Rü61a, an inducible molybdenum-containing hydroxylase, was purified to homogeneity by an optimized five-step procedure. Molecular oxygen is proposed as physiological electron acceptor. Electrons are also transferred to artificial electron acceptors with E'o > -8 mV. The molybdo-iron/sulfur flavoprotein regiospecifically attacks its N-heterocyclic substrates: isoquinoline and phthalazine are hydroxylated adjacent to the N-heteroatom at Cl, whereas quinaldine, quinoline, cinnoline and quinazoline are hydroxylated at C4. Additionally, the aromatic aldehydes benzaldehyde, salicylaldehyde, vanillin and cinnamaldehyde are oxidized to the corresponding carboxylic acids, whereas short-chain aliphatic aldehydes are not. Quinaldine 4-oxidase is compared to the two molybdenum-containing hydroxylases quinoline 2-oxidoreductase from Pseudomonas putida 86 [Tshisuaka, B., Kappl, R., Hüttermann, J. & Lingens, F. (1993) Biochemistry 32, 12928-12934] and isoquinoline 1-oxidoreductase from Pseudomonas diminuta 7 [Lehmann, M., Tshisuaka, B., Fetzner, S., Röger, P. & Lingens, F. (1994) J. Biol. Chem. 269, 11254-11260] with respect to the substrates converted and the electron-acceptor specificities. These dehydrogenases hydroxylate their N-heterocyclic substrates exclusively adjacent to the heteroatom. Whereas the aldehydes tested are scarcely oxidized by quinoline 2-oxidoreductase, isoquinoline 1-oxidoreductase catalyzes the oxidation of the aromatic aldehydes, although being progressively inhibited. Neither quinoline 2-oxidoreductase nor isoquinoline 1-oxidoreductase transfer electrons to oxygen. Otherwise, the spectrum of electron acceptors used by quinoline 2-oxidoreductase and quinaldine 4-oxidase is identical. However, isoquinoline 1-oxidoreductase differs in its electron-acceptor specificity. Quinaldine 4-oxidase is unusual in its substrate and electron-acceptor specificity. This enzyme is able to function as oxidase or dehydrogenase, it oxidizes aldehydes, and it catalyzes the nucleophilic attack of N-containing heterocyclic compounds at two varying positions depending on the substrate.

Aldehydes↗
PubMed1977

The formation of 2-hydroxymethylquinoline and quinaldine in greyhound urine.

2-Hydroxymethylquinoline and quinaldine are found in nonfresh greyhound urine as putrefactive bases. Their production as a function of time was investigated. This is affected by preservatives or refrigeration. 2-Hydroxymethylquinoline forms in greyhound urine, if non-preserved, in three or four days at room temperature while quinaldine takes as much as 10 days longer to form. Production of 2-hydroxymethylquinoline or quinaldine is not arrested but merely retarded by preservation or refrigeration. Sodium fluoride is one of the more effective preservatives. A method for the measurement of quinaldine and 2-hydroxymethylquinoline using gas chromatography is described. The columns used are Carbowax 6000 + potassium hydroxide on Chromosorb G and SE-30 on Chromosorb W.

Animals↗
PubMed1997

Comparative EPR and redox studies of three prokaryotic enzymes of the xanthine oxidase family: quinoline 2-oxidoreductase, quinaldine 4-oxidase, and isoquinoline 1-oxidoreductase.

For three prokaryotic enzymes of the xanthine oxidase family, namely quinoline 2-oxidoreductase, quinaldine 4-oxidase, and isoquinoline 1-oxidoreductase, the electron transfer centers were investigated by electron paramagnetic resonance. The enzymes are containing a molybdenum-molybdopterin cytosine dinucleotide cofactor, two distinct [2Fe-2S] clusters and, apart from isoquinoline 1-oxidoreductase, a flavin adenine dinucleotide. The latter cofactor yields two different organic radical signals in quinoline 2-oxidoreductase and quinaldine 4-oxidase, typical for the neutral and anionic form, respectively. A "rapid" Mo(V) species is present in all enzymes with small differences in magnetic parameters. From spectra simulation of 95Mo-substituted quinoline 2-oxidoreductase, a deviation of 25 degrees between the maximal g and 95Mo-hyperfine tensor component was derived. The very rapid Mo(V) species was detected in small amounts upon reduction with substrates in quinoline 2-oxidoreductase and quinaldine 4-oxidase, but showed a different kinetic behavior with considerable EPR intensities in isoquinoline 1-oxidoreductase. The FeSI and FeSII centers produced different signals in all three enzymes and, in case of isoquinoline 1-oxidoreductase, revealed a dipolar interaction, from which a maximum distance of 15 A between FeSI and FeSII was estimated. The midpoint potentials of the FeS centers were surprisingly different and determined for FeSI/FeSII with -155/-195 mV in quinoline 2-oxidoreductase, -250/-70 mV in quinaldine 4-oxidase, and +65/+10 mV in isoquinoline 1-oxidoreductase. The slopes of the fitting curves for the Nernst equation are indicative for nonideal behavior. Only in quinoline 2-oxidoreductase, an averaged midpoint potential of the molybdenum redox pairs of about -390 mV could be determined. Both of the other enzymes did not produce Mo(V) signals in redox titration experiments, probably because of direct reduction of Mo(VI) to Mo(IV) in the presence of dithionite.

Electron Spin Resonance Spectroscopy↗
PubMed1982

Hepatic microsomes from freshwater fish--II. Reduction of benzo(a)pyrene metabolism by the fish anesthetics quinaldine sulfate and tricaine.

1. A single in vivo exposure of brook trout (Salvelinus fontinalis) to a 30.0 mg/l solution of quinaldine sulfate or a 112.5 mg/l solution of tricaine for 5 min significantly reduced the in vitro hydroxylation of benzo(a)pyrene. 2. Since quinaldine sulfate and tricaine formed type I and II binding spectra, respectively, with brook trout hepatic cytochrome P-450, these chemicals probably reduced benzo(a)pyrene hydroxylase enzyme activity by altering the form(s) of cytochrome P-450 responsible for this activity. 3. Hepatic microsomal cytochrome P-450 from brook trout treated with tricaine for 5 min and then placed into fresh water for 24 hr had returned to control levels. 4. Caution should be exercised in the use of quinaldine sulfate or tricaine to anesthetize fish prior to analysis of hepatic microsomal mixed function oxidases.

Aminobenzoates↗
PubMed1990

Microbial metabolism of quinoline and related compounds. VI. Degradation of quinaldine by Arthrobacter sp.

Quinaldine catabolism was investigated with the bacterial strain Arthrobacter sp., which is able to grow aerobically in a mineral salt medium with quinaldine as sole source of carbon, nitrogen and energy. The following degradation products of quinaldine were isolated from the culture fluid and identified: 1H-4-oxoquinaldine, N-acetylisatic acid, N-acetylanthranilic acid, anthranilic acid, 3-hydroxy-N-acetylanthranilic acid and catechol. 3-Hydroxy-N-acetylanthranilic acid was not further metabolized by this organism. A degradation pathway is proposed.

Arthrobacter↗
PubMed1993

Microbial metabolism of quinoline and related compounds. XVI. Quinaldine oxidoreductase from Arthrobacter spec. Rü 61a: a molybdenum-containing enzyme catalysing the hydroxylation at C-4 of the heterocycle.

Quinaldine oxidoreductase from Arthrobacter spec. Rü 61a converts quinaldine to 1H-4-oxoquinaldine. The enzyme was purified 70-fold to apparent homogeneity in a 5-step procedure with a recovery of 4%. The molecular mass of the native enzyme was calculated to be 340,000 Da by gel filtration. SDS-polyacrylamide gel electrophoresis of the enzyme revealed 3 protein bands corresponding to 82,000 Da, 35,000 Da and 22,000 Da. The enzyme contained 1.6 atoms of molybdenum, 8 atoms of iron, 8 atoms of acid labile sulfur, 2 molecules of FAD and as part of the molybdenum cofactor, molybdopterin cytosine dinucleotide. Due to the composition of the cofactors the quinaldine oxidoreductase belongs to the class of molybdo-iron/sulfur-flavoproteins. Cyanide, arsenite and 4-hydroxymercuribenzoate were effective inhibitors whereas the enzyme was not affected by methanol.

Amino Acid Sequence↗
PubMed1994

A simple and rapid fluorometric determination method of alpha 1-acid glycoprotein in serum using quinaldine red.

We examined different fluorescent probes suitable for fluorometric determination of alpha 1-acid glycoprotein (AGP) in serum. Quinaldine red (QR) was shown to bind strongly and selectively to AGP. Taking advantage of the enhanced fluorescence of QR in the presence of AGP, we developed a direct method for the determination of serum AGP without removal of other serum proteins such as albumin. AGP concentrations in serum of healthy volunteers and patients correlated well with results from the conventional single radial immunodiffusion (SRID) method (r = 0.93, slope = 1). The newly developed method is faster and has a larger analytical concentration range than the SRID method. This method can also be used to determine AGP in serum of experimental animals, and it can serve to monitor AGP serum concentrations for pharmacokinetic evaluation of basic drugs.

Adult↗
PubMed1993

Evaluation of quinaldine red as a fluorescent probe for studies of drug-alpha 1-acid glycoprotein interaction.

We attempted to develop a fluorescent probe superior to conventional ones (8-anilino-1-naphthalenesulfonate and auramine O) for use in the study of drug-binding sites on alpha 1-acid glycoprotein (AGP). It was found that quinaldine red (QR) strongly bound to AGP and had an enhanced fluorescence in the presence of AGP at a longer wavelength, although QR was rarely fluorescent in an aqueous or albumin solution. The binding parameters of QR to AGP were K: 1.3 x 10(6) M-1 and n: 0.9, using the fluorometric titration method. The fluorescence of QR in the AGP solution, however, was markedly quenched in the presence of basic drugs, indicating that these drugs competitively displaced QR from its binding site; the results were in good agreement with those in the literature. The good relationship between binding affinities and partition coefficients suggested that hydrophobic forces were involved in the binding of basic drugs to AGP. Moreover, the polarity of the binding site of AGP estimated from the relationship between the emission maximum of QR and Z values was 70, which corresponds to the same Z value of acetonitrile. These results distinguish QR from other conventional AGP probes as a better fluorescent probe by which to understand drug-AGP interaction and the characterization of binding sites on AGP in more detail.

Binding, Competitive↗
PubMed1977

Synthsis and antitumor properties of bis(quinaldine) derivatives.

A series of 7-nitro- and amino-N,'-bis(4-quinaldinyl)-alpha, omega-diaminoalkanes related to the 6-amino derivative 1 was synthesized and tested in the mouse P-388 lymphocytic leukemia screen. There of the 7-nitro derivatives (12, 14, and 15) were found to have moderate activity (T/C 140-150%), while other nitro derivatives (11 and 13) were devoid of any antitumor properties. All five 7-amino compounds (2-6) were moderately to strongly active (T/C 134-196%). In addition, binding of amino derivatives 2-6 to DNA was examined by their ability to (1) stabilize DNA to thermal denaturation and (2) inhibit the DNA-dependent RNA polymerase reaction in vitro. Tm data suggest that these compounds bind to DNA and are strong inhibitors of the polymerase reaction (I50 = 6-9 X 10(-6) M).

Animals↗