Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of erythromycin, chloramphenicol, cycloheximide, pyrimethamine, chromate, cadmium, lead, nickel, 4-nitro-quinoline-1-oxide and thioacetamide on yeast and human cells were studied. Inhibition of the synthesis of mitochondrial proteins resulted in the loss of cytochromes as well as in morphological changes in the cellular membranes and mitotic arrest. The data are discussed.
Mol Cell Biochem 1977 Feb 04
PMID:Mitochondrial biogenesis: inhibitors of mitochondrial protein synthesis. 40 20

Sodium/copper chlorophyllin (CHL) is a water-soluble derivative of chlorophyll that exhibits antimutagenic activity in several short-term genotoxicity assays and inhibits carcinogen-DNA binding in vivo. The effect of CHL pretreatment on the excretion of mutagens in the urine and feces of male Sprague-Dawley rats has been studied using the Salmonella mutagenicity assay. Animals were given 1 percent CHL in the drinking water for 2 days before administering a single dose of 2-amino-3-methylimidazo-[4,5-f]quinoline (IQ) by oral gavage. Rats pretreated with CHL had higher levels of mutagens in the urine and feces compared with animals given IQ alone; 48 hr after IQ administration, the total mutagenic dose excreted was < 4% in controls vs. 18% in rats given CHL. Mutagenicity required the presence of an activation system, was unaffected by treatment with beta-glucuronidase or arylsulfatase, and in both the urine and feces was accounted for by increased elimination of unmetabolized parent compound. The results support the view that CHL may operate in vivo as a "desmutagen" or interceptor molecule, interacting with IQ in the gut and tissues, and reducing carcinogen bioavailability.
Environ Mol Mutagen 1992
PMID:Chlorophyllin-enhanced excretion of urinary and fecal mutagens in rats given 2-amino-3-methylimidazo[4,5-f]quinoline. 139 10

Incubation of rat brain synaptosomes and mitochondria with LPO inducers (Fe2+ and ascorbate) was accompanied by a decrease of deamination of serotonin (substrate of MAO-A) in mitochondria, but not in synaptosomes, with simultaneous stimulation of GABA and GLCA deamination, apparently owing to modification of catalytic properties of brain membrane-bound MAO. Oxidation of PEA (substrate of MAO-B) was insignificantly altered in both fractions. Reactions of deamination of serotonin, GABA, and GLCA (but not PEA), were highly sensitive to a selective inhibitor of MAO-A pyrazidol (pyrlindole). Isoniazid and hydrazides of quinoline carbonic acids (inhibitors of both modified MAO and copper-containing amine oxidases) strongly inhibited deamination of GABA and GLCA. During epileptiformic seizures in rats, genetically selected for high incidence of audiogenic epilepsia, stimulation in brain synaptosomes and mitochondria of LPO was observed. This was accompanied by a marked decrease in serotonin and PEA deamination, with a simultaneous increase in GABA and GLCA deamination in both fractions. The data obtained suggest that appearance of GABA-deaminating activity owing to modification of catalytic properties of MAO, might be an essential pathogenetic component in the development of epileptic seizures.
Mol Chem Neuropathol
PMID:The role of lipid peroxidation in the possible involvement of membrane-bound monoamine oxidases in gamma-aminobutyric acid and glucosamine deamination in rat brain. Focus on chemical pathogenesis of experimental audiogenic epilepsy. 152 Apr 3

An 18-kDa leukocyte membrane protein, termed 5-lipoxygenase-activating protein (FLAP), has recently been shown to be the target of two structurally distinct classes of leukotriene biosynthesis inhibitors. These classes of inhibitors are based on indole and quinoline structures and are represented by MK-886 and L-674,573, respectively. A novel class of hybrid structure based on the indole and quinoline classes of inhibitors, termed quindoles, has recently been developed. These compounds, exemplified by L-689,037, are potent inhibitors of leukotriene biosynthesis, both in vitro and in vivo. In the present study, we have developed and characterized a potent radioiodinated photoaffinity analogue of L-689,037, termed [125I]L-691,678. This compound was used in immunoprecipitation studies with FLAP antisera to show that the quindole series of leukotriene biosynthesis inhibitors interact directly with FLAP. In addition, we show that MK-886, L-674,573, and L-689,037 specifically compete, in a concentration-dependent manner, with both [125I]L-691,678 and [125I]L-669,083, a photoaffinity analogue of MK-886, for binding to FLAP. These results suggest that these three classes of leukotriene biosynthesis inhibitors share a common binding site on FLAP, providing further evidence that FLAP represents a suitable target for structurally diverse classes of leukotriene biosynthesis inhibitors.
Mol Pharmacol 1992 Feb
PMID:5-Lipoxygenase-activating protein is the target of a novel hybrid of two classes of leukotriene biosynthesis inhibitors. 153 7

Previous studies have shown that the rat liver carcinogen quinoline is essentially nongenotoxic to the rat liver in vivo. Those studies also established it as a potent mitogen to rat liver. The present experiments have established quinoline as a mitogen to the mouse liver, a tissue in which it is also reported to be carcinogenic. In contrast, quinoline is reported to be noncarcinogenic to the guinea pig liver, and the present data establish it to be essentially nonmitogenic to the guinea pig liver. It is concluded that the mitogenicity of quinoline correlates better with its hepatocarcinogenic properties than does its genotoxicity in vivo.
Environ Mol Mutagen 1992
PMID:Mitogenic activity of quinoline to the rat, mouse, and guinea pig liver: empirical correlations with hepatic carcinogenicity. 163 82

With the aim of obtaining new inhibitors of topoisomerases, we have evaluated various heterocyclic quinone derivatives for their ability to induce topoisomerase I (Topo I)- or Topo II-associated DNA breaks, using P388 cell nuclear extract. Several compounds belonging to the indolo[3,2-c]quinoline-1,4-dione series have been shown to possess DNA-cleavage activity. Further analysis using purified Topo I and II preparations has indicated that the members of the series stimulate cleavable complex formation of both Topo I and II. 3-Methoxy-11H-pyrido[3',4':4,5]pyrrolo[3,2-c] quinoline-1,4-dione (AzalQD), one of the most active members of the series, stimulates cleavable complex formation and inhibits the catalytic activities of both eukaryotic Topo I and II, with, however, less potency than camptothecin and etoposide. Topo I cleavage site patterns for AzalQD and camptothecin were found to be nearly identical, with, however, some differences in cleavage site intensities. Use of filter binding assays also indicates that AzalQD is at least 10 times more potent against Topo I than against Topo II. Structure-activity relationships of indoloquinolinedione derivatives have been established and have shown that Topo I and II inhibitions are strongly linked, with a dose-selective preference towards Topo I. AzalQD does not display detectable DNA-unwinding properties. AzalQD induces a preferential cytotoxicity for the yeast strain JN2-134 bearing the human top1 gene under the control fo the GAL1 promoter, indicating that Topo I inhibition is responsible for the yeast cytotoxicity. These data indicate that AzalQD and its structural analogs represent a new distinct class of eukaryotic Topo I and II inhibitors.
Mol Pharmacol 1991 Nov
PMID:Inhibition of eukaryotic DNA topoisomerase I and II activities by indoloquinolinedione derivatives. 165 5

An indole class of leukotriene synthesis inhibitors, exemplified by MK-886, which does not directly inhibit 5-lipoxygenase, has been shown to bind to an 18-kDa leukocyte membrane protein and to inhibit 5-lipoxygenase membrane translocation. It was demonstrated that the 18-kDa protein is necessary for the cellular activation of leukotriene synthesis and was named 5-lipoxygenase-activating protein (FLAP). We describe here a class of leukotriene synthesis inhibitors based on a quinoline structure, which is structurally distinct from MK-886. However, similar to MK-886, several quinolines are potent inhibitors of cellular leukotriene synthesis but are poor inhibitors of soluble 5-lipoxygenase. To determine whether FLAP is the protein target of leukotriene synthesis inhibitors of the quinoline class, we investigated the ability of these compounds to inhibit photoaffinity labeling of FLAP and to elute FLAP from indole affinity gels. The abilities of the quinoline inhibitors to interact with FLAP correlated well with their abilities to inhibit leukotriene synthesis in human polymorphonuclear leukocytes. L-674,573, a potent quinoline leukotriene synthesis inhibitor, inhibited indole photoaffinity labeling of FLAP in a concentration-dependent manner. In addition, L-674,573 selectively eluted FLAP from indole affinity gels, in contrast to L-671,480, a quinoline that was inactive as an inhibitor of leukotriene synthesis. When human leukocyte membranes were labeled with the indole photoaffinity probe [125I]L-669,083 and immunoprecipitated with a FLAP antibody, the labeling of FLAP was inhibited by L-674,573 but not by L-671,480. These results suggest a direct binding site for the quinoline leukotriene synthesis inhibitors on FLAP and provide further evidence for the essential role of FLAP in cellular leukotriene synthesis.
Mol Pharmacol 1991 Jul
PMID:5-Lipoxygenase-activating protein is the target of a quinoline class of leukotriene synthesis inhibitors. 185 37

Ascorbic acid (VC) deficiency resulted in a decrease in the activities of aminopyrine N-demethylase, aniline hydroxylase, and p-nitroanisole O-demethylase and in the content of cytochrome P-450, as spectrally determined, whereas it caused an increase in the activities of 6 beta-hydroxylases for testosterone and progesterone in liver microsomes of guinea pigs. Western blot analysis of liver microsomes with antibodies to rat P-448-H (P-4501A2), P-450j (P-450IIE), P-450 PB-1 (P-450IIIA), and P-450b (P-450IIB1) showed that VC deficiency decreased the amount of cytochrome P-450 immunochemically related to P-450IA2 and P-450IIE but did not change the amount of the form that was cross-reactive with antibodies to P-450IIB1 and tended to slightly increase (not statistically significantly) the amount of the form of the cytochrome immunochemically related to P-450IIIA. The larger decrease by VC deficiency in the amount of cytochrome P-450 that was cross-reactive to the rat P-450IA2 resulted in a lower capacity of liver microsomes to activate promutagens, such as 2-amino-3-methyl-imidazo(4,5-f)quinoline and aflatoxin B1. These results indicate that VC deficiency in guinea pigs differentially affects the content of individual forms of cytochrome P-450.
Mol Pharmacol 1991 Apr
PMID:Ascorbic acid deficiency decreases specific forms of cytochrome P-450 in liver microsomes of guinea pigs. 190 38

We transduced mouse cytochrome P4501A2 DNA into NIH 3T3 cells by retrovirus-mediated gene transfer. The capacity of the transduced cytochrome P4501A2 for metabolic activation and DNA-carcinogen adduct formation of aromatic amine carcinogens was investigated. Clones of NIH 3T3 cells that constitutively express cytochrome P4501A2 and controls were exposed to a prototype food-derived carcinogenic heterocyclic amine, 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), and an aromatic amine, 2-acetylaminofluorene (AAF), and their genomic DNAs were analyzed for adducts by 32P-postlabeling assays. Kinetic analysis of DNA-carcinogen adducts indicated that adduct formation was dependent on the level of the enzyme, the dose of carcinogen, and the duration of exposure. Addition of 7,8-benzoflavone, an inhibitor of P4501A2, blocked both the enzyme activity and DNA-adduct formation, indicating the specific role of P4501A2 in metabolic activation and adduct formation. Three specific IQ-DNA adducts were detected in cells expressing P4501A2. Fingerprints of the in situ DNA adducts were similar to those of the in vivo adducts in rodent hepatic DNA after the administration of IQ. A single AAF-DNA adduct was observed in cells exposed to AAF, but other minor adducts were also detected in vivo. These results show that cells expressing constitutive levels of single cytochrome P450s provide an excellent in situ model system for analyzing the catalytic specificity, metabolic activation, and genotoxicity of putative toxic, mutagenic, and carcinogenic substances.
Mol Carcinog 1991
PMID:Cytochrome P4501A2 constitutively expressed from transduced DNA mediates metabolic activation and DNA-adduct formation of aromatic amine carcinogens in NIH 3T3 cells. 191 Apr 84

Cytochrome P-450 (P-450) 2A6 was purified by chromatography of human liver microsomes. The final preparation was electrophoretically homogeneous and contained 16 nmol of P-450/mg of protein. The amino-terminal amino acid sequence of the protein (first 13 residues) matched that of the reported cDNA exactly. The UV-visible spectrum indicated that the isolated hemoprotein was in the low-spin form. The protein was recognized by rabbit antibodies raised against rat P-450 2A1, and a rabbit antiserum against the P-450 2A6 preparation was also prepared. With these antibodies, it was estimated that P-450 2A6 accounted for a maximum of 1% of the total P-450 present in the human liver microsomes; the level varied greater than 100-fold among the 20 samples examined. Purified P-450 2A6 catalyzed coumarin 7-hydroxylation and 7-ethoxycoumarin O-deethylation at rates similar to those measured in the human liver sample used to prepare P-450 2A6, and these two microsomal activities were strongly inhibited by the antibodies. The purified P-450 2A6 enzyme also catalyzed low levels of 4,4'-methylene-bis(2-chloroaniline) (MOCA) N-oxidation and activation of aflatoxin B1, 6-aminochrysene, 2-amino-3-methylimidazo[4,5-f]quinoline, and 2-amino-3,5-dimethylimidazo [4,5-f]quinoline to genotoxic products; the antibody inhibited the activity of purified P-450 2A6 towards aflatoxin B1 and 6-aminochrysene but did not inhibit these reactions in human liver microsomes (MOCA N-oxidation was inhibited approximately 20%). Human P-450 2A6 did not catalyze testosterone 7 alpha-hydroxylation, a characteristic activity of the related rat P-450 2A1 protein. These results emphasize the need to characterize individual P-450 enzymes in order to understand their functions in the context of more complex systems.
Mol Pharmacol 1991 Nov
PMID:Purification and characterization of human liver microsomal cytochrome P-450 2A6. 194 38


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