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)

To explore the level of regulation of the expression of the major antioxidant enzymes in response to hyperoxia, we exposed human umbilical vein endothelial cells to 95% O2 for 3 and 5 days and measured (1) the steady-state mRNA levels, (2) the activities, and (3) the immunoreactive content of CuZn and Mn superoxide dismutases (SOD), catalase (CAT), and glutathione peroxidase (GP). We found that a 3-day exposure to 95% O2 caused (1) an increase in CuZnSOD mRNA (by 41%), CAT mRNA (by 26%), and GP mRNA (by 173%); (2) an increase in CuZnSOD activity (by 30%), a decrease in CAT activity (by 37%), and an increase in GP activity (by 60%); and (3) an increase in CuZnSOD immunodetectable protein (by 26%) and a loss in CAT immunoreactive protein (by 27%). After a 5-day exposure to 95% O2, there was (1) a 93% increase in CuZnSOD mRNA, a 71% increase in CAT mRNA, and a 127% increase in GP mRNA; (2) a 56% increase in CuZnSOD activity, a 70% decrease in CAT activity, and an 89% increase in GP activity; and (3) a 35% increase in CuZnSOD immunoreactive protein and a 55% loss in CAT immunoreactive protein. There was no change in the steady-state MnSOD mRNA level after 3 days in 95% O2, but a 100% increase was observed on day 5 of oxygen exposure. MnSOD activity was unchanged in cells exposed to hyperoxia for 3 and 5 days. These data suggest that, in human umbilical vein endothelial cells, the regulation of antioxidant enzymes expression in response to O2 is complex and exerted at different levels.
Am J Respir Cell Mol Biol 1992 Jan
PMID:Response of human endothelial cell antioxidant enzymes to hyperoxia. 172 89

Previous work has shown that the firefly (Photinus pyralis) luciferase contains a C-terminal peroxisomal targeting signal consisting of the tripeptide Ser-Lys-Leu. This report describes the microinjection of two proteins, (i) luciferase and (ii) albumin conjugated to a peptide ending in the sequence Ser-Lys-Leu, into mammalian cells grown in tissue culture. Following microinjection, incubation of the cells at 37 degrees C resulted in peroxisomal transport of these exogenous proteins into catalase-containing vesicles. The translocation was both time and temperature dependent. The transport could be inhibited by coinjection of synthetic peptides bearing various peroxisomal targeting signal motifs. These proteins could be transported into peroxisomes in normal human fibroblast cell lines but not in cell lines derived from patients with Zellweger syndrome. These results demonstrate that microinjection of peroxisomal proteins yields an authentic in vivo system with which to study peroxisomal transport. Furthermore, these results reveal that the process of peroxisomal transport does not involve irreversible modification of the protein, that artificial hybrid substrates can be transported and used as tools to study peroxisomal transport, and that the defect in Zellweger syndrome is indeed the inability to transport proteins containing the Ser-Lys-Leu targeting signal into the peroxisomal lumen.
Mol Cell Biol 1992 Feb
PMID:Transport of microinjected proteins into peroxisomes of mammalian cells: inability of Zellweger cell lines to import proteins with the SKL tripeptide peroxisomal targeting signal. 173 29

Expression of the myosin heavy-chain beta gene is controlled by multiple cis-acting regulatory elements in the 5' flanking region; two of these, referred to as A (-276 to -263) and B (-207 to -180), are essential for conferring muscle-specific activation on homologous and heterologous promoters. Here we report on the identification of nuclear protein factors that specifically bind to these two elements. By using the A element as a probe, as well as nuclear extracts from muscle cells, we found two protein-DNA complexes that displayed distinct bands in a gel mobility shift assay but had identical methylation interference patterns. One complex was present mainly in nuclear extracts from undifferentiated muscle and nonmuscle cells, whereas the other was observed mainly in nuclear extracts from differentiated muscle cells. Thus, the muscle-specific complex formation with the A element appears to be involved in determining tissue-specific expression. Furthermore, competition analysis demonstrated that the A-element-binding factors also bind to the muscle-CAT motif in the cardiac troponin T gene. By using the B element as a probe, we saw similar patterns of gel-shifted bands and methylation interference in nonmuscle and muscle nuclear extracts. In addition, both elements A and B were found to be necessary for tissue-specific expression, suggesting that the muscle-specific activation of the myosin heavy-chain beta gene may require interaction between a muscle-specific and a ubiquitous protein-DNA complex.
Mol Cell Biol 1992 Feb
PMID:Both muscle-specific and ubiquitous nuclear factors are required for muscle-specific expression of the myosin heavy-chain beta gene in cultured cells. 173 34

To clarify whether ischemic liver injury is due to ischemia itself or reperfusion, histopathological and functional changes in the liver were examined before and after liver ischemia in rats with porto-systemic collateral channels. Effects of oxygen-derived free radical scavengers or an inhibitor of platelet aggregation on development of ischemic liver injury were also examined. Liver ischemia was produced by ligation of the portal vein and hepatic artery at liver hilum for 1 hr. The primary lesion of ischemic liver injury was cloudy swelling of liver cells in the periportal and midzonal regions; it developed during ischemia. The cloudy swelling of liver cells induced uneven distribution of sinusoidal blood flow after reperfusion, and consequently individual liver cell necrosis and focal hepatocellular necrosis in the midzonal regions developed later. Elevation of cytoplasmic enzyme activities in the serum after reperfusion was due to leakage across the damaged plasma membrane of liver cells. The treatment with superoxide dismutase, catalase, or heparin had not altered the liver injury that was attributed to ischemia, biochemically and histologically. These results suggest that ischemic liver injury is due to liver cell damage developed during ischemia, and that the ischemic liver injury is not alleviated or prevented by superoxide dismutase, catalase, or heparin.
Exp Mol Pathol 1991 Dec
PMID:Mechanism of liver injury following ischemia. 174 14

Mediation by Ca2+ of TRH action on the PRL promoter was investigated by both additivity and pharmacological studies and by techniques that probe more gene-proximal events. TRH required the presence of Ca2+ in the medium for stimulation of transient expression in GH3 cells of a PRL-chloramphenicol acetyltransferase (PRL-CAT) construct containing proximal PRL promoter sequences [(-187)PRL-CAT]. Chronic 12-O-tetradecanoyl phorbol-13-acetate down-regulation of cellular protein kinase C did not block induction of expression of (-187)PRL-CAT by either Ca2+ or TRH. In studies with Ca2+ blockers, the Ca2+ flux inhibitors cobalt ion and nimodipine blocked induction of (-187)PRL-CAT expression by either Ca2+ or TRH. On the other hand, the Ca2+ immobilizers 1,2-bis(O-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid acetoxymethyltetraester and 8-(N,N-diethylamino)octyl 3,4,5-trimethoxybenzoate blocked induction of expression of this construct by Ca2+ but not by TRH, suggesting that TRH regulation of the PRL promoter may be dependent on Ca2+ fluxes but insensitive to Ca2+ immobilization. We have shown previously that the PRL promoter pit-1 binding site 1P is a TRH response element. In the present studies, Ca2+ regulation studies with 5'-deletion mutants of (-204)PRL-CAT showed that (-75)PRL-CAT, containing the single pit-1 binding site 1P, also contains a Ca2+ response element. The observation that two copies of a site 1P oligomer transferred a Ca2+ response to either of the two minimal constructs (-39)PRL-CAT or (-39)mouse metallothionein-CAT showed that site 1P is an independent Ca2+ response element. Analysis of site 1P mutants yielded a strong correlation between the ability to bind pit-1 and to transfer a Ca2+ response. In addition, coexpression of a mutant pit-1 possessing reduced trans-activational activity strongly inhibited TRH regulation of (-187)PRL-CAT and partially blocked Ca2+ regulation of this construct. We conclude that Ca2+ mediates TRH action on the PRL promoter, and that pit-1 represents a gene-proximal mediator in this signalling pathway.
Mol Endocrinol 1991 Oct
PMID:Mediation by calcium of thyrotropin--releasing hormone action on the prolactin promoter via transcription factor pit-1. 177 32

We have identified two different single nucleotide alterations in codon 686 (GAC; aspartic acid) in exon 4 of the human androgen receptor gene in three unrelated families with the complete form of androgen insensitivity. One mutation (G----C) results in an aspartic acid----histidine substitution (with 15-20% of wild-type androgen-binding capacity), whereas the other mutation (G----A) leads to an aspartic acid----asparagine substitution (with normal androgen-binding capacity, but a rapidly dissociating ligand-receptor complex). The mutations eliminate a Hinfl restriction site. Screening for the loss of the Hinfl site in both families with the Asp----Asn mutation resulted in the recognition of heterozygous carriers in successive generations of each. Both mutant androgen receptors were generated in vitro and transiently expressed in COS and HeLa cells. The receptor proteins produced had the same altered binding characteristics as those measured in fibroblasts from the affected subjects. R1881-activated transcription of a GRE-tk-CAT reporter gene construct was strongly diminished by both mutant receptors and was only partially restored using a 100-fold higher concentration of ligand compared with wild-type receptor. Thus, aspartic acid-686 appears essential for normal androgen receptor function. Substitution of this amino acid residue, by either histidine or asparagine, results in androgen insensitivity and lack of androgen-dependent male sexual differentiation.
Mol Endocrinol 1991 Oct
PMID:Substitution of aspartic acid-686 by histidine or asparagine in the human androgen receptor leads to a functionally inactive protein with altered hormone-binding characteristics. 177 37

Superoxide dismutase (SOD) was purified to apparent homogeneity from Dirofilaria immitis, the causative agent of Dog Heartworm disease which is prevalent in the Southeastern United States. The enzyme has a molecular weight of 18,000 under denaturing conditions with an isoelectric point of 5.6. Both values are similar to those found for previously purified helminth SODs. The amino acid analysis shows greater similarity with mammalian SODs than with the published Schistosoma mansoni SOD, probably because the S. mansoni enzyme appears to be an extracellular, not a cytosolic, SOD. Although SOD activity is easily detected in D. immitis homogenates, the hydrogen peroxide scavenging activities of catalase and glutathione peroxidase were below the limits of our assay. This suggests that D. immitis primary defense against oxidants may be SOD. We feel that this line of research may provide valuable insights into a vulnerable area of D. immitis that may be a good target for drug therapy.
Mol Biochem Parasitol 1991 Dec
PMID:Dirofilaria immitis superoxide dismutase: purification and characterization. 177 68

The effect of four fibrate analogues (i.e. clofibrate, ciprofibrate, clobuzarit and 2,4-dichlorophenoxyacetic acid (2,4-D), an active herbicide molecule) were tested on the biogenesis of liver mitochondrial and peroxisomal proteins by rat in vivo treatment at 100 ppm for 26 weeks. The evaluations were done at different levels: somatic index, histochemistry electron microscopy, enzymatic activities on purified peroxisomes and mitochondria, polypeptides electrophoresis and immunolabeling, and finally mRNA hybridization with specific DNA probes. This work shows that the tested hypolipemic agents are strong peroxisomal proliferators especially ciprofibrate, while mitochondria are weakly affected. However, the four fibrates gave different effects, especially 2,4-D which modifies mitochondrial polypeptide pattern. Post-transcriptional study of mRNAs level shows a slight increase in catalase mRNA despite the potential of hypolipemic agents. The peroxisomal acyl-CoA oxidase mRNA content is enhanced with ciprofibrate treatment as well as mitochondrial R-3-hydroxybutyrate dehydrogenase (BDH) mRNA level. Finally, the dual action of ciprofibrate on content and on enzymatic activity of BDH (a lipid metabolism related enzyme) reveals that such a molecule may have differential regulatory effects (positive on gene transcription or mRNA stability and negative on catalytic enzyme activity).
Cell Mol Biol 1991
PMID:Effect of different hypolipemic agents on rat liver peroxisomal and mitochondrial functions and biogenesis. 177 22

Activities of the anti-oxidative enzymes, superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase were studied in rat tissues to determine the ability of detergents both to solubilize the enzymes and also to stabilize enzyme activity. Rat brain, heart and liver were homogenized in 0.1M KCl, 0.1% sodium dodecyl sulfate, 0.1% lubrol, or 0.1% cetyl-trimethylammonium bromide. In general lubrol was more effective than the other solutions in solubilizing GPx and catalase. Lubrol and 0.1M KCl were equally effective in solubilizing SOD. The highest enzyme activities were (1) SOD: 2484 ng/mg (brain), 2501 ng/mg (heart), and 5586 ng/mg (liver); (2) GPx: 224 mU/mg (brain), 1870 mU/mg (heart), and 7332 mU/mg (liver); (3) catalase: 2.8 mU/mg (brain), 10.6 mU/mg (heart), and 309 mU/mg (liver). While cetyl trimethylammonium bromide is marginally better than sodium dodecyl sulfate in solubilizing active enzyme, neither ionic detergent has any advantage over lubrol or 0.1M KCl. For catalase and GPx, enzyme activity loss with time is biphasic. After initial, rapid activity loss (1-5 days for GPx and 7-10 days for catalase) the differences noted among the homogenizing solutions disappear and very little if any activity loss is noted over the next 2-3 weeks. For catalase and GPx, only baseline enzyme activity from t = 0-3 weeks is found in the most chaotropic solution, 0.1% sodium dodecyl sulfate while biphasic activity loss is most pronounced in 0.1% lubrol. These results may indicate active GPx and catalase species stabilized by a lipid-like environment. Correlating in vitro catalase or GPx measurements with in vivo anti-oxidative protection may underestimate tissue defences.
Mol Cell Biochem 1991 Sep 18
PMID:Stability of the anti-oxidative enzymes in aqueous and detergent solution. 178 73

NADH-photosensitized in vitro formation of single-stranded breaks in plasmid DNA pBR322 depends on both the concentration of the sensitizer and the influence of near-UV radiation (320-400 nm). Scavengers and inhibitors of different activated oxygen species (sodium azide, sodium benzoate, catalase and superoxide dismutase) prevent the formation of breaks in full or partly. The data obtained show that hydroxyl radical (.OH) and singlet oxygen (1O2) are directly involved in the induction of breaks. In this process hydrogen peroxide (H2O2) plays the role of an intermediate in the reaction of .OH formation from superoxide anion-radical (O2-.) which is the first NAD.H-photogenerated product.
Mol Biol (Mosk)
PMID:[Mechanism of NADH-sensitized formation of DNA breaks during irradiation with near UV light]. 179 9


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