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 filamentous ascomycete Aspergillus awamori secretes large amounts of glucoamylase upon growth in medium containing starch, glucose, or a variety of hexose sugars and sugar polymers. We examined the mechanism of this carbon source-dependent regulation of glucoamylase accumulation and found a several hundredfold increase in glucoamylase mRNA in cells grown on an inducing substrate, starch, relative to cells grown on a noninducing substrate, xylose. We postulate that induction of glucoamylase synthesis is regulated transcriptionally. Comparing total mRNA from cells grown on starch and xylose, we were able to identify an inducible 2.3-kilobase mRNA-encoding glucoamylase. The glucoamylase mRNA was purified and used to identify a molecularly cloned 3.4-kilobase EcoRI fragment containing the A. awamori glucoamylase gene. Comparison of the nucleotide sequence of the 3.4-kilobase EcoRI fragment with that of the glucoamylase I mRNA (as determined from molecularly cloned cDNA) revealed the existence of four intervening sequences within the glucoamylase gene. The 5' end of the glucoamylase mRNA was mapped to several locations within a region -52 to -73 nucleotides from the translational start. Sequence and structural features of the glucoamylase gene of the filamentous ascomycete A. awamori were examined and compared with those reported in genes of other eucaryotes.
Mol Cell Biol 1984 Nov
PMID:Molecular cloning and characterization of the glucoamylase gene of Aspergillus awamori. 644 4

Several cholesterol autoxidation derivatives known to be cytotoxic to arterial smooth muscle cells both in vivo and in vitro were shown to inhibit hexose transport in these cells in culture. Cholestane-3 beta, 5 alpha, 6 beta-triol was the most potent inhibitory sterol. The rapid onset of inhibition (15 min) and the reversibility of the effect upon removal of the sterol from the tissue culture medium suggests that the effect may be due to incorporation of the sterol into the plasma membrane. 25-Hydroxycholesterol, a potent inhibitor of sterol biosynthesis in cultured arterial smooth muscle cells, did not affect hexose transport up to 8 hr of incubation. The cytotoxic effect of 25-hydroxycholesterol, therefore, may be a consequence of the reduced sterol biosynthesis caused by this sterol.
Exp Mol Pathol 1984 Oct
PMID:Effects of cholesterol autoxidation derivatives on hexose transport in cultured aortic smooth muscle cells. 647 95

Mouse peritoneal macrophages infected with Leishmania parasites were exposed in vitro to the electron carriers methylene blue (MB), toluidine blue 0 (TB), phenazine methosulfate (PMS) and crystal violet (CV). This led to parasite destruction without harm to the macrophages. The kinetics of intracellular killing depended on both the drug concentration and the duration of exposure; over 80% of the microorganisms were inactivated within 2.5 min of incubation of the parasitized cells with 10(-4) M MB. On a molar basis, the drugs were considerably more active against intracellular compared to free parasites, suggesting that the macrophages themselves play a role in the observed anti-parasite toxicity. Intracellular killing by macrophages exposed to MB, TB and PMS correlated with the stimulation of oxygen uptake and hexose monophosphate shunt activity in the cells. Cytochrome c markedly inhibited MB-induced intracellular parasite destruction as well as completely blocking parasite killing in macrophages activated by lymphokines, pointing to O-2, H2O2 or products derived therefrom as possible mediators of macrophage toxic activity in both instances. Cytochrome c did not protect free parasites from the direct toxicity of the drug, however. Lipopolysaccharide promoted parasite destruction by lymphokine-activated macrophages, but failed to do so for electron carrier-stimulated cells. These observations suggest that intracellular killing induced by electron carriers results from a direct interaction of the drugs with cellular redox systems, leading to the generation of oxygen metabolites toxic for the parasites.
Mol Biochem Parasitol 1984 Sep
PMID:Intracellular parasite killing induced by electron carriers. II. Correlation between parasite killing and the induction of oxidative events in macrophages. 651 89

We examined the uptake of 3-O-methyl-D-glucose, a nonmetabolizable hexose, by isolated rat hepatocytes. The uptake of 3-O-methyl-D-glucose was linear for 1 min at 22 degrees, and Lineweaver-Burk analysis demonstrated an apparent Km of approximately 6 mM. Cytochalasin B (40 microM) and phloridzin (2 mM) inhibited 3-O-methyl-D-glucose uptake by 88% and 63%, respectively. D-Glucose (20 mM) inhibited the initial rate of 3-O-methyl-D-glucose uptake by 55% (p less than 0.001), whereas L-glucose was without any significant effect. The uptake of 3-O-methyl-D-glucose remained unchanged in the presence of Na+ (0-150 mM) in the incubation medium. After 30 min dexamethasone inhibited glucose uptake (the maximal effect being achieved in a time- and concentration-dependent manner) at 2 microM and 0.5 microM concentrations by 50% and 25%, respectively. Dexamethasone produced a decrease in the Vmax but did not change the Km. Insulin, glucagon, gastric inhibitory polypeptides, and pancreozymin had no effect on 3-O-methyl-D-glucose uptake in isolated hepatocytes. These findings are consistent with the conclusion that 3-O-methyl-D-glucose uptake in isolated rat hepatocytes occurs via a stereospecific, carrier-mediated, facilitated diffusion process. Dexamethasone decreases this process of facilitated diffusion in the isolated hepatocyte.
Mol Pharmacol 1983 Jan
PMID:3-O-methyl-D-glucose uptake in isolated rat hepatocytes. Effects of dexamethasone. 686 98

Glycolytic parameters were determined in recessive yeast mutants with partial defects in carbon catabolite repression. Specific activities of pyruvate kinase and pyruvate decarboxylase in glucose grown cells of all mutant and wild type strains were 4--5 times higher than in ethanol grown cells. Mutants of gene HEX1 had a reduced hexose phosphorylating activity on all media whereas those of gene HEX2 had elevated levels but only in glucose grown cells. Mutants of gene CAT80 were normal in this respect. All other glycolytic enzymes were normal in all mutants. This was also true for glycolytic intermediates. Only hex1-mutants showed a reduced fermentation of repressing sugars. The three genes appear to be involved in catabolite repression of several but not of all repressible enzymes. Even though all three types of mutants show a limited overlap in their effects on certain enzymes, they still are distinctly different in their action spectra. Carbon catabolite repression apparently does not depend on the sole accumulation of glycolytic intermediates. The activity of the products of the three genes HEX1, HEX2 and CAT80 are required directly or indirectly for triggering carbon catabolite repression. Even a small segment of carbon catabolite repression is controlled by several genes with regulatory functions indicating that the entire regulatory circuit is highly complex.
Mol Gen Genet 1980 Jan
PMID:Glycolytic enzymes and intermediates in carbon catabolite repression mutants of Saccharomyces cerevisiae. 698 75

A major antigen inducing IgE in mice (DpI) was purified from a crude extract of Dermatophagoides pteronyssinus (D.p.) using Sephacryl S-200 gel filtration, DE52 ion exchange chromatography and isoelectric focusing. This antigen is not one of the major D.p. human allergens. Isoelectric focusing showed a single peak of PCA activity at pI 4.7. Activity followed a broader banding pattern on polyacrylamide gel electrophoresis (PAGE). The molecular weight of DpI estimated from Sephadex G-150 chromatography was 1.7 X 10(5) daltons. Molecular weight calculated from SDS-gels (reducing), however, was 3.7 X 10(4), which may indicate a molecule with a subunit composition. DpI contained no detectable hexose as measured by the phenol-sulfuric acid assay. PCA activity of DpI was stable at 98 degrees C and to treatment with 0.1 M sodium metaperiodate, but destroyed by pronase. DpI represents approximately one per cent of the total protein of crude extracts. Purified DpI displays a specific activity increase of 40 times that of the crude extract with the PCA test. DpI is capable of inhibiting 40% of the binding between crude extract and human IgE, but only at extremely high concentrations. Human IgE was 700 times more sensitive to D.p. crude extract than purified DpI by enzyme immunoassay.
Mol Immunol 1982 Feb
PMID:Purification of a murine IgE-inducing antigen extracted from the house dust mite, Dermatophagoides pteronyssinus. 704 69

The influence of dexamethasone on the isozyme patterns of ATP-hexose phosphotransferases, aldolase and pyruvate kinase of adult rat hepatocytes maintained in primary cultures has been studied. A progressive loss of the typical adult liver isozymes glucokinase, pyruvate kinase L and aldolase B, with a simultaneous increase of both pyruvate kinase A and hexokinase activities, was observed in hepatocytes cultured in the absence of added glucocorticoid. When the culture medium was supplemented with 10(-7)M dexamethasone, the adult liver patterns of pyruvate kinase and aldolase were preserved for at least seven days of culture, the initial level of glucokinase was maintained for three days, and the rise of hexokinase activity was delayed and partially blocked. These results are discussed in relation to the known beneficial effect of glucocorticoids on the survival of cultured hepatocytes.
Mol Cell Biochem 1982 Jun 11
PMID:Effect of dexamethasone on the isozyme pattern of adult rat liver parenchymal cells in primary cultures. 711 Jan 29

A steady-state compartmental analysis of galactose, glucose and 3-O-methylglucose fluxes was conducted on male and female Schistosoma mansoni. The method has several advantages over previously used initial rate studies. A nonlinear log-linear plot of glucose exchange is discussed in terms of differentiating between metabolized and nonmetabolized substrates in transport studies. Kt values and marker distribution volumes are estimated from the compartmental analysis and it is concluded that 3-O-methylglucose is not suited as a substrate for hexose transport studies in S. mansoni.
Mol Biochem Parasitol 1982 Jun
PMID:A method for determining nonelectrolyte uptake by adult schistosoma mansoni using compartmental analysis of hexose fluxes. 711 Jan 96

Yeast cells can respond and adapt to osmotic stress. In our attempt to clarify the molecular mechanisms of cellular responses to osmotic stress, we cloned seven cDNAs for hyperosmolarity-responsive (HOR) genes from Saccharomyces cerevisiae by a differential screening method. Structural analysis of the clones revealed that those designated HOR1, HOR3, HOR4, HOR5 and HOR6 encoded glycerol-3-phosphate dehydrogenase (Gpd1p), glucokinase (Glk1p), hexose transporter (Hxt1p), heat-shock protein 12 (Hsp12p) and Na+, K+, Li(+)-ATPase (Ena1p), respectively. HOR2 and HOR7 corresponded to novel genes. Gpd1p is a key enzyme in the synthesis of glycerol, which is a major osmoprotectant in S. cerevisiae. Cloning of HOR1/GPD1 as a HOR gene indicates that the accumulation of glycerol in yeast cells under hyperosmotic stress is, at least in part, caused by an increase in the level of GPDH protein. We performed a series of Northern blot analyses using HOR cDNAs as probes and RNAs prepared from cells grown under various conditions and from various mutant cells. The results suggested that all the HOR genes are regulated by common signal transduction pathways. However, the fact that they exhibited certain distinct responses indicated that they might also be regulated by specific pathways in addition to the common pathways. Ca2+ seemed to be involved in the signaling systems. In addition, Hog1p, one of the MAP kinases in yeast, appeared to be involved in the regulation of expression of HOR genes, although its function seemed to be insufficient for the overall regulation of expression of these genes.
Mol Gen Genet 1995 Nov 15
PMID:Cloning and characterization of seven cDNAs for hyperosmolarity-responsive (HOR) genes of Saccharomyces cerevisiae. 750 Sep 33

In order to test the assumption that red blood cell (RBC) uridine diphosphate galactose content is regulated in part by dietary galactose and to help comprehend factors influencing RBC and white blood cell (WBC) uridine diphosphate hexose concentrations in vivo, oral loading studies were performed with 50 g of galactose or 75 g of glucose in normal adults. While elevations of blood glucose did not influence RBC or WBC UDPhexose levels, increased blood galactose concentrations caused transient increases in both RBC and WBC UDPgalactose. In both RBC and WBC, the UDPgalactose-4-epimerase was rate limiting. In comparison to RBC, WBC had larger changes in UDPgalactose levels, synthesized additional UDPglucose through the action of UDPglucose pyrophosphorylase and began to restore the equilibrium ratio between UDPglucose and UDPgalactose concentrations while the plasma galactose level was still increasing. Thus, galactose ingestion alters the steady-state levels of UDPhexoses in circulating cells. The modulation of UDPglucose and UDPgalactose concentrations, occurring after the presentation of galactose to cells, as a result of the combined actions of GALT and UDPgalactose-4-epimerase, may be important in determining rates of synthesis of complex glycoconjugates.
Biochem Mol Med 1995 Jun
PMID:Effect of glucose and galactose loading in normal subjects on red and white blood cell uridine diphosphate sugars. 755 32


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