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 microsomal fraction of insects was found to contain an enzyme which transfers mannose from guanosine diphosphate mannose to an endogenous or exogenous insect lipid and to other acceptors such as dolichol monophosphate or ficaprenol monophosphate. This activity depended on the presence of Triton X-100 and magnesium ions, the optimal concentration of the latter being 10mM. The optimal temperature of the reaction was 25 degrees C and the maximal activity was obtained at pH 7.9. The mannolipid formed behaved as a monophosphodiester when chromatographed on DEAE-cellulose. Weak acid treatment of the product liberated mannose. Its behaviour both on thin layer and Sephadex G-150 chromatography would indicate the presence of a number of isoprenyl units similar to the dolichol and different from the ficaprenol derivative. Stability to phenol treatment indicated that the lipid fraction of the mannolipid is an alpha-saturated polyprenol phosphate similar to dolichol monophosphate.
Mol Cell Biochem 1977 Jul 05
PMID:Enzymatic synthesis of polyprenol monophosphate mannose in insects. 1 65

An enzyme preparation from embryonic chicken brain catalyzes the transfer of sialic acid from CMP-N-acetylneuraminic acid to ceramide-Glc-Gal(NeuAc-NeuAc)-GalNAc-Gal (GDlb) to form ceramide-Glc-Gal(NeuAc-NeuAc)-GalNAc-Gal-NeuAc (GTlb). The sialyltransferase activity was measured during the development of the embryo, the subcellular distribution of this activity was determined and several kinetic properties of the reaction were examined. A comparative study with the similar reaction involved in the transfer of sialic acid to the terminal galactose in ceramide-Glc-Gal(NeuAc)-GalNAc-Gal (GMl) was made. The results obtained in this comparative study suggest that the transfer of sialic acid in both reactions is catalyzed by the same enzyme.
Mol Cell Biochem 1977 Jul 05
PMID:Trisialoganglioside synthesis by a chicken brain sialyltransferase. Comparative study with the similar reaction for the synthesis of disialoganglioside. 1 68

It could be shown that Streptomyces griseus, the microorganism producing the antibiotic streptomycin and also mutant strains of this species that cannot synthesize streptomycin, possess myo-inositol-1-phosphate synthase (EC 5.5.1.4), the enzyme cyclizing D-glucose 6-phosphate. The enzyme isolated from that organism is extremely instable, its molecular weight is approximately 260,000, and it requires a divalent metal ion for its activity. This is the first instance that an enzyme of this specificity has been found in a prokaryotic organism.
Mol Cell Biochem 1979 May 06
PMID:Myo-inositol-1-phosphate synthase from streptomyces griseus (studies on the biosynthesis of cyclitols, XXXVIII). 3 95

2-Deoxy-D-galactose, in a dose of 3 mmol/kg, was administered intraperitoneally twice daily to young rats for periods up to 12 weeks. This dosage schedule resulted in recurrent phosphate trapping predominantly in liver. UTP deficiency was excluded by simultaneous uridine injections. Phosphate trapping was caused by the rapid accumulation of 2-deoxy-D-galactose 1-phosphate and was most pronounced in liver but also demonstrated in small intestine, brain, spleen, and thymus. The marked, although transient, drop in the hepatic content of inorganic phosphate triggered the catabolism of adenine nucleotides and a loss of ATP. Other metabolic pathways affected by phosphate deficiency include glycogenolysis and glycolysis. Increasing with time, repeated doses of the galactose analog led to retardation and arrest of growth, hepatomegaly, and splenomegaly. The average relative liver and spleen weights were elevated 2.5- and 4.5-fold, respectively, after 12 weeks of treatment. Liver damage was indicated by hyperbilirubinaemia and a progressive rise in the activity in plasma of sorbitol dehydrogenase, alkaline phosphatase, and gamma-glutamyltransferase. Examination by light and electron microscopy showed increasing numbers of vacuoles, surrounded by a single membrane, in hepatocytes, sinusoidal endothelial cells, and Kupffer cells. Focal cytoplasmic degeneration in hepatocytes was occasionally indicated by formation of autophagic vacuoles and finger print lysosomes. Hepatocytes of 2-deoxy-D-galactose-treated rats showed a dissociation and fragmentation of the rough endoplasmic reticulum. Sinusoidal endothelial cells and Kupffer cells were markedly enlarged, the latter contained a PAS-positive but amylase resistant substance. Extrahepatic changes included an increased occurrence of vacuolated cells in thymus. Phosphate trapping and its metabolic consequences are common phenomena in the experimental injury induced b 2-deoxy-D-galactose and in some hereditary diseases such as uridylyltransferase deficiency galactosaemia, fructose intolerance and glucose-6-phosphatase deficiency.
Virchows Arch B Cell Pathol Incl Mol Pathol 1979 Jun 29
PMID:Consequences of recurrent phosphate trapping induced by repeated injections of 2-deoxy-D-galactose. Biochemical and morphological studies in rats. 4 10

1. The effects in rats of an oral pharmacological dose of prednisolone on mucosal function, enzymology, lysosomal membrane fragility, morphology and cell kinetics have been examined in proximal jejunum and distal ileum. 2. The maximum absorptive capacity for galactose was significantly greater in both the jejunum and the ileum of the steroid-treated animals. This was due to an increase in carrier-mediated transport in the individual enterocytes and not to a change in the cell population. The Michaelis constant for galactose was not significantly altered by prednisolone. 3. Activities of brush-border and mitochondrial enzymes and of RNA were increased in isolated enterocyte preparations from the jejunum and ileum of the steroid-treated group. 4. Lysosomal membrane fragility was unaltered in the prednisolone-treated group. 5. Morphometrical observations confirmed that the size of the enterocyte population was unaltered by prednisolone. Studies on cell kinetics indicate that the effects of prednisolone are due to a direct action on the enterocyte and not secondary to changes in migration rate.
Clin Sci Mol Med 1976 Jun
PMID:Effects of prednisolone on the small intestinal mucosa of the rat. 17 52

We have proposed that glucose-6-phosphatase (EC 3.1.3.9) is a two-component system consisting of (a) a glucose-6-P-specific transporter which mediates the movement of the hexose phosphate from the cytosol to the lumen of the endoplasmic reticulum (or cisternae of the isolated microsomal vesicle), and (b) a nonspecific phosphohydrolase-phosphotransferase localized on the luminal surface of the membrane (Arion, W.J., Wallin, B.K., Lange, A.J., and Ballas, L.M. (1975) Mol. Cell. Biochem. 6, 75-83). Additional support for this model has been obtained by studying the interactions of D-mannose-6-P and D-mannose with the enzyme of untreated (i.e. intact) and taurocholate-disrupted microsomes. An exact correspondence was shown between the mannose-6-P phosphohydrolase activity at low substrate concentrations and the permeability of the microsomal membrane to EDTA. The state of intactness of the membrane influenced the kinetics of mannose inhibition of glucose-6-P hydrolysis; uncompetitive and noncompetitive inhibitions were observed for intact and disrupted microsomes, respectively. The apparent Km for glucose-6-P was smaller with intact preparations at mannose concentrations above 0.3 M. Mannose significantly inhibited total glucose-6-P utilization by intact microsomes, whereas D-glucose had a stimulatory effect. Both hexoses markedly enhanced the rate of glucose-6-P utilization by disrupted microsomes. The actions of mannose on the glucose-6-phosphatase of intact microsomes fully support the postulated transport model. They are predictable consequences of the synthesis and accumulation of mannose-6-P in the cisternae of microsomal vesicles which possess a nonspecific, multifunctional enzyme on the inner surface and a limiting membrane permeable to D-glucose, D-mannose, glucose-6-P, but impermeable to mannose-6-P. The latency of the mannose-6-P phosphohydrolase activity is proposed as a reliable, quantitative index of microsomal membrane integrity. The inherent limitations of the use of EDTA permeability for this purpose are discussed.
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PMID:Microsomal membrane permeability and the hepatic glucose-6-phosphatase system. Interactions of the system with D-mannose 6-phosphate and D-mannose. 18 83

Angiotensin-converting enzyme from rabbit serum was purified almost 60,000-fold to apparent homogeneity by a procedure exploiting its affinity for antibodies prepared against the enzyme from lung. The pure serum and pulmonary enzymes exhibited identical behavior during gel filtration, sucrose gradient centrifugation, and disc gel electrophoresis in the reduced, denatured state. Their catalytic properties with hippurylhistidylleucine, angiotensin I, and bradykinin as substrates were similar and their reactivity with antilung enzyme antibody was indistinguishable as examined by immunodiffusion, inhibition dose-response curves, and radioimmunoassay. Their content of fucose, mannose, galactose, and N-acetylglucosamine was also comparable; however, N-acetylneuraminic acid was much more abundant in the serum glycoprotein. This difference may reflect selective removal of sialic acid-deficient enzyme molecules from the circulation by the hepatic lectin which has been postulated to initiate the catabolic phase for plasma glycoproteins (Ashwell, G., and Morell, A.G. (1974) Adv. Enzymol. Relat. Areas Mol. Biol. 41, 91-128).
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PMID:Serum angiotensin-converting enzyme. Isolation and relationship to the pulmonary enzyme. 19 Feb 28

Strains of Escherichia coli K12 that contain a deletion of the adenyl cyclase gen (cya delta), required for the synthesis of cyclic adenosine-3';5' monophosphate (cAMP), grow on galactose-containing minimal medium. A mutant was isolated that grows on this medium only if cAMP is added. The mutation (designated galP20) is linked to the gal operon region as determined by both generalized transduction with bacteriophage P1 and specialized transduction with bacteriophage lambda. Studies with galP20 cya delta strains as well as gal delta (deletions of the gal operon) cya delta strains indicate that synthesis of the physiologically important transport mechanism for galactose (galactose permease) requires either cAMP or a function mission from both the galdelta strains and the galP20 strain.
Mol Gen Genet 1977 Jan 18
PMID:A gal region mutant that requires cAMP for growth on galactose in an adenyl cyclase negative (cya delta) background. 19 May 30

The expression of cell cycle events in Caulobacter crescentus CB13 has been shown to be associated with regulation of carbohydrate utilization. Growth on lactose and galactose depends on induction of specific enzymes. Prior growth on glucose results in a delay in enzyme expression and cell cycle arrest at the nonmotile, predivisional stage. Dibutyryl cyclic adenosine 3',5'-monophosphate (AMP) was shown to stimulate expression of the inducible enzymes and, thus, the initiation of the cell cycle. beta-Galactosidase-constitutive mutants did not exhibit a cell cycle arrest upon transfer of cultures from glucose to lactose. Furthermore, carbon source starvation results in accumulation of the cells at the predivisional stage. The cell cycle arrest therefore results from nutritional deprivation and is analogous to the general control system exhibited by yeast (Hartwell, Bacteriol. Rev. 38:164-198, 1974; Wolfner et al., J. Mol. Biol. 96:273-290, 1975), which coordinates cell cycle initiation with metabolic state. Transfer of C. crescentus CB13 from glucose to mannose did not result in a cell cycle arrest, and it was demonstrated that this carbon source is metabolized by constitutive enzymes. Growth on mannose, however, is stimulated by exogenous dibutyryl cyclic AMP without a concomitant increase in the specific activity of the mannose catabolic enzymes. The effect of cyclic AMP on growth on sugars metabolized by inducible enzymes, as well as on sugars metabolized by constitutive enzymes, may represent a regulatory system common to both types of sugar utilization, since they share features that differ from glucose utilization, namely, temperature-sensitive growth and low intracellular concentrations of cyclic guanosine 3',5'-monophosphate.
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PMID:Effect of carbon source and the role of cyclic adenosine 3',5'-monophosphate on the Caulobacter cell cycle. 19 60

The fdp mutation has been localized on the genome of Saccharomyces carlsbergensis, on chromosome II, between lys2 and tyr1, at a man distance of 31 centimorgan from lys2. Since the fdp mutant does not grow on glucose, fructose, mannose and sucrose, hexose transport and a number of enzymes of carbon metabolism were tested, but no significant differences could be found between the wild type and the mutant. Only the regulatory properties of glycogen synthetase are changed in the mutant, but it is doubtful whether this can explain its phenotype. The disorganization of carbon metabolism of the mutant upon addition of glucose to the medium was analyzed in more detail. The most prominent feature observed until now is the accumulation of free glucose and hexose phosphates in the cell. This result indicates that somehow the feedback control between hexose transport and metabolism is impaired. Hexose phosphates are known to be toxic to many cells, including yeast. Therefore, accumulation of hexose phosphates in the presence of glucose in the medium, can explain the absence of growth on this carbon source.
Mol Gen Genet 1977 Jul 07
PMID:Characterization of a regulatory mutant of fructose 1,6-bisphosphatase in Saccharomyces carlsbergensis. 19 89


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