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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Microsomal preparations from malignant human breast tumors catalyzed the transfer of mannose and glucose from GDP-[14C]-Man and UDP-[14C]-Glc into lipid-linked sugars and glycoprotein-like substances. As judged by several criteria the obtained lipid-linked monosaccharides behaved as dolichyl phosphate mannose and dolichyl phosphate glucose whereas lipid-linked oligosaccharides behaved as polyprenyl diphosphate derivatives. The optimum conditions for mannosyl- and glucosyl-transfer reactions and the effect of dolichyl phosphate, detergent and EDTA on incubation mixture were described.
Mol Cell Biochem 1983
PMID:Lipid-bound sugars in malignant human breast tumors. Partial characterization of mannosyl and glucosyl transferase activities. 619 18

Trichomonas vaginalis is incapable of de novo pyrimidine biosynthesis because it cannot incorporate bicarbonate, aspartate or orotate into its pyrimidine nucleotides or nucleic acids. The organism can salvage exogenous cytidine greater than uridine greater than uracil and thymidine, and incorporate them into the nucleotide pool. A portion of cytidine is converted to CMP, CDP and CTP by cytidine phosphotransferase and nucleotide kinases. Some cytidine and most of uracil are, however, converted first to uridine by cytidine deaminase and uridine phosphorylase respectively; uridine is then incorporated into UMP, UDP and UTP by uridine phosphotransferase and nucleotide kinases. The two phosphotransferases, found mainly in the non-sedimentable fraction of T. vaginalis, provide the main avenue of pyrimidine salvage. No significant levels of pyrimidine phosphoribosyl transferase or nucleoside kinases can be detected in the extract. T. vaginalis has no appreciable dihydrofolate reductase or thymidylate synthetase; it grows normally in millimolar concentrations of methotrexate, pyrimethamine, or trimethoprim, and cannot incorporate labels from exogenous uracil or uridine into DNA. It has an enzyme thymidine phosphotransferase in the sedimentable fraction which converts thymidine to TMP. Thymidine salvage in T. vaginalis is thus totally isolated from the rest of the pyrimidine salvage.
Mol Biochem Parasitol 1984 Feb
PMID:Salvage of pyrimidine nucleosides by Trichomonas vaginalis. 619 66

Maximal binding (Bmax) of the lectin, wheat germ agglutinin, by small intestinal brush border membrane is significantly reduced in rats infected with Trichinella spiralis. Wheat germ agglutinin specificity is for N-acetylglucosamine and sialic acid. Whereas total hexosamine and N-acetylglucosaminidase-labile N-acetylglucosamine were comparable in membranes from uninfected as compared with infected rats, the total sialic acid content and neuraminidase-released sialic acid were significantly higher in BBM from uninfected hosts. N-Acetylglucosaminidase treatment of membranes reduced Bmax for wheat germ agglutinin in both hosts. Neuraminidase treatment reduced Bmax in uninfected hosts, but tended to increase it in infected rats. Membranes from uninfected rats incorporated more N-acetylglucosamine from UDP-N-[14C]acetylglucosamine into oligosaccharide-lipid than did membranes from infected hosts. However, lipid and protein fractions were labeled at the same rate in both sets of membranes. Sialic acid was incorporated into protein at a slightly faster rate in brush border membrane from uninfected rats, indicative of a higher level of sialotransferase activity. These results suggest that the reduction in Bmax for wheat germ agglutinin in gut epithelial cell membranes from infected rats is related to a reduced level of sialic acid available for lectin binding as well as specific interactions between N-acetylglucosamine and sialic acid.
Mol Biochem Parasitol 1983 Sep
PMID:Sialic acid deficiency in lectin-resistant intestinal brush border membranes from rats following the intestinal phase of trichinellosis. 666 61

The levels of ribonucleotides in the nematodes Haemonchus contortus, Ostertagia circumcincta, Trichostrongylus colubriformis, Nippostrongylus brasiliensis, Ascaris suum and Stephanurus dentatus, the cestode Moniezia expansa and the trematode Fasciola hepatica were measured by high pressure liquid chromatography. The adenylate charge, ATP and total adenine nucleotide levels were in general agreement with those determined enzymatically and with published data. UDP and guanine nucleotide levels were found to be higher than those present in mammals and previously reported for helminth parasites. Cytidine nucleotide levels varied considerably between parasite species. On the other hand inosine nucleotides were present at low concentrations in all species. Adenylate and guanylate charges were similar.
Mol Biochem Parasitol 1983 Jun
PMID:Ribonucleotide levels in six nematodes, a cestode and a trematode. 687 82

Cell wall fragments from both yeast-like and mycelial forms of the dimorphic fungus Mucor rouxii were used as enzymatic preparations to study the synthesis and role of prenyl-phospho-sugars in these systems. In the presence of GDP [14C] mannose two main products were formed. One of them was characterized as dolichol-monophosphate beta-mannose on the following basis: solubility in organic solvents, behaviour upon paper chromatography, DEAE cellulose column chromatography, mild acid hydrolysis, alkali treatment, catalytic reduction and phenol degradation. The other product was identified as a glycoprotein containing a single mannose unit linked to a serine or threonine residue. It was degraded with pronase and by mild NaOH-NaBH4 treatment all the radioactivity was released as free mannitol. When UDP [14C] glucose was employed as sugar donor two butanol soluble components were isolated. One of them (25%) was characterized as dolichol-monophosphate-beta-glucose on the basis of the same criteria as described above. The other one (75%) was neutral and was not studied in detail. Mycelial enzymes were about 40 times more active in the synthesis of the dolichol derivatives. In addition, large amounts of glycogen were detected. The role that both dolichol derivatives might play in glycoprotein biosynthesis is discussed.
Mol Cell Biochem 1982 May 28
PMID:Formation of lipid-linked sugars in mycelial and yeast-like forms of Mucor rouxii. 711 Jan 24

Results of previous studies indicate that culture of preimplantation mouse embryos in SOM medium containing 85 mM NaCl promotes better development in vitro, as well as supporting higher rates of protein synthesis, when compared to culture in SOM containing 125 mM NaCl (Anbari and Schultz, 1993, Mol Reprod Dev 35:24-28; Biggers et al., 1993, Mol Reprod Dev 34:380-390). In the present study we compare the effect of culturing embryos in these 2 media on several aspects of RNA synthesis and gene expression in order to determine whether the reduced development in SOM containing 125 mM NaCl and lower rates of protein synthesis are correlated with decreases in RNA synthesis and stability and changes in gene expression. Although no apparent differences in the metabolism of [3H]uridine to UMP, UDP, and UTP and its incorporation into total RNA are observed when 2-cell embryos are cultured to the morula stage in either medium, a 20% decrease in the rate of mRNA synthesis is found when embryos are cultured in SOM containing 125 mM NaCl. In addition, pulse-chase experiments reveal that total mRNA is less stable when the embryos are cultured in SOM containing 125 mM NaCl. Using a reverse transcription-polymerase chain reaction to assay for changes in the relative amounts of specific mRNAs, the relative amounts of mRNAs for IGF-I and IGF-II and their cognate receptors are dramatically reduced in embryos cultured in SOM containing 125 mM NaCl, whereas only a mild reduction is observed in the relative amount of actin mRNA. In contrast, when freshly isolated morulae are cultured to the blastocyst stage in either of these 2 media, similar amounts of these mRNAs are observed. Last, high-resolution, 2-dimensional gel electrophoresis reveals significant changes in the pattern of protein synthesis when the embryos are cultured in SOM containing 125 mM NaCl. Results of these experiments suggest that culture of embryos in medium containing lower concentrations of NaCl that are normally present in various culture media results in higher rates of mRNA synthesis and greater mRNA stability. These changes in RNA synthesis may underlie, at least in part, the improved development in vitro that is fostered by SOM containing 85 mM NaCl.
Mol Reprod Dev 1994 Jun
PMID:Mouse preimplantation embryo development in vitro: effect of sodium concentration in culture media on RNA synthesis and accumulation and gene expression. 752 50

Spatially localized 31P NMR spectroscopy was used to assay in vivo the liver of intact rats fed orotic acid (OA) in a diet which produces hepatic steatosis. Twenty-three sets of multiple volume spectra were obtained from twenty-one 265- to 315-g female rats after 0-9 days of feeding either a 1% OA/64% sucrose diet (12 rats) or a 65% sucrose control diet (9 rats). The intensity of the in vivo diphosphodiester resonance ascribed to UDP-hexos(amin)es increased and the phosphomonoester resonance decreased in intensity prior to fatty infiltration. High resolution NMR spectroscopy of extracts of these livers indicated that the UDP-hexos(amin)e peak included four different UDP-sugars including UDP-N-acetylglucosamine (UDP-glcNAc), and that lower phosphocholine (P-Cho) accounted for the lower phosphomonoester resonance in vivo. Increased UDP-glcNAc is thought to reflect impaired lipoprotein glycosylation as a mechanism for hepatic steatosis in orotic acid feeding. P-Cho deficiency has been shown to be due to an increased rate of phosphatidylcholine synthesis. Low P-Cho concentration has been shown to be associated with lipid accumulation in a choline-deficient diet, but was not previously associated with hepatic steatosis in OA feeding. Changes in phosphorus metabolites were observed 2 days prior to development of fatty liver. HPLC assay of uridine nucleotides showed a good correlation between magnetic resonance spectroscopy and HPLC quantitation. In this study there were two biochemical correlates of impaired hepatic lipid secretion detectable by in vivo assay with 31P NMR spectroscopy. This method has application for noninvasive assays in ornithine transcarbamylase-deficient patients.
Biochem Mol Med 1995 Feb
PMID:An in vivo 31P magnetic resonance spectroscopy study of uridine excess in rats fed orotic acid. 755 16

The GST (glutathione S-transferase)-NDK (nucleoside diphosphate kinase) fusion protein was expressed in Escherichia coli. The GST-NDK protein was capable of transferring gamma-phosphate from ATP to nucleoside diphosphates such as GDP, CDP, TDP and UDP. Western blot analysis using anti-NDK antibody indicated that NDK in endosperm gradually decreased during 36 h of imbibition. On the contrary, NDK in embryo increased during the same period. NDK activities in both tissues were in accord with these observations. Whereas the NDK protein in roots of rice seedlings during 7 days of imbibition remained constant, in shoots it declined after 5 days of imbibition. Thus, NDK may play a significant role in the cellular event modulated by adenylate energy charge level.
Plant Mol Biol 1995 Mar
PMID:Expression of functional proteins of cDNA encoding rice nucleoside diphosphate kinase (NDK) in Escherichia coli and organ-related alteration of NDK activities during rice seed germination (Oryza sativa L.). 776 75

The Rhizobium nodulation genes nodABC are involved in the synthesis of lipo-chitin oligosaccharides. We have analysed the metabolites which are produced in vivo and in vitro by Rhizobium strains which express the single nodA, nodB and nodC genes or combinations of the three. In vivo radioactive labelling experiments, in which D-[1-14C]-glucosamine was used as a precursor, followed by mass spectrometric analysis of the purified radiolabelled metabolic products, showed that Rhizobium strains that only express the combination of the nodB and nodC genes do not produce lipo-chitin oligosaccharides but instead produce chitin oligomers (mainly pentamers) which are devoid of the N-acetyl group on the non-reducing terminal sugar residue (designated NodBC metabolites). Using the same procedure we have shown that when the nodL gene is expressed in addition to the nodBC genes the majority of metabolites contain an additional O-acetyl substituent on the non-reducing terminal sugar residue (designated NodBCL metabolites). The NodBC and NodBCL metabolites purified after in vivo labelling were compared with the radiolabelled metabolites produced in vitro by Rhizobium bacterial cell lysates to which UDP-N-acetyl-D-[U-14C]-glucosamine was added using thin-layer chromatography. The results show that the lysates of strains which expressed the nodBC or nodBCL genes can also produce NodBC and NodBCL metabolites. The same results were obtained when the NodB and NodC proteins were produced separately in two different strains. On the basis of these and other recent results, we propose that NodB is a chitin oligosaccharide deacetylase, NodC an N-acetylglucosaminyltransferase and, by default, NodA is involved in lipid attachment.
Mol Microbiol 1994 Sep
PMID:Structural identification of metabolites produced by the NodB and NodC proteins of Rhizobium leguminosarum. 781 41

From an extract of milk-ripe stage rice grains, four sucrose synthase activities could be separated by a FPLC Mono Q column. They are considered isozymes because they show different electrophoretic mobilities in a non-denaturing gel. However, the migration rates of their subunits in SDS-PAGE were indistinguishable and had a molecular mass of 94 kDa. The native forms had identical molecular mass of 440 kDa, thus they were considered to be tetrameric but carrying different ionic charges. Ouchterlony assay indicates that they have the same epitopes. All isozymes use UDP as the best nucleoside diphosphate substrate. When characterized by the ratio of catalytic rates of sucrose synthesizing and cleaving reactions, the isozyme that had the slowest migration rate in PAGE had the smallest value.
Biochem Mol Biol Int 1994 Oct
PMID:Purification and characterization of rice sucrose synthase isozymes. 783 39


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