Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.2.1.24 (alpha-mannosidase)
1,509 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A cbh2 cDNA encoding Trichoderma reesei QM9414 cellobiohydrolase II, located on the expression vector whose copy number is controlled by the level of gentamicin, was successfully expressed under the control of a human cytomegalovirus promoter in the fission yeast. Schizosaccharomyces pombe. The 24-amino-acid leader peptide of the cbh2 gene was recognized by the yeast, enabling the efficient secretion of the heterologous cellobiohydrolase. The transformed S. pombe strain produced over 115 micrograms cellobiohydrolase proteins/ml rich medium supplemented with malt extract and 100 micrograms/ml gentamicin. The molecular masses of the recombinant cellobiohydrolases, secreted as two molecular species, were estimated to be 70 kDa and 72 kDa by sodium dodecyl sulfate/polyacrylamide gel electrophoresis (SDS-PAGE). Deglycosylation treatments revealed that the recombinant enzymes were overglycosylated and scarcely susceptible to alpha-mannosidase. The recombinant enzymes showed no carboxymethylcellulase activity, but showed similar characteristics to those of a native enzyme purified from T. reesei in their optimum pH and temperature, pH and temperature stabilities, and Vmax values toward phosphoric-acid-swollen cellulose as substrate, except that their Km values were about four-fold higher than that of the native enzyme.
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PMID:Efficient secretion of Trichoderma reesei cellobiohydrolase II in Schizosaccharomyces pombe and characterization of its products. 958 Dec 94

This study demonstrates that alpha-mannosidase from rat epididymal fluid is a ligand for phosphomannosyl receptors on the sperm surface. This enzyme was bound to intact epididymal spermatozoa with high affinity and in saturable form, and the binding was inhibited by mannose-6-phosphate but not by phosphorylated derivatives of fructose. Treatment of the enzyme with sodium periodate inhibited the binding of alpha-mannosidase, confirming that a carbohydrate residue is involved in the interaction with spermatozoa. Evidence is also presented that the cation-independent phosphomannosyl receptors are responsible for the interaction with alpha-mannosidase. These findings suggest a new role for extracellular transport mediated by the mannose-6-phosphate receptor.
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PMID:alpha-Mannosidase from rat epididymal fluid is a ligand for phosphomannosyl receptors on the sperm surface. 980 43

Chick kidney and brain were analyzed for the subcellular distribution (if any) of a putative plasma membrane receptor for 1,25-dihydroxyvitamin D3 [1,25(OH)2D3]. Fractionation protocols were found to be based not only on differential centrifugation conditions, but also gentleness of resuspension procedures, and sufficiently dense Percoll gradients. The postnuclear pellets were resolved on 21.85% Percoll gradients overlayed on 2.4 M sucrose cushions. For both kidney and brain, fraction 1 (bottom of tube) was found to be enriched over whole homogenate 5.4- and 1.6-fold, respectively, in acid phosphatase activity, fractions 2 through 5 were enriched four- and eightfold, respectively, in succinate dehydrogenase activity, fraction 8 contained Golgi, as judged by a small peak of alpha-mannosidase activity, and fraction 9 was enriched sevenfold (for each tissue) in Na+,K+-ATPase activity. Western analyses, using a characterized antibody to the putative chick intestinal plasma membrane vitamin D receptor, revealed the highest levels of antigenicity in both chick kidney and brain in plasma membrane and Golgi fractions, followed by unidentified membranes in fractions 6 and 7 of Percoll gradients. Distribution of specific binding of [3H]1,25(OH)2D3 in Percoll gradient fractions paralleled that of antigenicity. Qualitatively, kidney plasma membrane contained more antigen than brain plasma membrane after Western blot analyses; these results were mirrored by differences in specific binding of the tritiated secosteroid (65 +/- 14.5 and 34 +/- 11.9 fmol/mg of protein, respectively).
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PMID:Immunochemical studies on the putative plasmalemmal receptor for 1,25-dihydroxyvitamin D3 II. Chick kidney and brain. 1049

An alpha-mannosidase from Trypanosoma rangeli was partially purified by a protocol involving solubilization using lysis buffer followed by chromatography on diethylaminoethyl (DEAE)-cellulose and Sephadex 100 columns. The enzyme has a molecular weight of 45 kDa as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and of 90 kDa as determined by gel filtration. The purified T. rangeli alpha-mannosidase has a pH optimum ranging between 5 and 6 and a temperature optimum of 37 degrees C. It has activation energy of 8.15 x 10(2) J mol(-1) K(-1). The enzyme has a Michaelis constant (Km) of 99 microM for the 4-methylumbelliferyl-alpha-D-mannopyranoside substrate (MU-alpha-mann). It is strongly inhibited by swainsonine [inhibition constant (Ki) 0.048 microM] and is moderately inhibited by mannose and alpha-D-methylmannopyranoside. The enzyme activity is decreased in the presence of 1 mM Ca2+, Co2+, Cu2+, Fe2+, Fe3+, Hg2+, Mg2+, and Mn2+.
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PMID:Purification and partial characterization of alpha-mannosidase from Trypanosoma rangeli. 1109 1

Japanese eel immunoglobulin M (IgM) was purified from the sera of Anguilla japonica immunized with Edwardsiella tarda FPU 347 and characterized. Analysis of the purified IgM on sodium dodecyl sulfate-polyacrylamide gels (SDS-PAGE) under reducing and non-reducing conditions revealed that the eel IgM was a tetrameric protein with a molecular weight of 790,000; it contained an equimolar heavy chain and light chain with molecular weights of 72,000 and 25,000, respectively. While the N-terminal sequence of the heavy chain, VELTQPGSMVLKPGQSLTI, showed similarity to the variable regions of those of teleost fishes Igs, the N-terminal sequence of the light chain, DIVLTQSPAVQSVQLGDT, was similar to the variable regions of chondrostei and mammalian kappa chains. Lectin-binding assays showed that the binding of concanavalin A (Con A) to the Japanese eel IgM heavy chain was competitively inhibited by D-mannose and could be abolished by alpha-mannosidase treatment indicating the presence on the heavy chain of oligosaccharides, whose terminal were a bound mannoses. The average IgM concentration in the sera of the healthy eels was 3.4 mg ml(-1); it amounted to 10.3% of the total serum protein.
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PMID:Characterization of Japanese eel immunoglobulin M and its level in serum. 1128 Dec 70

A search of the yeast Saccharomyces cerevisiae genome has revealed an open reading frame, YNL275w, which encodes a 576-amino acid protein that shows sequence similarity to the family of mammalian Cl-/HCO3- anion exchangers and Na+/HCO3- cotransporters. This yeast protein also has a very similar hydropathy profile to the mammalian HCO3- transporters, indicating a similar membrane topology and structure. A V5 epitope and His6-tagged version of Ynl275wp was expressed in yeast and was localized to the plasma membrane by subcellular fractionation and immunofluorescence labeling. The protein was purified by nickel affinity chromatography and was found not to be N-glycosylated. The protein's mobility on SDS-PAGE gels was not altered by treatment with N-glycanase F, alpha-mannosidase, or by mutation of each of the five consensus N-glycosylation sites. The protein did not bind to concanavalin A by lectin blotting or lectin affinity chromatography. The expressed protein bound specifically to a stilbene disulfonate inhibitor resin (SITS-Affi-Gel), and this binding could be competed by certain anions (HCO3-, Cl-, NO3-, and I-) but not by others (SO4(2-) and PO4(3-)). These results suggest that the yeast gene YNL275w encodes a nonglycosylated anion transport protein, localized to the plasma membrane.
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PMID:Expression and characterization of the anion transporter homologue YNL275w in Saccharomyces cerevisiae. 1140 25

This study attempts to isolate and characterize West Nile virus-binding molecules on the plasma membrane of Vero and murine neuroblastoma cells that is responsible for virus entry. Pretreatment of Vero cells with proteases, glycosidases (endoglycosidase H, alpha-mannosidase), and sodium periodate strongly inhibited West Nile virus infection, whereas treatments with phospholipases and heparinases had no effect. The virus overlay protein blot detected a 105-kDa molecule on the plasma membrane extract of Vero and murine neuroblastoma cells that bind to WN virus. Treatment of the 105-kDa molecules with beta-mercaptoethanol resulted in the virus binding to a series of lower molecular weight bands ranging from 30 to 40 kDa. The disruption of disulfide-linked subunits did not affect virus binding. N-linked sugars with mannose residues on the 105-kDa membrane proteins were found to be important in virus binding. Specific antibodies against the 105-kDa glycoprotein were highly effective in blocking virus entry. These results strongly supported the possibility that the 105-kDa protease-sensitive glycoprotein with complex N-linked sugars could be the putative receptor for WN virus.
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PMID:Characterization of a 105-kDa plasma membrane associated glycoprotein that is involved in West Nile virus binding and infection. 1291 50

Locoweed poisoning occurs when livestock consume swainsonine-containing Astragalus and Oxytropis species over several weeks. Although the clinical and histologic changes of poisoning have been described, the dose or duration of swainsonine ingestion that results in significant or irreversible damage is not known. The purpose of this research was to document the swainsonine doses that produce clinical intoxication and histologic lesions. Twenty-one mixed-breed wethers were dosed by gavage with ground Oxytropis sericea to obtain swainsonine doses of 0.0, 0.05, 0.1, 0.2, 0.4, 0.8, and 1.0 mg/kg/day for 30 days. Sheep receiving > or = 0.2 mg/kg gained less weight than controls. After 16 days, animals receiving > or = 0.4 mg/kg were depressed, reluctant to move, and did not eat their feed rations. All treatment groups had serum biochemical changes, including depressed alpha-mannosidase, increased aspartate aminotransferase and alkaline phosphatase, as well as sporadic changes in lactate dehydrogenase, sodium, chloride, magnesium, albumin, and osmolarity. Typical locoweed-induced cellular vacuolation was seen in the following tissues and swainsonine doses: exocrine pancreas at > or = 0.05 mg/kg; proximal convoluted renal and thyroid follicular epithelium at > or = 0.1 mg/kg; Purkinje's cells, Kupffer's cells, splenic and lymph node macrophages, and transitional epithelium of the urinary bladder at > or = 0.2 mg/kg; neurons of the basal ganglia, mesencephalon, and metencephalon at > or = 0.4 mg/kg; and cerebellar neurons and glia at > or = 0.8 mg/kg. Histologic lesions were generally found when tissue swainsonine concentrations were approximately 150 ng/g. Both the clinical and histologic lesions, especially cerebellar lesions are suggestive of neurologic dysfunction even at low daily swainsonine doses of 0.2 mg/kg, suggesting that prolonged locoweed exposure, even at low doses, results in significant production losses as well as histologic and functional damage.
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PMID:Dose response of sheep poisoned with locoweed (Oxytropis sericea). 1296 59

The gene encoding the 45/47 kDa glycoprotein (Rv1860) of Mycobacterium tuberculosis was expressed in Streptomyces lividans under its own promoter and under the thiostrepton-inducible Streptomyces promoter PtipA. The recombinant protein was released into the culture medium and, like the native protein, migrated as a double band at 45 and 47 kDa in sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) gels. However, in contrast to the native protein, only the 47-kDa recombinant protein could be labeled with concanavalin A (ConA). Carbohydrate digestion with jack bean alpha-D-mannosidase resulted in a reduction in the molecular mass of the recombinant protein upper band and completely eliminated ConA binding. Two-dimensional gel electrophoresis revealed only one isoelectric point for the recombinant protein. Comparative fingerprinting analysis of the individually purified upper and lower recombinant protein bands, treated under the same conditions with specific proteases, resulted in similar peptide patterns, and the peptides had the same N-terminal sequence, suggesting that migration of the recombinant protein as two bands in SDS-PAGE gels could be due to differences in glycosylation. Mass spectrometry analysis of the recombinant protein indicated that as in native protein, both the N-terminal and C-terminal domains of the recombinant protein are glycosylated. Furthermore, it was determined that antibodies of human tuberculosis patients reacted mainly against the carbohydrate residues of the glycoprotein. Altogether, these observations show that expression of genes for mycobacterial antigens in S. lividans is very useful for elucidation of the functional role and molecular mechanisms of glycosylation in bacteria.
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PMID:Expression, secretion, and glycosylation of the 45- and 47-kDa glycoprotein of Mycobacterium tuberculosis in Streptomyces lividans. 1476 42

Enzymatic transglycosylation using p-nitrophenyl alpha-D-rhamnopyranoside as the glycosyl donor and 6equiv of ethyl 1-thio-alpha-D-rhamnopyranoside as the glycosyl acceptor yielded a D-rhamnooligosaccharide derivative. The reaction was catalyzed by jack bean alpha-mannosidase in a 1:1 (v/v) mixture of 0.1 M sodium citrate buffer (pH4.5)-MeCN at 25 degrees C. The enzyme exhibited high catalytic activity for the reaction, to afford in 32.1% isolated yield (based on donor substrate) ethyl alpha-D-rhamnopyranosyl-(1-->2)-1-thio-alpha-D-rhamnopyranoside, which is a derivative of the common oligosaccharide unit of the antigenic lipopolysaccharides from Pseudomonas.
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PMID:alpha-Mannosidase-catalyzed synthesis of a (1-->2)-alpha-D-rhamnodisaccharide derivative. 1511 80


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