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:3.1.3.1 (alkaline phosphatase)
47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The nonspecific alkaline phosphatase of yeast (Saccharomyces strain 1710) has been purified by ion exchange, hydrophobic, and affinity chromatography. This vacuolar enzyme has a molecular weight of 130,000 and is composed of subunits (probably of 66,000 molecular weight). It also has a small quantity of covalently associated carbohydrate; hydrolysis yielded mannose and glucosamine. The endo-beta-N-acetylglucosaminidase of Streptomyces plicatus released carbohydrate indicating that the latter was attached to protein through an N-acetylglucosaminylasparginyl bond. Synthesis of active alkaline phosphatase by yeast protoplasts is not depressed by tunicamycin, an inhibitor of dolichol-mediated protein glycosylation. Unlike the enzyme normally produced, the alkaline phosphatase which is formed in the presence of the antibiotic does not interact with concanavalin A and, therefore is deficient in or lacking carbohydrate. We infer that there is no regulatory link in yeast between the glycosylation of a protein and its synthesis. The fact that other Asn-GlcNAc-type glycoprotein enzymes of yeast such as acid phosphatase are not produced in their active forms by tunicamycin-treated protoplasts may mean that, as unglycosylated proteins, they cannot be correctly folded or processed. Protoplasts derepressed for phosphatase production contained substantial amounts of a second alkaline phosphatase which differed from the purified enzyme in substrate specificity, sensitivity to calcium, and reactivity with concanavalin A.
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PMID:Glycoprotein nature of yeast alkaline phosphatase. Formation of active enzyme in the presence of tunicamycin. 50 Jun 84

Ligand binding activity of intrinsic factor-cobalamin receptor (IFCR) was determined in homogenates and isolated brush-border membranes (BBM) of ileum and kidney from dogs exhibiting simple autosomal recessive inheritance of selective cobalamin malabsorption (Fyfe, J. C., Giger, U., Hall, C. A., Jezyk, P. F., Klumpp, S. A., Levine, J. S., and Patterson, D. F. (1991) Pediatr. Res. 29, 24-31). IFCR activity of affected dog ileal homogenates was 3-4-fold higher than normal whereas IFCR activity in affected dog kidney homogenates was one-tenth of normal. The recovery of IFCR activity in the BBM of ileum and renal cortex of affected dogs was 30- and 20-fold less than normal, respectively. The dissociation constant (Kd) for intrinsic factor-cobalamin was similar in BBM of both tissues and was the same in affected and normal dogs. In the affected dog ileal BBM, activities of alkaline phosphatase and sucrase-isomaltase and vesicular transport of glucose and Na(+)-taurocholate were normal. Immunoblots showed no IFCR cross-reactive material in the ileal or renal BBM of affected dogs. IFCR purified by affinity chromatography from kidney of both normal and affected dogs had an Mr = 230,000. However, amino acid analysis revealed that the affected dog IFCR had more lysine than the normal, and protease cleavage of the purified IFCRs revealed different peptide maps. Asparagine-linked oligosaccharides of both proteins were sensitive to peptide N-glycosidase F cleavage, but only the affected dog IFCR was endoglycosidase H sensitive. These results suggest that cobalamin malabsorption in this canine family is caused by inefficient BBM expression of IFCR due to a mutation of IFCR and its retention in an early biosynthetic compartment.
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PMID:Defective brush-border expression of intrinsic factor-cobalamin receptor in canine inherited intestinal cobalamin malabsorption. 199 30

Electron microscopic observations showed that the fungal metabolite brefeldin A caused disassembly of the Golgi complex in human choriocarcinoma cells and accumulation of alkaline phosphatase (ALP) in the endoplasmic reticulum (ER) and nuclear envelope, where ALP was not apparently detectable in control cells. Pulse/chase experiments with [35S]methionine demonstrated that in the control cells, ALP synthesized as a 63-kDa precursor form was rapidly converted to a 66-kDa form, by processing of its N-linked oligosaccharides from the high-mannose type to the complex type, which was expressed on the cell surface after 30 min of chase. In contrast, in the brefeldin-A-treated cells the precursor was gradually converted to a 65-kDa form, slightly smaller than the control mature form, which was not expressed on the cell surface even after a prolonged time of chase. Kinetics of the ALP processing in the brefeldin-A-treated cells demonstrated that the precursor was initially converted to an intermediate form, partially sensitive to endo-beta-N-acetylglucosaminidase H (endo H), then to an endo-H-resistant 65-kDa form. In addition, this form was found to be sensitive to neuraminidase digestion, though its sialylation was not so complete as that of the control mature form. Taken together, these results suggest that under disassembly of the Golgi complex caused by brefeldin A, oligosaccharide-processing enzymes including sialyltransferase, an enzyme in the trans Golgi cisterna(e) and/or the trans Golgi network, might be redistributed into the ER and involved in processing of the oligosaccharides of ALP accumulating there.
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PMID:Intracellular accumulation and oligosaccharide processing of alkaline phosphatase under disassembly of the Golgi complex caused by brefeldin A. 226 2

The role of N-linked oligosaccharide side chains in the biogenesis and function of Na+-coupled transporters in renal luminal brush-border membrane (BBM) is not known. We examined the question of how in vivo inhibition by alkaloid swainsonine of alpha-mannosidase, a key enzyme in processing of glycoproteins in the Golgi apparatus, affects Na+/H+ antiport and Na+/Pi symport as well as activities of other transporters and enzymes in rat renal BBM. Administration of swainsonine to thyroparathyroidectomized rats, control or treated with 3,5,3'-triiodothyronine, markedly decreased the rate of Na+/H+ antiport, but had no effect on the rate of Na+/Pi symport across renal BBM vesicles (BBMV). Moreover, administration of swainsonine did not change activities of Na+ gradient, ([extravesicular Na+] greater than [intravesicular Na+])-dependent transport of D-glucose, L-proline, or the amiloride-insensitive 22Na+ uptake by BBMV; the activities of the BBM enzymes alkaline phosphatase, gamma-glutamyltransferase, or leucine aminopeptidase in BBMV were also not changed. The in vitro enzymatic deglycosylation of BBM by incubating freshly isolated BBMV with bacterial endoglycosidase F also resulted in a decreased rate of Na+/H+ antiport, but not Na+-coupled symports of Pi, L-proline, and D-glucose, or the activities of the BBM enzymes were not significantly affected. Similar incubation with endoglycosidase H was without effect on any of these parameters. Both the modification of BBMV glycoproteins by administration fo swainsonine in vivo as well as the in vitro incubation of BBMV with endoglycosidase F resulted in a decrease of the apparent Vmax of Na+/H+ antiport, but did not change the apparent Km of this antiporter for extravesicular Na+ and did not increase H+ conductance of BBM. Taken together, our findings suggest that intact N-linked oligosaccharide chains of the biantennary complex type in renal BBM glycoproteins are required, directly or indirectly, for the transport function of the Na+/H+ antiporter inserted into BBM of renal proximal tubules.
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PMID:Role of N-linked oligosaccharides in the transport activity of the Na+/H+ antiporter in rat renal brush-border membrane. 284 30

Arylsulfatase A was purified from human lung and human placenta to apparent homogeneity presented by electrophoresis in the absence and presence of sodium dodecyl sulfate. The enzyme from normal lung, placenta, and lung adenocarcinoma showed considerable charge heterogeneity when examined by isoelectrofocusing, with isoelectric point (pI) ranging from 5.1 to 4.6. The enzyme from adenocarcinoma was more heterogeneous and having more acidic components than the other enzyme. When the tumor enzyme was treated with exogenous sialidase, alkaline phosphatase, or endo-beta-N-acetylhexosaminidase H (endoglycosidase H), the acidic components of the enzyme shifted to the more alkaline region on the focussing gel. The banding pattern of the enzyme from normal tissues also changed to the more alkaline region when treated with exogenous hydrolase and showed almost the same pattern as hydrolase treated enzyme from adenocarcinoma. Combined treatment of the enzyme with endoglycosidase H and sialidase resulted in complete loss of the most acidic components to give the less acidic components with pI of 5.1.50. and 4.9. Cyclic AMP-dependent protein kinase could not phosphorylate the protein moiety of arylsulfatase A even after the enzyme was treated with alkaline phosphatase. When an acidic fraction of the endoglycosidase H sensitive oligosaccharides from arylsulfatase A was treated with phosphatase, the acidic oligosaccharide fraction lost the negative charge on QAE-Sephadex chromatography. These results strongly suggest that the charge heterogeneity of arylsulfatase A is due not only to sialylation but also to phosphorylation at the carbohydrate moiety of the enzyme, and that the extent of substitution by acidic groups, sialic acid residue and phosphate residue, is markedly increased in the tumor enzyme.
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PMID:[Studies on charge heterogeneity of arylsulfatase A from human lung cancer]. 286 24

Two PRL-like glycoprotein hormone complexes were purified from the medium of cultured mouse conceptuses from day 10 of pregnancy: mouse placental lactogen-I (mPL-I) (29-32K), and mPL-I (36.5-42K). Sodium dodecyl sulfate-gel electrophoresis revealed that mPL-I (36.5-42K) is a complex of five proteins with mol wt of 36.5K, 37.5K, 39K, 40.5K, and 42K. Deglycosylation with peptide: N-glycosidase F or trifluoromethanesulfonic acid produced a single 29K protein. mPL-I (36.5-42K) was also sensitive to neuraminidase, but not to endo-beta-N-acetylglucosaminidase H or bacterial alkaline phosphatase. The production of intermediates from partial digestion of mPL-I (36.5-42K) with endo-beta-N-acetylglucosaminidase F indicated the presence of multiple glycosylation sites. mPL-I (29-32K) is a complex of three proteins with mol wt of 29K, 30.5K, and 32K. Treatment with peptide:N-glycosidase F or trifluoromethanesulfonic acid reduced the mol wt of the 30.5K and 32K bands to 28K. The 30.5K band was sensitive to endo-beta-N-acetylglucosaminidase H and endo-beta-N-acetylglucosaminidase F, but the 32K band was not. Neither band was sensitive to neuraminidase or bacterial alkaline phosphatase. The 29K band was resistant to all chemical and enzymatic treatments and is probably not glycosylated or phosphorylated. In the nonreduced state, neither form of mPL-I showed an increase in mobility over that of its reduced counterpart on sodium dodecyl sulfate-gel electrophoresis, indicating that neither form of mPL-I contains the large disulfide loop common to hormones of the PRL family. After iodination, all component proteins of both forms of mPL-I were found to bind to day 17 pregnant mouse liver membranes and were displaceable by excess mPL-II. In a radioreceptor assay, 125I-labeled mPL-I (36.5-42K) was displaced by mPRL or mPL-II, but not by mGH. An antiserum to both forms of mPL-I was generated, and a RIA employing mPL-I (36.5-42K) as the standard and radioligand was developed. Dilutions of day 10 pregnant maternal mouse serum and placental homogenate and a partially purified fraction of mPL-I (29-32K) produced displacement curves parallel to that of mPL-I (36.5-42K) standard curve. Five micrograms of mPRL, mPL-II, or mGH or 10 microliter day 17 pregnant or male mouse serum did not displace the radioligand from the antibody. mPL-I (36.5-42K) was lactogenic, but it did not possess LH-like bioactivity.
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PMID:Purification and partial characterization of two prolactin-like glycoprotein hormone complexes from the midpregnant mouse conceptus. 303 95

We have studied the posttranslational modifications of the 52-kD protein, an estrogen-regulated autocrine mitogen secreted by several human breast cancer cells in culture (Westley, B., and H. Rochefort, 1980, Cell, 20:353-362). The secreted 52-kD protein was found to be phosphorylated mostly (94%) on high-mannose N-linked oligosaccharide chains, and mannose-6-phosphate signals were identified. The phosphate signal was totally removed by alkaline phosphatase hydrolysis. The secreted 52-kD protein was partly taken up by MCF7 cells via mannose-6-phosphate receptors and processed into 48- and 34-kD protein moieties as with lysosomal hydrolases. By electron microscopy, immunoperoxidase staining revealed most of the reactive proteins in lysosomes. After complete purification by immunoaffinity chromatography, we identified both the secreted 52-kD protein and its processed cellular forms as aspartic and acidic proteinases specifically inhibited by pepstatin. The 52-kD protease is secreted in breast cancer cells under its inactive proenzyme form, which can be autoactivated at acidic pH with a slight decrease of molecular mass. The enzyme of breast cancer cells, when compared with cathepsin D(s) of normal tissue, was found to be similar in molecular weight, enzymatic activities (inhibitors, substrates, specific activities), and immunoreactivity. However, the 52-kD protein and its cellular processed forms of breast cancer cells were totally sensitive to endo-beta-N-acetylglucosaminidase H (Endo H), whereas several cellular cathepsin D(s) of normal tissue were partially Endo H-resistant. This difference, in addition to others concerning tissue distribution, mitogenic activity and hormonal regulation, strongly suggests that the 52-kD cathepsin D-like enzyme of breast cancer cells is different from previously described cathepsin D(s). The 52-kD estrogen-induced lysosomal proteinase may have important functions in facilitating the mammary cancer cells to proliferate, migrate, and metastasize.
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PMID:Phosphorylation, glycosylation, and proteolytic activity of the 52-kD estrogen-induced protein secreted by MCF7 cells. 354 22

The major scrapie prion protein, designated PrP 27-30, exhibited both charge and size heterogeneity after purification from infected hamster brains. Eight or more discrete charge isomers of PrP 27-30 with isoelectric points ranging from approximately pH 4.6 to 7.9 were found by using non-equilibrium pH gradient electrophoresis in the first dimension followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis in the second dimension. The charge isomers were detected by silver staining as well as by radioiodination. The procedures used to disaggregate PrP 27-30 before electrophoresis in the first dimension do not appear to be responsible for the charge heterogeneity. However, heating PrP 27-30 to 100 degrees C for 15 min in 0.1 N NaOH or 0.1 N HCl resulted in modification of the protein and alteration of its electrophoretic pattern. A PrP 27-30 fragment (molecular weight, 17,100 to 21,900) obtained by cyanogen bromide cleavage also exhibited charge and size heterogeneity. Periodic acid-Schiff staining of PrP 27-30 electrophoresed into sodium dodecyl sulfate-polyacrylamide gels demonstrated that carbohydrate residues are attached to the protein. Digestion of PrP 27-30 with neuraminidase and endo-beta-N-acetylglucosaminidase H resulted in significant changes in the isoelectric pH of PrP 27-30 isomers, whereas digestion with alkaline phosphatase had no effect. Our results demonstrate that PrP 27-30 is a sialoglycoprotein; this is consistent with several properties of this protein and of the scrapie prion.
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PMID:Scrapie PrP 27-30 is a sialoglycoprotein. 391 76

beta-Glucuronidase from human maxillary sinus and lung cancers and from uninvolved tissues was studied. An elevation of beta-glucuronidase activity was observed in cancerous tissues as compared with the corresponding uninvolved tissues, and this increase was significant in adenocarcinoma and squamous cell carcinoma of the lung (p less than 0.01). beta-glucuronidase preparations purified from adenocarcinoma and large cell carcinoma of lung and from normal lung showed similar kinetic properties and antigenicity. beta-Glucuronidase from lung adenocarcinoma showed considerable negative charge heterogeneity in the pI range from 4.2 to 6.2 in an experiment involving isoelectric focusing on polyacrylamide gel. Similar charge heterogeneity was observed in the enzyme from lung large cell carcinoma. Upon treatment of the adenocarcinoma enzyme with exogenous alkaline phosphatase or endoglycosidase H, the heterogeneous variant forms of the tumor enzyme appeared to partly or completely lose their negative charge and to be converted into forms similar to those of the normal lung enzyme. An experiment on the labeling of beta-glucuronidase with [32P]-phosphoric acid provided further evidence that the acidic variants found in lung cancers are extensively phosphorylated forms of the enzyme.
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PMID:[beta-Glucuronidase in human maxillary sinus and lung cancers: elevation of activity level and appearance of phosphorylated variant forms]. 609 43

Lysosomal arylsulfatases A and B of peripheral leukocytes from patients with chronic myelogenous leukemia and from healthy subjects were studied. Two enzyme activities of leukemia cells were significantly higher than those of cells from healthy subjects, irrespective of total and differential counts of leukemic cells. Upon anion-exchange chromatography, the arylsulfatases of chronic myelogenous leukemia cells and normal leukocytes were separated into the basic B enzyme and its anionic variant (B1) and A enzyme. However, the amount of B1 enzyme relative to B enzyme or the activity ratio of B1 enzyme to total arylsulfatase B (B + B1) was higher in chronic myelogenous leukemia cells than in normal cells. The anionic property of the enzyme was found to be due to phosphate groups bound to the carbohydrate moiety of the arylsulfatase, based on the following results. When B1 enzyme was treated with alkaline phosphatase followed by isoelectric focusing, it was changed to a less anionic enzyme with heterogeneous components which are ascribed to phosphodiester groups linked to the heterogeneous carbohydrate moiety of the enzyme; no effect was observed by sialidase treatment. Upon treatment of B1 enzyme with endo-beta-N-acetylglucosaminidase H, which cleaves sugar chains of a high mannose type in glycoproteins, the anionic heterogeneous components were converted to the basic component similar to B enzyme. From our present and previous observations, it can be concluded that the increase of phosphorylated forms of the lysosomal hydrolase represents one characteristic of rapidly proliferating neoplastic cells.
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PMID:Lysosomal arylsulfatases of human leukocytes: increment of phosphorylated B variants in chronic myelogenous leukemia. 613 78


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