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)

Calf pancreas microsomes incorporated radioactive D-mannose from GDP-D-[14C]mannose into lipid-bound oligosaccharides extracted with chloroform/methanol/water (10/10/2.5, v/v). Several products, which probably differed in the size of the oligosaccharide moiety, were labeled. These could be partially resolved by thin layer chromatography and DEAE-cellulose chromatography. The labeled lipid-bound oligosaccharides were retained on DEAE-cellulose more strongly than synthetic dolichyl alpha-D-[14C]mannopyranosyl phosphate. They were stable to mild alkali, but labile to acid and hot alkali. Acid treatment yielded a neutral 14C-labeled oligosaccharide fraction which was estimated by gel filtration to have a minimum of 8 monosaccharide residues. Hot alkali treatment yielded a mixture of neutral and acidic 14C-labeled oligosaccharides which could be transformed into neutral products by alkaline phosphatase. The D-[14C]mannose residues were alpha-linked at the nonreducing terminus of the oligosaccharides since they could be removed completely with alpha-mannosidase. Most of the D-[14C]mannose-labeled oligosaccharides were retained on concanavalin A Sepharose and eluted with methyl alpha-D-mannopyranoside. Pancreatic dolichyl beta-D-[14C]mannopyranosyl phosphate incubated with calf pancreas microsomes in the presence of sodium taurocholate was efficiently utilized as donor of alpha-D-mannosyl residues in lipid-bound oligosaccharides. The products formed from dolichyl beta-D-[14C]mannopyranosyl phosphate were identical with those formed from GDP-D-[14C]mannose, and evidence was obtained to show that the dolichyl beta-D-[14C]mannopyranosyl phosphate was serving as donor without prior conversion to GDP-D-[14C]mannose. Transfer of mannose from dolichyl beta-D-[14C]mannopyranosyl phosphate to lipid-bound oligosaccharides took place at a pH optimum of 7.3, whereas transfer to the precipitate containing glycoproteins was greatest at pH 6.0 in Tris/maleate buffer. The addition of divalent cation was not required, but low concentrations of EDTA were extremely inhibitory. The carbohydrate composition of the lipid-bound oligosaccharides of microsomal membranes was investigated by gas-liquid chromatography and by reduction with sodium borotritide. A heterogeneous mixture of oligosaccharides containing N-acetyl-D-glucosamine, D-mannose, and D-glucose varying in proportions from approximately 1/2.5/0.5 to 1/5/1.5 was obtained with glucosamine at the reducing end. Acid treatment of the lipid-bound oligosaccharide fraction yielded dolichyl pyrophosphate, suggesting that at least some of the oligosaccharides were linked to dolichol through a pyrophosphate group.
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PMID:Mannosyltransferase activity in calf pancreas microsomes. Formation of 14C-labeled lipid-linked oligosaccharides from GDP-D-[14C]mannose and pancreatic dolichyl beta-D-[14C]mannopyranosyl phosphate. 1 65

One component, the i form, of acid phosphatase (orthophosphoric-monoester phosphohydrolase (acid optimum), EC 3.1.3.2) produced by Aspergillus niger was purified from the mycelial extract. The purified enzyme was homogenous on Sephadex G-200 gel filtration, disc electrophoresis and heat inactivation. The purified enzyme was studied and the following results were obtained: 1. The enzyme catalyzed the hydrolysis of a wide variety of phosphomonoesters, but not that of bis(p-nitrophenyl)phosphate, adenosine 3',5'-cyclic monophosphate, fructose 1,6-diphosphate, adenosine 5'-diphosphate or adenosine 5'-triphosphate. 2. Fluoride, orthophosphate, arsenate, borate, molybdate and (+)-tartrate acted as inhibitors. This enzyme was inactivated by N-bromosuccinimide and 2-hydroxy-5-nitrobenzyl bromide, and was not affected by p-chloromercuribenzoate, N-acetylimidazole, p-diazobenzenesulfonic acid and tetranitromethane. From these results, tryptophan was estimated to play an important role in the enzyme activity. 3. The apparent molecular weight was 310000 by Sephadex G-200 gel filtration. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate suggested that the molecular weight of the subunit was approximately 89000. 4. The purified enzyme contained 29% carbohydrate consisting of glucosamine, mannose and galactose. The amino acid composition of this enzyme was not specific compared with other known acid phosphatases.
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PMID:Purification and properties of one component of acid phosphatase produced by Aspergillus niger. 1 43

Activities of the enzymes glutamine synthetase (EC 6.3.1.2.), glucosamine 6-phosphate acetyltransferase (EC 2.3.1.4.), uridine 5'-diphosphate (UDP)-N-acetylglucosamine pyrophosphorylase (EC 2.7.23.), UDP-N-acetylglucosamine 4-epimerase (EC 5.1.3.7.), fructose 1,6-diphosphate phosphatase (EC 3.13.11.), L-glutamine-fructose 6-phosphate transamidase (EC 5.3.1.19.), alkaline phosphatase (EC 3.1.3.1.), and malic dehydrogenase (EC 1.1.1.37) were assayed in partially purified extracts prepared at different stages of myxospore formation and germination in liquid cultures of Myxococcus xanthus. The specific activities of the first six of these enzymes increased 4.5- to 7.5-fold after 2 h of induction with 0.5 M glycerol or 0.2 M dimethyl sulfoxide. The increase in specific activities of these six enzymes was not observed in a mutant unable to be induced with glycerol. During the first 2 to 4 h of induction and during the first hour of germination, the level of these enzymes decreased to the level characteristic of vegetative cells. It is suggested that the six enzymes are responsible for the increased conversion of fructose 1,6-diphosphate to UDP-N-acetylgalactosamine, the major precursor of the myxospore coat.
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PMID:Myxospore coat synthesis in Myxococcus xanthus: enzymes associated with uridine 5'-diphosphate-N-acetylgalactosamine formation during myxospore development. 1 17

The perichondrial ossification groove of Ranvier, a circumferential groove in the periphery of the epiphyseal cartilage, was studied in rabbits whose ages ranged from one week to eight months using light and electron microscopy, autoradiography after labeling with 3H-thymidine, 3H-proline, and 3H-glucosamine, and histochemical staining for proteoglycans and alkaline phosphatase. By these methods, three groups of cells were identified within the groove: 1. A group of densely packed cells deep in the groove, which are the progenitor cells for the osteoblasts that form the bone bark, a cuff of bone surrounding the epiphyseal growth-plate region and the adjacent part of the metaphysis. 2. A group of more widely dispersed, relatively undifferentiated mesenchymal cells and fibroblasts, some of which are chondroblast precursors that probably contribute to appositional chondrogenesis and growth in width of the epiphyseal cartilage. 3. Fibroblasts and fibrocytes among sheets of highly oriented and organized collagen fibers which form a fibrous layer that is continuous with the outer fibrous layer of the periosteum and with the perichondrium. This layer also sends fibers into the epiphyseal cartilage and anchors the periosteum firmly to the epiphyses as bone growth proceeds.
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PMID:Organization and cellular biology of the perichondrial ossification groove of ranvier: a morphological study in rabbits. 7 Dec 99

The structure of lipopolysaccharide from a heptose-less mutant of Escherichia coli K-12 has been investigated. Lipopolysaccharide isolated from 32P-labeled cells was treated with mild alkali to yield two separable components: [OH-LPS]-I (approximately 70%) and [OH-LPS]-II (approximately 30%). Mild acidic treatment of [OH-LPS]-I gave mainly a product which was identified as (4-O-phosphoryl-N-beta-hydroxymyristyl-D-glucosaminyl)-beta(1 leads to 6)-N-beta-hydroxymyristyl-D-glucosamine 1-phosphate (Compound I). Further acidic hydrolysis of both [OH-LPS]-I and [OH-LPS]-II yielded as the main product (4-O-phosphoryl-N-beta-hydroxymyristyl-D-glucosaminyl)-beta(1 leads to 6)-N-beta-hydroxymyristyl-D-glucosamine (Compound II). The structures of the above products were deduced by a combination of compositional analyses, sensitivity to phosphomonoesterase, rates of hydrolysis of the phosphate groups and alkali-catalyzed beta elimination of the phosphate residues following appropriate oxidation of hydroxyl groups. These studies together with work reported in the accompanying papers have led to the identification of two species of lipopolysaccharide in the E. coli strain both of which contain a single glucosamine dissacharide unit but differ in having monosubstituted phosphate or pyrophosphate groups at the glycosidic position. Each species of lipopolysaccharide also appeared to be heterogeneous with respect to the number of esterified fatty acyl groups.
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PMID:Structure of the lipopolysaccharide from an Escherichia coli heptose-less mutant. I. Chemical degradations and identification of products. 22 86

The effect of intestinal bacterial over-growth on brush border hydrolases and brush border glycoproteins was studied in nonoperated control rats, control rats with surgically introduced jejunal self-emptying blind loops, and rats with surgically introduced jejunal self-filling blind loops. Data were analyzed from blind loop segments, segments above and below the blind loops, and three corresponding segments in the nonoperated controls. Rats with self-filling blind loops had significantly greater fat excretion than controls and exhibited significantly lower conjugated:free bile salt ratios in all three segments. Maltase, sucrase, and lactase activities were significantly reduced in homogenates and isolated brush borders from the self-filling blind loop, but alkaline phosphatase was not affected. The relative degradation rate of homogenate and brush border glycoproteins was assessed by a double-isotope technique involving the injection of d-[6-(3)H]glucosamine 3 h and d-[U-(14)C]glucosamine 19 h before sacrifice, and recorded as a (3)H:(14)C ratio. The relative degradation rate in both homogenate and brush border fractions was significantly greater in most segments from rats with self-filling blind loops. In the upper and blind loop segments from rats with self-filling blind loops, the (3)H:(14)C ratios were higher in the brush border membrane than in the corresponding homogenates, indicating that the increased rates of degradation primarily involve membrane glycoproteins. Incorporation of d-[6-(3)H]glucosamine by brush border glycoproteins was not reduced in rats with self-filling blind loops, suggesting that glycoprotein synthesis was not affected. Polyacrylamide gel electrophoresis of brush border glycoproteins from the contaminated segments indicated that the large molecular weight glycoproteins, which include many of the surface hydrolases, were degraded most rapidly. Brush border maltase, isolated by immunoprecipitation, had (3)H:(14)C ratios characteristic of the most rapidly degraded glycoproteins. The results indicate that bacteria enhance the destruction of intestinal surface glycoproteins including disaccharidases. Since alkaline phosphatase, a glycoprotein, is not affected, the destruction is selective and presumably involves only the most exposed membrane components.
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PMID:Pathogenesis of mucosal injury in the blind loop syndrome. Brush border enzyme activity and glycoprotein degradation. 41 Aug 30

Turnover in organ culture of human small intestinal membrane glycoproteins was measured by the pulse-chase technique, using 14C-glucosamine, 14C-fucose or 14C-leucine as tracers. Apparently, low degradation rates were found for the major high-molecular-weight proteins which co-migrated on SDS-polyacrylamide gels with maltase-glucoamylase, lactase-phlorizin-hydrolase and sucrase-isomaltase enzymic activities. In contrast, an unidentified glycoprotein appearing on gels next to alkaline phosphatase exhibited a higher degradation rate with an apparent half-life of about 30 h, this being similar to the half-life of total glycoprotein as measured in mucosal homogenates. The results obtained with the pulse-chase technique were confirmed by double isotope experiments using 14C-leucine and 3H-leucine as tracers. These findings indicate that in organ culture there is a low basic turnover of human intestinal membrane glycoproteins which co-migrate on gels with known glycosidase enzymic activities.
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PMID:Turnover studies of human intestinal brush border membrane glycoproteins in organ culture. 45 41

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

Extrahepatic bile flow obstruction is followed by a several-fold increase in alkaline phosphatase activity in the liver. This activity passes into the blood. The increase in the activity of the enzyme in the liver can be prevented by inhibitors of RNA and protein synthesis. Inducible alkaline phosphatase was purified from rat liver and 1,000-fold purification was achieved. The incorporation of labbelled precursors (14C amino acids and 14C glucosamine) into the liver alkaline phosphatase was evaluated. No significant difference were found between specific alkaline phosphatase activities and specific radioactivities in the control rats and rats with 7.30 h after bile duct obstruction. The incorporation of 14C-amino acids into the total liver proteins was 20% lower in rats with cholestasis than in the control group. The results are evidence that the liver is the source of elevated alkaline phosphatase activity in serum in cholestasis, and that the production of alkaline phosphatase in the liver is prevented by inhibitors of RNA a protein synthesis. However, the enzyme might be synthesized before the 14C-labelled precursors were applied.
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PMID:Experimental study on the mechanism of hyperphosphatasaemia in bile flow obstruction. 61 64

The incorporation of [14C]glucosamine into brush border glycoproteins by human small intestinal mucosa in organ culture has been investigated. The experiments were based on the observations that (1) isolated brush border membrane fragments from cultured explants showed an unchanged pattern of protein bands and brush border enzyme activities on sodium dodecyl sulfate/polyacrylamide gels after electrophoresis and (2) the rate of overall [14C]glucosamine incorporation measured in the tissue homogenate remained constant up to 48 h. After 24 h of culture, the radioactivity peaks on gels due to incorporation of [14C]glucosamine were found exclusively in the high molecular weight region and corresponded to protein bands identified as maltase-glucoamylase, lactase, sucrase-isomaltase, enterokinase and alkaline phosphatase. Enzymatic activity could not be assigned to the three remaining labelled bands. Most of these glycoproteins were already labelled after 5 h. Newly glycosylated brush border enzymes remained predominantly associated with the brush border membrane of intact cells with little release into the medium up to 24 h.
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PMID:Biosynthesis of brush border glycoproteins by human small intestinal mucosa in organ culture. 88 74


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