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)

To investigate the functional stages of osteoclasts, the ultrastructural histochemical distribution of the lysosomal enzymes [acid phosphatase (tartrate-sensitive) and neutral phosphatase], the plasma membrane enzymes [alkaline phosphatase, Ca(++)-ATPase, and alkaline ouabain-insensitive p-nitrophenylphosphatase (alkaline p-NPPase)], and the mitochondrial enzyme (cytochrome C oxidase) was evaluated in the chicken tibial metaphysis. Both active-appearing and detached (resting) osteoclasts were studied. Serial sectioning was used to identify detached osteoclasts which were present in the perivascular space. The ultrastructure of detached osteoclasts was similar to that of active osteoclasts, except for the lack of a ruffled border and clear zone, and an altered distribution pattern of small vesicles. Small vesicles were uniformly distributed in the cytoplasm of resting osteoclasts, whereas they were concentrated beneath the ruffled border of active osteoclasts. Alkaline p-NPPase, a marker enzyme for the basal ruffled border, was also apparent on the membrane of small vesicles. However, the vesicles did not possess Ca(++)-ATPase, a marker enzyme for the apical plasma membrane. These findings support the concept that small vesicles serve as a membrane reservoir for the ruffled border membrane. Pre-osteoclasts contained abundant mitochondria and lysosomes, prominent Golgi complexes, moderately developed endoplasmic reticulum, and lacked small vesicles. Pre-osteoclasts appear to fuse with osteoclasts which are attached to the bone surface, but not with detached osteoclasts. The small vesicles, from which the ruffled border arises, are absent from pre-osteoclasts, suggesting that they develop after fusion with pre-existing osteoclasts or after attachment to the bone surface. Alkaline p-NPPase appears to be a marker for differentiation of pre-osteoclasts to mature osteoclasts.
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PMID:Characterization of the functional stages of osteoclasts by enzyme histochemistry and electron microscopy. 166 72

Formylmethanofuran dehydrogenase from Methanobacterium thermoautotrophicum was purified to apparent homogeneity and found to contain per mol (apparent molecular mass 110 kDa) 0.6 mol molybdenum, 4 mol non-heme iron, 4 mol acid-labile sulfur, and in addition, 0.7 mol of a pterin-containing co-factor (apparent molecular mass 800 Da) which has been characterized. The pterin material was extracted after alkylation by iodoacetamide and the extract subjected to HPLC on Lichrospher 100 RP-18. Three pterin compounds were resolved. On the basis of their UV/visible spectra and of the products formed after cleavage by nucleotide pyrophosphatase and alkaline phosphatase they were identified as the [di(carboxamidomethyl)]-derivatives of molybdopterin guanine dinucleotide (MGD), of molybdopterin adenine dinucleotide (MAD), and of molybdopterin hypoxanthine dinucleotide (MHD). The three pterin dinucleotides were present in the proportions 1:0.4:0.1.
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PMID:Molybdopterin adenine dinucleotide and molybdopterin hypoxanthine dinucleotide in formylmethanofuran dehydrogenase from Methanobacterium thermoautotrophicum (Marburg). 191 87

3'-Azido-2',3'-dideoxyuridine (AzdU, CS-87) is a potent inhibitor of human immunodeficiency virus replication in human peripheral blood mononuclear cells (PBMC) with limited toxicity for human bone marrow cells (BMC). In the present study, metabolism of AzdU was investigated in human PBMC and BMC after exposure of cells to 2 or 10 microM [3H]AzdU. 3'-Azido-2',3'-dideoxyuridine-5'-monophosphate (AzdU-MP) was the predominant metabolite, representing approximately 55 to 65% of intracellular radioactivity in both PBMC and BMC at all times. The AzdU-5'-diphosphate and -5'-triphosphate intracellular levels were 10- to 100-fold lower than the AzdU-MP levels and, of note, AzdU-5'-triphosphate was not detected in human BMC. Using anion exchange chromatography, a new peak of radioactivity, distinct from any known anabolites, was detected. This chromatographic peak was found to be resistant to alkaline phosphatase but was hydrolyzed by 5'-phosphodiesterase, yielding AzdU-MP. Incubation of [3H]AzdU and D-[1-14C]glucose in PBMC and BMC produced a double-labeled peak with the same retention time as the anabolite, suggesting formation of a hexose derivative of AzdU. A novel high performance liquid chromatography method was developed that allowed for the separation of nucleosides, nucleotides, and carbohydrate derivatives thereof. Using this highly specific method, the putative AzdU-hexose actually was separated into two chromatographic peaks. These novel metabolites were identified as 3'-azido-2',3'-dideoxyuridine-5'-O-diphosphoglucose and 3'-azido-2',3'-dideoxyuridine-5'-O-diphospho-N-acetylglucosamine. Following 48 hr of incubation with [3H] AzdU, as much as 20 and 30% of these AzdU metabolites accumulated in PBMC and BMC, respectively. When AzdU was removed from the cell cultures, intracellular AzdU diphosphohexose concentrations decayed in a monophasic manner, with an elimination half-life of 14.3 hr. By 48 hr, levels of 0.3 pmol/10(6) cells were still detected, reflecting a gradual anabolism of these metabolites. Elimination of AzdU-MP and AzdU-5'-diphosphate was characterized by a two-phase process, with a short initial half-life of 0.83 and 0.24 hr and a long terminal half-life of 14.10 and 8.24 hr, respectively. Similar diphosphohexoses of deoxyuridine (dUrd) were also detected in human PBMC and BMC after exposure to [3H]dUrd, suggesting that dUrd derivatives are metabolized in a similar manner. In summary, the discovery of novel metabolic pathways for dUrd analogs demonstrates that AzdU has unique metabolic features that may contribute to the low toxicity of this anti-HIV agent in human BMC and also affect its mechanism of action.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Cellular metabolism of 3'-azido-2',3'-dideoxyuridine with formation of 5'-O-diphosphohexose derivatives by previously unrecognized metabolic pathways for 2'-deoxyuridine analogs. 225 Jun 66

The molybdenum cofactor of formylmethanofuran dehydrogenase from methanol-grown Methanosarcina barkeri was isolated as the [di(carboxamidomethyl)]-derivative. The alkylated factor showed an absorption spectrum and chemical properties identical to those recently reported for the molybdenum cofactor of dimethyl sulfoxide reductase from Rhodobacter sphaeroides. By treatment with nucleotide pyrophosphatase the factor was resolved into two components, which were identified as [di(carboxamidomethyl)]-molybdopterin and GMP by their absorption spectra, their retention times on Lichrospher RP-18, and by their conversion to dephospho-[di(carboxamidomethyl)]-molybdopterin and guanosine, respectively, in the presence of alkaline phosphatase. The GMP-moiety was sensitive to periodate, identifying it as the 5'-isomer. These results demonstrate that the molybdenum cofactor isolated from formylmethanofuran dehydrogenase contains the phosphoric anhydride of molybdopterin and 5'-GMP.
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PMID:The molybdenum cofactor of formylmethanofuran dehydrogenase from Methanosarcina barkeri is a molybdopterin guanine dinucleotide. 225 82

The pterin cofactor (bactopterin) in the molybdoenzyme CO dehydrogenase isolated from Pseudomonas carboxydoflava has previously been shown to differ from molybdopterin in molecular mass, phosphate content, stability, and other properties, implying a novel structure. The structure of the CO dehydrogenase pterin has been investigated in the present studies by alkylation and isolation of the carboxamidomethyl derivative. The alkylated pterin was identified as [di-(carboxamidomethyl)]molybdopterin cytosine dinucleotide on the basis of its absorption properties and by degradation with nucleotide pyrophosphatase yielding carboxamidomethylmolybdopterin and CMP. Further treatment of these products with alkaline phosphatase produced species with absorption and chromatographic properties identical to those of the corresponding dephospho compounds. Molybdopterin cytosine dinucleotide is the second molybdopterin variant to be structurally characterized. The fact that molybdopterin cytosine dinucleotide and molybdopterin guanine dinucleotide contain molybdopterin in their structure shows that the pterin moiety, with its unique dithiolene-containing sidechain, is a structural element which is common to the organic portion of the molybdenum cofactors of many molybdoenzymes.
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PMID:Isolation and characterization of a second molybdopterin dinucleotide: molybdopterin cytosine dinucleotide. 227 62

The nature of molybdenum cofactor in the bacterial enzyme dimethyl sulfoxide reductase has been investigated by application of alkylation conditions that convert the molybdenum cofactor in chicken liver sulfite oxidase and milk xanthine oxidase to the stable, well-characterized derivative [di(carboxamidomethyl)]molybdopterin. The alkylated pterin obtained from dimethyl sulfoxide reductase was shown to be a modified form of alkylated molybdopterin with increased absorption in the 250-nm region of the spectrum and altered chromatographic behavior. The complex alkylated pterin was resolved into two components by treatment with nucleotide pyrophosphatase. These were identified as di(carboxamidomethyl)molybdopterin and GMP by their absorption spectra, coelution with standard compounds, and by further degradation by alkaline phosphatase to dephospho [di(carboxamidomethyl)]molybdopterin and guanosine. The GMP moiety was sensitive to periodate, identifying it as the 5' isomer. Chemical analysis of the intact alkylated pterin showed the presence of two phosphate residues per pterin. These results established that the pterin isolated from dimethyl sulfoxide reductase contains the phosphoric anhydride of molybdopterin and 5'-GMP, which is designated molybdopterin guanine dinucleotide.
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PMID:Molybdopterin guanine dinucleotide: a modified form of molybdopterin identified in the molybdenum cofactor of dimethyl sulfoxide reductase from Rhodobacter sphaeroides forma specialis denitrificans. 232 78

NADH oxidase activity has been detected at the ultrastructural level using cerium ions to trap H2O2 generated by the enzyme (via intermediate reactive oxygen species). In an attempt to localize NADH oxidase activity at the light microscope level using the cerium-diaminobenzidine (DAB)-nickel-H2O2, the cerium-DAB-cobalt-H2O2 or the cerium-alkaline lead procedures, the distribution patterns of the revealed enzyme were found to be identical to those for non-specific alkaline phosphatase and especially 5'-nucleotidase activity. With the cerium-DAB-cobalt-H2O2 visualization procedure, the distribution pattern of the final reaction product was similar to that obtained with the other two techniques but much less final reaction product was formed. Incubations for NADH oxidase activity performed in the presence of exogenous catalase or in the absence of catalase or peroxidase inhibitors did not affect the staining intensity, whereas inhibitors of 5'-nucleotidase (EDTA) and non-specific alkaline phosphatase (levamisole) always did. Therefore, phosphatases contribute to the formation of the final reaction product. Since NADH initially cannot be hydrolysed by either of these two phosphatases, then presumably nucleotide pyrophosphatase (E.C.3.6.1.9) cleaves NADH into 5'-AMP and nicotinamide mononucleotide in a first step. Both nucleotides can be hydrolysed further by the two monophosphatases. These then generate cerium phosphate which is detected by the DAB-nickel-H2O2, DAB-cobalt-H2O2 or lead visualization methods.
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PMID:Pitfalls in the light microscopical detection of NADH oxidase. 236 89

Polyclonal antibodies to native alkaline phosphatase and to native 5'-nucleotide phosphodiesterase were found to strongly cross-react with both enzymes. The antibodies also cross-react with both denatured enzymes, with glycopeptides from 5'-nucleotide phosphodiesterase, and with the oligosaccharides remaining after Pronase E digestion of the phosphodiesterase. They do not cross-react with either enzyme after their oligosaccharides have been modified or removed by periodate or trifluoromethanesulfonic acid treatment. Antibodies to denatured 5'-nucleotide phosphodiesterase do not bind to the native phosphodiesterase or alkaline phosphatase but do cross-react with denatured alkaline phosphatase even after removal or modification of the carbohydrate moieties. These results suggest that antibodies to denatured 5'-nucleotide phosphodiesterase may recognize amino acid sequence homology between alkaline phosphatase and 5'-nucleotide phosphodiesterase. However, antibodies to native enzymes apparently recognize cross-reactive determinants of the native enzymes which are carbohydrate in nature. This is the first report of antimammalian alkaline phosphatase antibodies which recognize the carbohydrate moieties of the enzyme.
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PMID:Alkaline phosphatase and 5'-nucleotide phosphodiesterase from bovine intestine are cross-reactive. 241 45

Milk samples (186) were obtained at various stages of lactation from 27 common brushtail possums (Trichosurus vulpecula). Qualitative and quantitative changes in the milk carbohydrates during early and mid-lactation were similar to those previously seen in other marsupials; the principal carbohydrate was lactose early in lactation and higher oligosaccharides in mid-lactation, and the hexose concentration reached a peak during mid-lactation. However, the late-lactation milk was unusual in that the carbohydrate was mainly lactose and its concentration remained relatively high (3.5 to 5.5%). In contrast to earlier findings on the milk of the tammar wallaby (Macropus eugenii), little or no nucleotide pyrophosphatase, beta-galactosidase and alkaline phosphatase activities were detected late in lactation.
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PMID:Changes in milk carbohydrates during lactation in the common brushtail possum, Trichosurus vulpecula (Marsupialia:Phalangeridae). 256 94

Characteristics of 5'-nucleotide phosphodiesterase (phosphodiesterase I, EC 3.1.4.1) and alkaline phosphatase (EC 3.1.3.1) activities in tumor cell lines of human and murine origin were examined. Of the 15 cell lines tested, 5'-nucleotide phosphodiesterase activity in 13 cell lines and alkaline phosphatase activity in 10 cell lines were inhibited by N-ethylmaleimide and activated by dithiothreitol (N-ethylmaleimide-sensitive), and suggested to be SH-enzymes. In contrast, the two phosphohydrolases from normal tissues were inactivated by dithiothreitol, but not by N-ethylmaleimide (dithiothreitol-sensitive). There was only one tumor cell line in which both activities were dithiothreitol-sensitive. Human hepatoma PLC/PRF/5 cells appear to possess both types of 5'-nucleotide phosphodiesterase and alkaline phosphatase, and the subcellular distribution of these enzymes in this cell line was investigated. Dithiothreitol-sensitive 5'-nucleotide phosphodiesterase and alkaline phosphatase of PLC/PRF/5 cells were localized in the plasma membrane as in normal tissues, but N-ethylmaleimide-sensitive phosphohydrolases were soluble cytosolic proteins. N-Ethylmaleimide-sensitive 5'-nucleotide phosphodiesterase and alkaline phosphatase activities from other cell lines were also recovered in the cytosol. Molecular masses of cytosolic N-ethylmaleimide-sensitive phosphohydrolases were apparently smaller than their membrane-bound dithiothreitol-sensitive counterparts, as judged from gel filtration. It was concluded that many tumor cell lines lack plasma membrane 5'-nucleotide phosphodiesterase and alkaline phosphatase, but express enzymes with similar activities in the cytosol, with properties clearly distinguishable from enzymes so far characterized.
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PMID:5'-Nucleotide phosphodiesterase and alkaline phosphatase in tumor cells: evidence for existence of novel species in the cytosol. 283 40


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