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)

Human placental microsomal 5'-nucleotidase (EC 3.1.3.5) was prepared free of alkaline phosphatase by isoelectric focusing. A total of seven electrophoretic variants were isolated during the preparation of six placentas. Only three to six variants were found in a single placenta. The isoelectric pH's were 6.70, 6.44, 6.23, 6.02, 5.76, 5.63 and 5.44. These were found to be composed of variable quantities of a large, medium and low molecular weight form. The apparent molecular weights of the medium and light form of the enzyme were 86 500 and 43 500, respectively, as estimated from Stokes radius and sedimentation velocity determinations. The electrophoretic variants were not distinguishable with respect to specific activity and Michaelis constants for AMP, GMP or CMP or inhibition by ATP, CTP or adenosine. These electrophoretic variants appeared to be pseudoisozymes based upon different states of aggregation of a common primary sequence. There was a wide range of substrate specificity among nucleoside 5'-monophosphates which included 2-deoxyribose compounds. With AMP as 100, substrate activity was: CMP, 122; NMN, 74; GMP, 68: IMP, 63; XMP, 28 and UDP-glucose, 68. The Michaelis constants for AMP, GMP and CMP ranged from 12-18 muM, from 33-67 muM and from 170-250 muM, respectively. Although 5'-nucleotidase was active in the absence of divalent cation, 5 mM MgCl2 stimulated the enzyme activity to 234% of control and shifted the pH optimum of 9.8 to a plateau from pH 7.4-9.8.
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PMID:Purine catabolism in man: characterization of placental microsomal 5'-nucleotidase. 0 35

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

1. Highly sensitive technique are described for the assay of plasma membrane (5'-nucleotidase, alkaline phosphatase), microsomal (neutral alpha-glucosidase, leucyl-2-naphthylamidase) and biliary canalicular (gamma-glutamyltransferase) enzymes and for nine acid hydrolases (acid phosphatase, phosphodiesterase, beta-glucosidase, alpha-glucosidase, alpha-galactosidase, beta-galactosidase, alpha-mannosidase, N-acetyl-beta-glucosaminidase, beta-glucuronidase) in human liver. 2. Optimum and specific assay systems have been developed which give linear kinetics for all enzymes. 3. The range of enzyme activities in samples of human liver, obtained by closed needle biopsy, and sera have been determined.
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PMID:Enzyme activities in human liver biopsies: assay methods and activities of some lysosomal and membrane-bound enzymes in control tissue and serum. 1 4

gamma-Glutamyl transpeptidase (GGTP) is a sensitive but nonspecific index hepatobiliary disease. In infectious mononucleosis (IM) or the mononucleosis-like disease attributable to cytomegalovirus (cytomegalovirus-induced IM), GGTP reverted to normal later than aspartate aminotransferase and alkaline phosphatase. In three cases elevated serum GGTP activity persisted for up to 24 months -- raising the question of persistent 'post-IM' hepatitis. Such prolonged GGTP activity was unusual in other late IM specimens. Possible, but unlikely, causes for such persistent GGTP activity are an unusual degree of hepatic damage during acute IM, excessive induction of microsomal enzyme system activity by drugs, or unusual Epstein-Barr virus carrier state activation that might contribute to ongoing hepatic structural damage. Other markers of chronic hepatocellular disease including aspartate aminotrasferase, alkaline phosphatase, and bilirubin were normal in late specimens from these 3 patients. The cause of their persistent elevated GGTP activities remains unknown.
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PMID:Late persistence of serum gamma-glutamyl transpeptidase activity after mononucleosis. Report of 3 cases. 1 21

Plasma membranes were isolated from the livers of control and Streptococcus pneumoniae-infected rats. This work, therefore, represents the first isolation of plasma membranes from infected actron microscopy and by the use of enzyme markers for microsomes (glucose-6-phosphatase), mitochondria (glutamate and malate dehydrogenases), and lysosomes (acid phosphatase). Plasma membranes from infected cells banded at the same sucrose density as plasma membranes from uninfected cells. Moreover, equivalent amounts of plasma membranes could be isolated from control and infected rat livers. There were, however, significant alterations in the enzyme complement of the plasma membrane after infection. 5'-Nucleotidase activity was significantly decreased, whereas alkaline phosphatase activity was significantly increased. Kinetic analysis demonstrated that only the Vmax and not the Km of these two enzymes was changed, suggesting that the altered affinity of the enzymes for substrate was not the mechanism responsible for the observed alterations. No change in the mitochondrial enzyme markers was observed after infection, but the specific activity of microsomal glucose-6-phosphatase decreased significantly. Possible explanations for the observed alterations are discussed.
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PMID:Isolation and partial characterization of plasma membranes from the livers of control and Streptococcus pneumoniae-infected rats. 1 27

The levels of serum gamma-glutamyl transpeptidase (GGT) and, when appropriate, alkaline phosphatase (AP) and 5'-nucleotidase (NTD) have been measured as a routine in 276 patients with malignant haematological diseases during a 26-month trial period. GGT levels add no prognostic information to the routine haematological surveillance of leukaemia. Polychemotherapy does not appear to be an inducer of liver drug-metabolising microsomal enzymes. Polycythaemia rubra vera, myelofibrosis and chronic lymphocytic leukaemia may cause little change in GGT, AP and NTD levels despite marked hepatomegaly. A raised GGT in Hodgkin's disease and non-Hodgkin lymphoma is generally associated with active and widespread disease, but not necessarily a sign of malignant tissue in the liver. The elevations of GGT in myeloma may be secondary to liver infiltration though this group merits further detailed study.
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PMID:Evaluation of the usefulness of serum gamma-glutamyl transpeptidase levels in the management of haematological neoplasia. 2 19

A purine nucleoside triphosphate phosphohydrolase (unspecified diphosphate phosphohydrolase, EC 3.6.1.15) was chromatographically separated from the bulk of alkaline phosphatase activity by gel filtration chromatography of butanol and EDTA extracts of fracture callus and bovine epiphyseal cartilage. The callus enzyme differed from alkaline phosphatase in a variety of characteristics. The purine nucleoside triphosphate phosphatase hydrolyzed a more specific group of substrates, required Ca2+ and Mg2+ for optimal activity, remained unaffected by a potent alkaline phosphatase inhibitor, and demonstrated a narrower range of optimal pH for catalytic activity. The enzyme was localized in the microsomal pellet following subcellular fractionation of callus chondrocytes. These characteristics indicate a role for the enzyme in Ca2+ transport.
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PMID:Identification, characterization and localization of a (Ca2+ + Mg2+)-activated purine nucleoside triphosphate phosphohydrolase from calcifying cartilage. 3 14

The localization of alkaline phosphatase in HeLa cells was examined by electron microscopic histochemistry and subcellular fractionation techniques. Two monophenotypic sublines of HeLa cells which respectively produced Regan and non-Regan isoenzymes of alkaline phosphatase were used for this study. The electron microscopic histochemical results showed that in both sublines the major location of alkaline phosphatase is in the plasma membrane. The enzyme reaction was occasionally observed in some of the dense body lysosomes. This result was supported by data obtained from a subcellular fractionation study which showed that the microsomal fraction rich in plasma membrane fragments had the highest activity of alkaline phosphatase. The distribution of this enzyme among the subcellular fractions closely paralleled that of the 5'-nucleotidase, a plasma membrane marker enzyme. Characterization of the alkaline phosphatase present in each subcellular fraction showed identical enzyme properties, which suggests that a single isoenzyme exists among fractions obtained from each cell line. The results, therefore, confirm the reports suggesting that plasma membrane is the major site of alkaline phosphatase localization in HeLa cells. The absence of any enzyme reaction in the perimitochondrial space in these cultured tumor cells also indicates that the mitochondrial localization of the Regan isoenzyme reported in ovarian cancer may not be a common phenomenon in Regan-producing cancer cells.
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PMID:Plasma membrane localization of alkaline phosphatase in HeLa cells. 5 27

Different acute doses of chlordane enhance the serum alkaline phosphatase activity in Indian desert gerbils. The damage to parenchymal cells of liver, and hepatic microsomal enzyme induction as a result of chlordane treatment are discussed as the possible reasons for the increase in serum alkaline phosphatase activity.
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PMID:Acute chlordane toxicity on the serum alkaline phosphatase activity of Meriones hurrianae Jerdon. 6 Sep 75

The effects of salts and non-ionic detergents on renal brush borders have been studied. 2 M sodium chloride, iodide or thiocyanate dissociated up to 40% of the protein from the brush borders, destroying the core filaments and resulting in the formation of membrane vesicles; EDTA had a similar effect on structure but released little protein. Triton X-100 and Nonidet P-40 extracted up to 60% of the protein including the major membrane glycoproteins and the enzymes trehalase, maltase and aminopeptidase (microsomal). Triton exhibited a selective effect on lipids removing phosphatidylserine, phosphatidylethanolamine and sphingomyelin but not the bulk of the phosphatidylcholine or cholesterol. The residual structures after Triton extraction comprised the core filaments associated with vesicles of lipid containing alkaline phosphatase and several other proteins. Treatment of these core-vesicle complexes with 2 M sodium chloride dissociated the filaments, releasing the vesicles which could be recovered as a pellicle on centrifugation. It is suggested that the proteins found in the vesicles might serve to interconnect the core filaments with the lipid bilayer.
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PMID:Studies on the structure of the rabbit kidney brush border. 11 89


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