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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)

Rat placental alkaline phosphatase (EC 3.1.3.1), a dimer of 135,000 daltons, is strongly activated by Mg2+. However, Zn2+ has to be present on the apoenzyme to obtain this activation. Mg2+ alone is unable to reconstitute functional active sites. Excess Zn2+ which competes for the Mg2+ site leads to a phosphatase with little catalytic activity at alkaline pH but with normal active sites at acidic pH as shown by covalent incorporation of ortho-[32P]phosphate. Two enzyme species with identical functional active sites have been reconstituted that only differ by the presence of Zn2+ or Mg2+ at the effector site. A mechanism is presented by which alkaline phosphatase activity of rat placenta would be controlled by a molecular process involving the interaction of Mg2+ and Zn2+ with the dimeric enzyme molecule.
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PMID:Mechanism of action of Mg2+ and Zn2+ on rat placental alkaline phosphatase. I. Studies on the soluble Zn2+ and Mg2+ alkaline phosphatases. 0 Nov 42

Several cell lines, originally thought to be derived from a human placenta at term but possibly HeLa-contaminated, have been studied. These cells secrete a protein indistinguishable immunochemically from the alpha subunit of chorionic gonadotropin but not the beta subunit of chorionic gonadotropin or placental lactogen. Complete chorionic gonadotropin was detected but amounted to less than 1% of the level of the alpha subunit. The cells also produce an alkaline phosphatase similar to placental alkaline phosphatase in immunochemical, gel-electrophoretic, and heat-denaturation properties. They induce tumor growth when inoculated into nude mice. These cells are aneuploid and have a model chromosome number of 66. The common HeLa karyologic markers, designated 1, 2, and 3, and A-type glucose-6-phosphate dehydrogenase are present in these cells. HeLa cells have not previously been shown to secrete the alpha subunit of hCG.
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PMID:Synthesis of alpha subunit of human chorionic gonadotrophin by presumptive HeLa cells. 1 Nov 78

Alkaline phosphatase is induced in human choriocarcinoma cells by short-chain fatty acids, especially sodium butyrate. This fatty acid increases the phosphatase activity immediately and in a nearly linear fashion. Only phosphatase with an alkaline pH optimum is induced. Both the induced alkaline phosphatase and the basal enzyme are precipitated by antiserum against term-placental alkaline phosphatase, but the choriocarcinoma phosphatase is less stable to heating than is the term-placental enzyme. The induction of alkaline phosphatase activity requires cellular synthesis of protein, RNA and DNA. The regulation of induction probably occurs at the transcriptional level.
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PMID:Regulation of the induction of alkaline phosphatase in choriocarcinoma cells by sodium butyrate. 4 10

Four different immunological methods for the determination of the placental isoenzyme of alkaline phosphatase (Regan isoenzyme) were compared in 64 normal blood donors, 23 healthy laboratory and medical staff workers and 68 pregnant women: a. Inhibition by soluble antibodies to the placental enzyme. b. Precipitation with soluble antibodies. c. Precipitation with immobilized antibodies. d. Measurement of the activity of the placental alkaline phosphatase following binding to an immunoabsorbent that has been obtained by polymerization of anti-placental-alkaline phosphatase gamma-globulin using glutaraldehyde. The immunoabsorbent method yielded the best results. The optimal conditions were evaluated for the measurement of the activity of immunoabsorbent-fixed placental (tumoral) alkaline phosphatase activity. This method was applied to 209 normal blood donors and to 239 patients with different malignant tumors: 25.5 percent of the cancer patients exhibited an elevated Regan -isoenzyme activity in the serum.
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PMID:Immunological methods for human placental alkaline phosphatase (Regan isoenzyme). 5 29

N-Butanol extracts of whole-term placenta from different individuals were prepared, and used as immunogens to raise heterologous hyperimmune sera in rabbits. Upon immunoelectrophoresis the anti-placenta antisera could recognize at least six antigenic components in the placental extract even after they had been completely absorbed with pooled male serum proteins. However, the antisera so absorbed, designated (-PMS) antisera, could still react strongly with several normal adult tissue extracts including kidney. Systematic and quantitative absorptions of the (-PMS) antisera were thus further carried out with individual butanol extracts of normal adult liver, lung, intestine, stomach, kidney, bone, pancreas, spleen, heart, cerebrum, cerebellum, breast, and packed red cells, as well as a composite extract containing equal amounts of each of the 13 adult tissue extracts. Of the six antigenic components in the placental extracts reacting with the (-PMS) antisera the only one which retained its reactivity with the antisera throughout exhaustive absorptions was associated with alkaline phosphatase activity. This immunologic and enzymologic identity was confirmed with homogeneous placental alkaline phosphatase. Extracts from each of three placentae injected into three pairs of rabbits all produced an identical antibody reaction with the unique determinant(s) of placental alkaline phosphatase. The same identity of precipitin reaction was also found with extracts of 14 other placentae against each of these antisera. It thus firmly establishes that placental alkaline phosphatase is a characteristic placenta-specific fetal protein.
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PMID:Identification of a butanol-extractable human placenta-specific antigen with alkaline phosphatase activity. 5 37

Preparations of human placental alkaline phosphatase differing in specific enzyme activities were compared by microcomplement fixation assays using monospecific antisera. While both specific enzyme activity and complement fixation units increased 15,000-fold upon purification, the ratio between these units remained constant. Separation of an alkaline phosphatase preparation into 'A' and 'B' forms by ampholine isoelectric focusing indicated that these forms also possessed the same ratio of immunoreactive enzyme protein to enzyme activity. The correspondence of complement fixation units with specific enzyme activity indicates that complement fixation with monospecific antisera can be used to analyze structural differences among alkaline phosphatase isoenzymes.
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PMID:Complement fixation for study of placental-type alkaline phosphatase. 11 92

The physiocochemical and immunological properties of alkaline phosphatase extracted from Hodgkin's nodes, non-Hodgkin's lymphoma nodes and leukemic leukocytes have been studied. The alkaline phosphatase from these three tumor types possesses the same biophysical and biochemical properties and immunological determinants as the placental alkaline phosphatase. However, it is more heat-labile than the placental isoenzyme. Immunological experiments indicate that, of these tumor types, Hodgkin's tumor contains the largest amounts of heat-labile Regan type of alkaline phosphatase.
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PMID:Occurrence of heat-labile Regan type of alkaline phosphatase in hematopoietic tumors. 11 39

Experimental evidence has been collected which signifies that autoantibody has been induced against lung heat-stable alkaline phosphatase which represented 60% of the total alkaline phosphatase of that tissue. Immunization of a male baboon with highly purified human placental alkaline phosphatase (heat-stable and cross-reactive with the baboon heat-stable enzyme) resulted in production of a precipitating factor in the immune serum which reacted with the heat-stable enzyme of both the human and baboon but not the heat-labile form of alkaline phosphatase of either species. This precipitating factor is a baboon autoantibody because 1) it had a gamma mobility on immunoelectrophoresis and retarded the electrophoretic mobility of the heat-stable enzyme from both normal and immunized baboons; 2) its titer increased as more booster injections were administered; 3) it formed a well-defined precipitin rocket with the baboon heat-stable enzyme in the Lurell's antigen-antibody crossed electrophoresis; 4) in immunodiffusion it formed a discrete precipitin line with the baboon heat-stable enzyme, which fused partially with the precipitin line of human placental alkaline phosphatase (immunogen).
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PMID:Experimentally induced autoantibody to heat-stable alkaline phosphatase in the baboon. 11 6

At least three loci determine human alkaline phosphatases [orthophosphoric-monoester phosphohydrolase (alkaline optimum), EC 3.1.3.1]: one coding for the placental form of the enzyme, at least one coding for the intestinal forms, and at least one for the liver, bone, and kidney forms. The alkaline phosphatase in cell line D98/AH-2 has been characterized by inhibition, thermostability, and electrophoretic studies. It is intestinal in type and resembles the fetal intestinal form somewhat more closely than the adult intestinal form. Intestinal alkaline phosphatase was found in the related cell lines Detroit 98, D98/S, and D98/AH-R. No placental alkaline phosphatase could be detected in any of these cell lines. This series of cell lines are believed, on the basis of earlier investigations, to be HeLa in origin but other HeLa cell lines show placental alkaline phosphatase. Loss of expression of the placental alkaline phosphatase locus probably occurred prior to the separation of Detroit-98 from the lineage leading to other HeLa cell lines and this has persisted in the Detroit-98 derivatives D98/AH-2, D98/S, and D98/AH-R. Another possibility is that placental alkaline phosphatase expression only appeared in the HeLa lineage subsequent to the separation of Detroit-98.
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PMID:Human cell lines expressing intestinal alkaline phosphatase. 29 Oct 61

Antisera against purified human placental alkaline phosphatase (PAP) and crystallized creatine kinase (CK) isoenzyme from human skeletal muscle (MM) were raised in rabbits. The PAP antiserum was shown by radial immunodiffusion not to react with purified alkaline phosphatases from human liver and intestine, nor with the alkaline phosphatase in sera from patients with osteoblastic bone disease. CK antiserum also demonstrated no cross-reaction and was precipitated quantitatively by its homologous antisera. A "rocket" electroimmunoassay for PAP and CK is described. The method is simple, reproducible and uses small volumes of antiserum. The isoenzyme patterns were compared with those developed by several electrophoretic methods. These techniques share with other immunoassay the advantages of specificity for the antigen and enhance the quantitation of isoenzyme assays.
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PMID:Immunoassay of enzymes. 40 31


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