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 effect of phenylglyoxylation on brush-border-membrane functions was studied with membrane vesicles from rat kidney cortex. Na+-gradient-dependent uptake of phosphate, glucose and alanine was inhibited by 65, 88 and 70% by pre-incubation of vesicles with 50 mM-phenylglyoxal for 2 min. The inhibition showed a dependency for alkaline pH. Borate co-operativity in butanedione inactivation was used to prove that inhibition was caused by arginine modification. Intravesicular volumes, alkaline phosphatase, aminopeptidase M and Na+-H+ exchange were not affected by phenylglyoxal treatment. Inhibition of phosphate uptake was studied in more detail and showed that the chemical modification introduced by phenylglyoxal inhibited the overshoot of phosphate uptake caused by the Na+ gradient, and decreased the apparent maximal velocity of the phosphate-transport system in its interaction with Na+. Phosphate uptake measured in the absence of Na+ was not affected by phenylglyoxal. Shunting of the transmembrane electrical potential with K+ and valinomycin had no effect on phenylglyoxal inhibition, proving that the alteration of transmembrane electrical potential could not be responsible for this effect. Phenylglyoxal had no ionophoric effect on the Na+ gradients studied (1-100 mM). Na+ efflux was also unaffected by phenylglyoxal treatment. Na+, harmaline and amiloride were ineffective in protecting against phenylglyoxal inhibition, suggesting that the site modified was not an Na+-binding site. These results indicate the involvement of highly reactive arginine residues in phosphate, glucose and alanine uptake.
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PMID:Effect of arginine modification on kidney brush-border-membrane transport activity. 650 41

Chromatofocussing was used for the separation of brush-border membrane proteins from calf kidney into 4 or 5 fractions over the pH range 4.0 to 7.4. These fractions were reconstituted into proteoliposomes by gradient centrifugation. Determination of the sodium-dependent solute uptake by proteoliposomes reconstituted from different chromatofocussed fractions showed that the sodium-D-glucose cotransport system was present in the fraction eluted between pH 5.3 and 5.8, and that the sodium-phosphate cotransport was present in fractions eluted between pH 4.6 and 5.3 and between pH 5.8 and 6.6, sodium-alanine cotransport could be detected in almost all fractions. Marker enzymes of the brush-border membrane, such as alkaline phosphatase, gamma-glutamyltransferase and aminopeptidase M etc. were also found to be eluted at pH 7.0-7.4, 4.0-4.1 and 5.6-5.8, respectively. These results suggest that chromatofocussing is a promising tool for the separation of membrane proteins and for pre-purification of the sodium-D-glucose cotransport system. It can be further concluded that the sodium-dependent phosphate transport across the brush-border membrane is not dependent upon alkaline phosphatase activity.
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PMID:Chromatofocussing and centrifugal reconstitution as tools for the separation and characterization of the Na+-cotransport systems of the brush-border membrane. 654 Jan 19

Canalicular plasma membranes were isolated from rat liver homogenates using nitrogen cavitation and calcium precipitation methods. Compared with homogenates, the membranes were enriched 55- to 56-fold in gamma-glutamyltransferase, aminopeptidase M, and alkaline phosphatase activities and showed very low enrichment in markers of other membranes. By electron microscopy, the membrane preparation contained neither junctional complexes nor contaminating organelles and consisted exclusively of vesicles. The presence of vesicles was also evident from the osmotic sensitivity of D-[6-3H]glucose uptake into the membrane preparation. Antisera obtained from rabbits immunized with highly purified rat kidney gamma-glutamyltransferase inhibited the transferase activity of intact or Triton X-100-solubilized membranes by 45-55%. Treatment of vesicles with anti-gamma-glutamyltransferase antisera and anti-rabbit IgG antisera increased the apparent density of the membranes during sucrose density gradient centrifugation. gamma-Glutamyltransferase and aminopeptidase M activities were selectively removed from the vesicles by limited proteolysis with papain without changing the intravesicular space or alkaline phosphatase activity of the membranes. Specific binding of anti-gamma-glutamyltransferase antibody to the outer surface of isolated hepatocytes was observed as measured by the antisera and 125I-labeled protein A; binding followed saturation kinetics with respect to antibody concentration. These data indicate that the isolated canalicular membrane vesicles are exclusively oriented right-side-out and that gamma-glutamyltransferase and aminopeptidase M are located on the luminal side of rat liver canalicular plasma membranes.
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PMID:Rat liver canalicular membrane vesicles. Isolation and topological characterization. 683 95

A brush border membrane fraction isolated from hog kidney cortex was solubilized with 0.5% Triton X-100 and subjected to affinity chromatography on a phlorizin polymer. As demonstrated by transport studies with reconstituted proteoliposomes, the polymer adsorbs the sodium-dependent D-glucose transport system. The latter can be eluted from the polymer by 0.5 M D-glucose. The purified fraction contains 0.4% of the membrane protein extract and exhibits a 20--30-fold higher transport activity than the crude membrane extract. Other brush border membrane proteins such as alkaline phosphatase and aminopeptidase M are markedly reduced in the purified fraction. Thus, affinity chromatography on a phlorizin polymer is a suitable tool for the isolation of the sodium-glucose transport system present in brush border membranes.
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PMID:Partial purification of hog kidney sodium-D-glucose cotransport system by affinity chromatography on a phlorizin polymer. 719 13

A 34-year-old man was admitted with lumbago and anemia in November 1992. Hematological examination revealed an Hb 9.2g/dl, WBC count 13,500 microliters (33% blasts), and monocyte count 3,400/microliters. Bone marrow examination showed hyperplasia with dysplasia in trilineage blood cells and increased blasts (21.8%). A diagnosis of refractory anemia with excess of blasts in transformation (RAEB in T) was made. Cytochemical examination revealed the neutrophils in the peripheral blood were 66.5% positive for alpha-naphthyl butyrate esterase inhibited by sodium fluoride, 4.0% positive for peroxidase and 75% positive for alkaline phosphatase. The results of immuno-alkaline phosphatase stainings (avidin biotin alkaline phosphatase complex method) of neutrophils were as follows; CD16 (94.5%), CD24 (91.0%), CD13 (93.0%), CD14 (52.5%), CD33 (39.0%), CD36 (16.5%), HLA-DR (17.0%). These neutrophils exhibited monocyte-specific features and failed to show characteristics of neutrophils.
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PMID:[CD14-positive and nonspecific esterase-positive neutrophils in a patient with refractory anemia with excess of blasts in transformation]. 750 51

Two anti-nerve growth factor receptor (LNGFR or p75NGFR) antibodies, Me20.4 and Me8211, label stromal cells with dendritic features in fresh smears and in formalin-fixed, paraffin-embedded human bone marrow (BM). The LNGFR+ cells have an oval nucleus, a scanty cytoplasm with long dendrites that intermingle with the hematopoietic cells, line the abluminal side of sinus endothelial cells, and provide the scaffold for the hematopoietic marrow. At the electron microscopy level, the immunogold tag labels the body and the long branching dendrites of fibroblast-like cells with scanty cytoplasm containing mitochondria, endoplasmic reticulum, and dense bodies. The LNGFR+ cells are positive for alkaline phosphatase, reticulin, collagen III, vimentin, TE-7, and CD13 but negative for endothelial (vWF, CD34, Pal-E), neural (CD56, neurofilament) and leukocyte markers (CD45, CD68). The LNGFR+ stromal cells appear in the fetal BM before the hematopoietic activity begins, originate from the vessel adventitia, and radiate in the Bm cavity. Long-term BM culture (LTBMC) in vitro contain LNGFR+ stromal cells. We document the presence of RNA message for the low- (LNGFR) and the high-affinity NGF receptor (NTRK1) by using RT-PCR on fresh BM aspirate and on LTBMC. BM biopsies from patients with hematologic fibrogenic diseases and in cytokine-treated cancer patients are evaluated for LNGFR+ cells: the amount of stained cells is correlated with the traditional reticulin stain in cases of myelofibrosis, therapy-related myelodysplasia, leukemia, and detected an increase of stromal cells in cytokine-treated patients. The anti-LNGFR antibodies represent a specific membrane marker for the adventitial reticular cells (ARC) of the human marrow and allow precise evaluation and quantitation of this important BM microenvironment component in vivo and in vitro.
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PMID:Bone marrow stroma in humans: anti-nerve growth factor receptor antibodies selectively stain reticular cells in vivo and in vitro. 768 1

We investigated the phenotypes of blast cells of 53 patients with acute leukemia by a modified streptavidin-biotin alkaline phosphatase (SAB-AP) labeling technique, using a panel of monoclonal antibodies [MoAb; anti-CD11b, CD13, CD14, CD33, CD34, CD41, CD3, CD7, CD10, CD19, anti-HLA-DR, and anti-myeloperoxidase (MPO)]. The selection of an optimal fixative solution for each antigen from five options of various combinations of formalin, acetone, methanol, and/or ethanol, successfully conserved cell morphology and improved specific reaction compared with the conventional methods which used a single fixative for multiple antigens. We compared the SAB-AP results with those obtained by flow cytometry (FCM) for surface markers in each case. High concordance rates for both positive and negative results were observed for each marker. However, positive reaction for some markers (anti-CD13, CD14, CD33, and CD34) were often noted only in the cytoplasm by the SAB-AP method, indicating that combination of these two methods is essential for the precise immunophenotyping of poorly differentiated leukemia cells.
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PMID:Usefulness of immunocytochemistry for phenotypical analysis of acute leukemia; improved fixation procedure and comparative study with flow cytometry. 771 39

The specific activities of aminopeptidase A (APA), aminopeptidase M (APM), and dipeptidyl-aminopeptidase IV (DP IV) were determined in isolated brain microvessels and in brain homogenate of rats with different ages (between 1 and 8 weeks old). In addition, the blood-brain barrier (BBB)-specific enzymes gamma-glutamyltranspeptidase (gamma-GT) and alkaline phosphatase (ALP) were measured. As similarly described by others, gamma-GT activity increased during this time period by fourfold, whereas ALP increased between weeks 1 and 2 and declined thereafter. DP IV activity increased fivefold during the first 8 weeks after birth and APM activity increased by twofold. A decrease of APA activity was found between weeks 1 and 2 after birth followed by an increase thereafter. The development of aminopeptidase activities responsible for the processing of specific neuropeptides acting on brain microvessels may be important in the development of regulation processes for cerebral blood flow and BBB permeability in the maturing animal.
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PMID:Developmental changes of enzymes involved in peptide degradation in isolated rat brain microvessels. 799 52

Glycosyl-phosphatidylinositol-anchored membrane proteins (GPI-proteins) are normally identified either by cleavage of the lipid anchor using (glycosyl)phosphatidylinositol-specific phospholipases C or D (GPI-PLs) or by metabolic labeling of the lipid moiety with specific building blocks. Therefore, methods for discrimination between transmembrane proteins and GPI-proteins on the basis of their physicochemical properties are desirable. Here we are presenting a selective extraction method for typical well-characterized mammalian GPI-proteins, e.g., acetylcholine esterase, alkaline phosphatase, 5'-nucleotidase, and lipoprotein lipase, using a derivative of taurocholate. The results were compared to those obtained with well-characterized transmembrane proteins, e.g., insulin receptor and hydroxymethyl glutaryl coenzyme A-reductase, glucose transporters, or aminopeptidase M and several commercially available detergents. With regard to total membrane proteins, it was possible to selectively enrich GPI-proteins up to 8- to 14-fold by using concentrations between 0.1 and 0.3% of 4'-NH2-amino-7 beta-benzamido-taurocholic acid (BATC). In addition, the cleavage specificity and efficiency of (G)PI-PLs were increased in the presence of identical concentrations of BATC compared to commonly used detergents, e.g., Nonidet P-40. Therefore, the present study shows that the use of BATC facilitates the identification of glycosyl-phosphatidylinositol-anchored membrane proteins.
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PMID:4'-Amino-benzamido-taurocholic acid selectively solubilizes glycosyl-phosphatidylinositol-anchored membrane proteins and improves lipolytic cleavage of their membrane anchors by specific phospholipases. 813 45

Leukemic transformation in essential thrombocythemia (ET) is rare. We describe a patient with ET which transformed to megakaryoblastic leukemia with myelofibrosis after treatment with melphalan for 8 years. His course after transformation smouldered for 20 months without antileukemic chemotherapy. A 61-year-old man was referred by a local doctor to Niigata University Hospital due to nasal bleeding in June 1984. Complete blood count (CBC) was as follows; hemoglobin 12.4 g/dl, platelets 268.8 x 10(4)/microliters, and white blood cells 11,900/microliters, with differentials of 39% PMN, 1% basophils, 2% eosinophils, 4% monocytes, and 13% lymphocytes. Bone marrow examination revealed hyperplasia of megakaryocytes without increase of reticulin fibers. Neutrophil alkaline phosphatase activity and karyotype of marrow cells were normal. ET was diagnosed. He was followed up by local doctor. The platelet count was controlled at a level of approximately 40 x 10(4)/microliters with melphalan for eight years. In January 1992 he developed pain in his lower extremities. He was admitted to our hospital on May 29, 1992. CBC was as follows; hemoglobin 8.9 g/dl, platelets 14.3 x 10(4)/microliters, and white blood cells 3,500/microliters, with differentials of 25% PMN, 5% monocytes, 28% lymphocytes, and 24% blasts. Bone marrow aspiration was unsuccessful and bone marrow biopsy revealed increases in fibroblasts and collagen fibers. Circulating blasts were positive for CD4, CD7, CD25, CD13, CD33, CD34, and HLA-DR and partly positive for CD41 and CD36. In ultrastructural cytochemistry blasts were positive for platelet peroxidase but negative for myeloperoxidase. Cytogenetic study revealed 46, XY, +der (1) t(1:7) (p11;q11) in all of five metaphases. He was diagnosed with megakaryoblastic leukemia accompanied by myelofibrosis.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Essential thrombocythemia in transformation to smouldering megakaryoblastic leukemia with myelofibrosis]. 853 33


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