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:3.1.3.5 (5'-nucleotidase)
3,167 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mutants of Escherichia coli have been selected for the absence of 5'-nucleotidase (uridine diphosphate-sugar hydrolase) and 3'-nucleotidase (2',3'-cyclic phophodiesterase). Mutants selected for the absence of 5'-nucleotidase are of two kinds: those that lack detectable activity for the enzyme (Ush(-)), and those that possess activity when cell extracts are assayed, but not when intact cells are assayed (cryptic; Crp(-)). The latter class is probably identical to a type of mutant previously reported by Ward and Glaser. When mutants are selected for the absence of 3'-nucleotidase, Crp(-)mutants are also obtained. Thus far, however, mutants totally lacking this enzyme have not been found. The location on the genetic map of one ush mutation is at position 11 min and that of one crp mutation at approximately 67 min. In the crp mutant, 5'-nucleotidase and 3'-nucleotidase remain located in the periplasm. This mutant is also cryptic for alkaline phosphatase but not for acid hexose phosphatase. Treatment of cells with ethylenediamine-tetraacetate substantially alleviated crypticity. These data are discussed in terms of the organization of periplasmic enzymes and of the outer membrane as a permeability barrier.
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PMID:Mutants of Escherichia coli K-12 "cryptic," or deficient in 5'-nucleotidase (uridine diphosphate-sugar hydrolase) and 3'-nucleotidase (cyclic phosphodiesterase) activity. 435 92

Isopycnic equilibration and sedimentation rate studies of rat liver microsomes led previously to the assignment of microsomal constituents into group a1 (monoamine oxidase), group a2 (5'-nucleotidase, alkaline phosphodiesterase I, alkaline phosphatase and cholesterol), group a3 (galactosyltransferase), group b (NADH cytochrome c reductase, NADPH cytochrome c reductase, aminopyrine demethylase, cytochrome b(5) and P 450), and group c (glucose 6-phosphatase, esterase, nucleoside diphosphatase, beta-glucuronidase and glucuronyltransferase). Confirmation and extension of the assignment into groups has been obtained by studying the differential effect of the reagents digitonin, EDTA, and PPi. Digitonin specifically affected the equilibrium density only of the group a2 and (to a lesser extent) group a3, and not of groups b and c under conditions which preserved the structure-linked latency of nucleoside diphosphatase and galactosyltransferase. Within experimental error the rate of sedimentation of all microsomal constituents was unaffected. The morphological appearance under the electron microscope was indistinguishable from that of nondigitonin-treated microsomes, except that a few smooth membranes (< 10%) exhibited broken-looking profiles. Treatment of microsomes with EDTA or PPi detached a substantial part of RNA and released protein in excess over the amount accountable for by detachment of ribosome constituents. This detachment was confirmed by electron microscopy. EDTA and PPi decreased markedly the equilibrium density and the density dispersion of groups b and c, due mainly to the uncoating of rough elements. EDTA and PPi shifted slightly the distribution profiles of groups a towards lower densities, possibly as a result of the release of adsorbed proteins. The combination of EDTA and digitonin, used subsequently, rendered the average equilibrium density of group a2 higher than that of groups b and c. Dense subfractions were thus enriched in constituents of group a2 and showed mainly broken-looking vesicles under the electron microscope. The import of our results on the biochemical and enzymic properties of the subcellular components of the microsome fractions is discussed.
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PMID:Analytical study of microsomes and isolated subcellular membranes from rat liver. IV. Biochemical, physical, and morphological modifications of microsomal components induced by digitonin, EDTA, and pyrophosphate. 436 10

Diethylnitrosamine was injected to Sprague-Dawley rats after a partial hepatectomy, and enzyme histochemistry analysis was made after 35 weeks in the preneoplastic liver. The areas and volumes of the induced enzyme-deficient islands were calculated for glucose-6-triphosphatase, adenosine triphosphatase, and 5'-nucleotidase. The preneoplastic enzyme-deficient zones showed also an increased incorporation of tritiated thymidine.
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PMID:[Enzymatic phenotype of preneoplastic islands induced in the rat liver by diethylnitrosamine]. 610 Sep 68

A technique currently used for isolation of brush border membranes from renal and intestinal epithelium that involves vigorous tissue homogenization and sedimentation of non-luminal membranes in the presence of Mg2+ has been adapted to rat liver. Liver plasma membranes so prepared consisted almost exclusively of vesicles by electron microscopy, showed some contamination with endoplasmic reticulum and minimal contamination with mitochondria or Golgi by marker enzymes, were highly enriched in alkaline phosphatase, Mg2+-ATPase, and 5'-nucleotidase activity compared with homogenate, and showed little enrichment in (Na+, K+)-ATPase. Comparison of this enzymatic profile with cytochemical studies localizing (Na+, K+)-ATPase and alkaline phosphatase to the sinusoidal/lateral and canalicular membranes, respectively, suggested that these membranes were predominantly of canalicular origin. They had a lower (Na+ + K+)-ATPase specific activity, lower lipid content, and higher cholesterol to phospholipid molar ratio than a conventional plasma membrane preparation believed to be enriched in canaliculi. Moreover, it was possible to measure movement of D-[3H]glucose into an osmotically sensitive space bounded by these membrane vesicles.
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PMID:Isolation of a rat liver plasma membrane fraction of probable canalicular origin. Preparative technique, enzymatic profile, composition, and solute transport. 611 3

Pyrophosphate, p-nitrophenyl phosphate and a variety of pyrimidine and purine nucleotides are hydrolyzed by the solubilized membrane-bound enzymes of the brush border plasma membrane of Hymenolepis diminuta. The pH optima (or ranges) for hydrolysis of substrates are 8.0 (pyrophosphate), 8.8 (p-nitrophenyl phosphate), 8.4-8.9 (nucleoside monophosphates), and 7.1-8.1 (nucleoside triphosphates); all substrates, with the exception of nucleoside triphosphates, have a higher affinity for the solubilized enzyme at pH 7.4 than at their optimal pH for hydrolysis. ATP is degraded completely by the enzyme preparation to adenosine and inorganic phosphate, but since neither ADP nor ATP accumulate in the incubation medium it is not known whether ATP hydrolysis involves the sequential hydrolysis of terminal phosphate groups. Isoelectric focusing and various chromatographic procedures (gel permeation, ion-exchange and hydrophobic interaction chromatography) fail to separate the alkaline phosphatase, phosphodiesterase, 5'-nucleotidase, adenosine triphosphatase and ribonuclease activities associated with the solubilized membrane preparation. Additionally, inhibitor studies indicate that only a single enzyme with low substrate specificity is involved in the hydrolysis of nucleotides, p-nitrophenyl phosphate, pyrophosphate and hexose phosphate esters. Purines and pyrimidines and their nucleosides interact with the active site, and in some instances activity of the enzyme is stimulated by an unknown mechanism.
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PMID:Nucleotide hydrolysis by solubilized membrane-bound enzymes of the brush border plasma membrane of Hymenolepis diminuta. 613 88

Two different Mg2+-dependent adenosine 5'-triphosphate-hydrolyzing activities were detected in membranes of Vibrio costicola, a novel 5'-nucleotidase and an N,N'-dicyclohexylcarbodiimide-sensitive adenosine triphosphatase. The former and the latter had different requirements for Mg2+ and were selectively assayed in the membranes by using, respectively, 20 and 2 mM Mg2+. The two enzymes were extracted with a combination of Triton X-100 and octylglucoside, separated on a diethylaminoethyl cellulose column, and purified on glycerol gradients. The purified 5'-nucleotidase consisted of one major polypeptide of 70,000 daltons when analyzed on polyacrylamide gels in the presence of sodium dodecyl sulfate. The purified 5'-nucleotidase was similar in substrate specificities, divalent cation specificities, and pH profiles to the membrane-bound N,N'-dicyclohexylcarbodiimide-insensitive nucleotide-phosphohydrolyzing activity. The enzyme hydrolyzed nucleoside 5'-tri, 5'-di, and 5'-monophosphates at comparable rates. Inorganic pyrophosphate, p-nitrophenyl phosphate, glucose 6-phosphate, beta-glycerophosphate, adenosine 5'-diphosphate glucose, adenosine 3'-monophosphate, and cyclic adenosine 3',5'-monophosphate were not hydrolyzed, either im membranes or by the purified 5'-nucleotides. Actions of NaCl and KCl on the activity of the 5'-nucleotidase were studied. The enzyme was activated by both NaCl and KCl; the activation profiles however, were different for the membrane-bound and purified 5'-nucleotidase. The purified enzyme, unlike the membrane-bound enzyme, was markedly stimulated by high concentrations of NaCl (up to 3 M).
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PMID:Purification and properties of 5'-nucleotidase from the membrane of Vibrio costicola, a moderately halophilic bacterium. 616 62

The subcellular localization, kinetics of activation, and substrate specificity of the guinea pig granulocyte superoxide (O2-) generating system was investigated. Membrane-enriched particles (podosomes) were made from granulocytes by mild sonication and differential centrifugation. These podosomes are enriched threefold for known plasma membrane markers, 5'-nucleotidase, and adenylate cyclase. Podosomes made from resting granulocytes have very little NAD(P)H-dependent O2- production. Podosomes made from cells stimulated with digitonin are equally enriched for membrane markers but have a 15- to 20-fold increase in NAD(P)H-dependent O2- production. The KmAPP for NADPH is one-tenth that for NADH, but the Vmax is the same. The kinetics of digitonin-stimulated whole-cell O2- production parallel the changes in enzyme activity in these podosomes. Temperature affects both the rate and extent of activation of this enzyme. The pH optimum for the enzyme, the pH optimum for activation, and the pH optimum for whole-cell O2- production are all 7.5. Enzyme activity is increased if the cells are treated with glucose and cyanide, inhibited in cells treated with 2-deoxyglucose (2-DOG), and requires the presence of calcium for activation. These effects are similar to those found for granulocyte O2- production. Thus, the granulocyte O2- generating enzyme system is located on a fraction enriched for plasma membrane markers, and the kinetics of granulocyte production are directly related to the rate and amount of activation of this enzyme.
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PMID:Activation of the guinea pig granulocyte NAD(P)H-dependent superoxide generating enzyme: localization in a plasma membrane enriched particle and kinetics of activation. 624 12

The human promyelocytic leukemia cell line HL-60 undergoes terminal myeloid differentiation in vitro in response to a wide variety of chemicals. The tumor promoter phorbol myristate acetate induces these cells to develop macrophage-like morphology, adherence, and enzymatic characteristics. The present study confirms those observations and further documents the induction, by 16 nM phorbol myristate acetate, of 5'-nucleotidase activity, another human macrophage marker enzyme. However, more importantly, functional studies show that phorbol myristate acetate-induced HL-60 cells fail to increase above base line uninduced levels of hexose monophosphate shunt activity, superoxide generation, nitroblue tetrazolium reduction, bacterial ingestion, or complement secretion. These cells therefore possess some macrophage-like properties but do not meet several important functional criteria of macrophage identity.
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PMID:Functionally deficient differentiation of HL-60 promyelocytic leukemia cells induced by phorbol myristate acetate. 626 Mar 53

With the unique observation, using conventional cytochemistry, of acid phosphatase reaction production in the T-tubules of the posterior latissimus dorsi muscle of the chicken, the possibility of endocytosis of lysosomal enzymes by muscle cells came into question. After testing the substrate specificity of this T-tubular phosphatase, it was clear that the enzyme hydrolysed glucose 6-phosphate and beta-glycerophosphate at pH 5.0 but not cytidine-5'-monophosphate which was hydrolysed by dense bodies and autophagic vacuoles. The cytochemical evidence points to a unique phosphatase present on muscle cell membranes which apparently does not belong to the vacuolar apparatus of skeletal muscle and is not 5'-nucleotidase.
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PMID:Further studies on a unique T-tubular acid phosphatase in avian skeletal muscle. 626 12

5'-Nucleotidase, adenosine phosphorylase, adenosine deaminase and purine nucleoside phosphorylase, four enzymes involved in the utilization of exogenous compounds in Bacillus cereus, were measured in extracts of this organism grown in different conditions. It was found that adenosine deaminase is inducible by addition of adenine derivatives to the growth medium, and purine, nucleoside phosphorylase by metabolizable purine and pyrimidine ribonucleosides. Adenosine deaminase is repressed by inosine, while both enzymes are repressed by glucose. Evidence is presented that during growth of B. cereus in the presence of AMP, the concerted action of 5'-nucleotidase and adenosine phosphorylase, two constitutive enzymes, leads to formation of adenine, and thereby to induction of adenosine deaminase. The ionsine formed would then cause induction of the purine nucleoside phosphorylase and repression of the deaminase. Taken together with our previous findings showing that purine nucleoside phosphorylase of B. cereus acts as a translocase of the ribose moiety of inosine inside the cell (Mura, U., Sgarrella, F. and Ipata, P.L. (1978) J. Biol Chem. 253, 7905-7909), our results provide a clear picture of the molecular events leading to the utilization of the sugar moiety of exogenous AMP, adenosine and inosine as an energy source.
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PMID:Induction and repression of enzymes involved in exogenous purine compound utilization of Bacillus cereus. 627 19


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