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)

5'-Nucleotidase, assayed as 5'-AMPase, has been extensively characterized and established as a stable, quantitative plasma membrane marker in HeLa S3 cells. The membrane 5'-AMPase has a Km of 7.0 microM. Relative affinities of the other 5'-mononucleotides for the enzyme are 5'-GMP > 5'-TMP > 5'-UMP > 5'-CMP. There are activity optima at pH7 and 10; the latter is Mg(2+)-dependent. The membrane preparations have a small amount of acid phosphatase activity that is distinct from 5'-AMPase activity but no alkaline phosphatase. AOPCP, ADP, and ATP are strongly inhibitory. Mg2+, Ca2+, or Co2+ additions do not affect the pH 7.0 activity; Mn2+ activates slightly, whereas Zn2+, Cu2+, and Ni2+ are inhibitory. EDTA slowly inactivates, but removal of the EDTA without the addition of divalent cations restores activity. The inactivation is also substantially reversed by Co2+ or Mn2+, but reactivability by divalent cations decreases with time in EDTA. ConA strongly inhibits, and alpha-methyl-D-mannoside or glucose (the latter much less efficiently) relieves the inhibition, indicating that the 5'-AMPase is a glycoprotein. Histidine is also inhibitory. Ouabain, phloretin, cytochalasin B, cysteine, phenyl-alanine, MalNEt, and IAA are without effect. 5'-AMPase activity codistributes with pulse-bound [3H]ouabain when either of two cell fractionation procedures are used. The 5'-AMPase activity per cell is constant at different cell densities in exponentially growing cells, and activity per unit cell volume remains constant throughout the cell cycle. These properties, together with its absence in other organelles, its stability to storage, its insensitivity to certain experimental manipulations, and its general insensitivity to inhibitors of specific transport systems, make 5'-AMPase a useful quantitative marker in studies on the regulation of HeLa membrane transport systems. Key Words: HeLa, 5'-nucleotidase, plasma membrane marker, non-specific phosphatases, divalent ions, ConA, AOPCP, cell cycle, mitochondria, transport inhibitors.
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PMID:Characterization of HeLa 5'-nucleotidase: a stable plasma membrane marker. 4 80

1. The distributions of several enzymes and other marker components were examined after zonal centrifugations of whole homogenates from glucose-repressed Saccharomyces cerevisiae on sucrose and iso-osmotic Ficoll, and the composition and morphology of the fractions were investigated. 2. After high-speed zonal centrifugation most of the protein, acid and alkaline phosphatases, alkaline pyrophosphatase, adenosine monophosphatase, beta-fructofuranosidase, alpha-mannosidase, NADPH-cytochrome c oxidoreductase and an appreciable amount of phospholipid and sterol were non-sedimentable, i.e. were at densities below 1.09 (g/cm3). Most of the RNA was at p=1.06-1.08 in Ficoll and at p=1.09-1.11 in sucrose. 3. The bulk of the Mg2+-dependent adenosine triphosphatase (Mg-ATPase) was coincident with the main peak of phospholipid and sterol, at median density 1.10, which was also rich in smooth-membrane vesicles. In Ficoll, a minor peak of phospholipid and sterol at p-1.12-1.15 contained a smaller part of the oligomycin-insensitive Mg-ATPase and heavy membrane fragments. In sucrose, several minor peaks of Mg-ATPase were in the mitochondrial density range, and a peak of oligomycin-insensitive Mg-ATPase coincident with a minor peak of phospholipid and sterol at around p-1.25 contained heavy membrane fragments of high carbohydrate content, especially mannose. 4. Further purification of the oligomycin-insensitive Mg-ATPase containing membrane preparations was performed on Urografin gradients. 5. It is argued that the oligomycin-insensitive Mg-ATPase containing membranes are fragments of the plasma membrane, but have different densities because they contain different amounts of glycoprotein particles.
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PMID:Distribution of membranes, especially of plasma-membrane fragments, during zonal centrifugations of homogenates from glucose-repressed Saccharomyces Cerevisiae. 13 74

A survey of Salmonella typhimurium enzymes possessing phosphatase or phosphodiesterase activity was made using several different growth conditions. These studies revealed the presence of three major enzymes, all of which were subsequently purified: a cyclic 2' ,3'-nucleotide phosphodiesterase (EC 3.1.4.d), an acid hexose phosphatase (EC 3.1.3.2), and a nonspecific acid phosphatase (EC 3.1.3.2). A fourth enzyme hydrolyzed bis-(p-nitrophenyl)phosphate but none of the other substrates tested. No evidence was found for the existence of an alkaline phosphatase (EC 3.1.3.1) or a specific 5'-nucleotidase (EC 3.1.3.5) in S. typhimurium LT2. All three phosphatases could be measured efficiently in intact cells, which suggested a periplasmic location; however, they were not readily released by osmotic shock procedures. The nonspecific acid phosphatase, which was purified to apparent homogeneity, yielded a single polypeptide band on both sodium dodecyl sulfate and acidic urea gel electrophoretic systems.
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PMID:Resolution and purification of three periplasmic phosphatases of Salmonella typhimurium. 19 12

1. The subcellular distribution and maturation of Ruthenium Red-insensitive Ca(2+) transport activity were determined in livers of rats ranging in age from 3 days pre-term to 10 weeks of adult life and compared with those of glucose 6-phosphatase, 5'-nucleotidase and Ruthenium Red-sensitive Ca(2+) transport. Initial rates of Ruthenium Red-insensitive Ca(2+) transport were highest in those fractions enriched in glucose 6-phosphatase, i.e. the microsomal fraction; this fraction was devoid of Ruthenium Red-sensitive Ca(2+) transport activity. Although the heaviest fraction (nuclear) contained significant amounts of 5'-nucleotidase activity it was devoid of Ruthenium Red-insensitive Ca(2+) transport activity. 2. Foetal rat liver contain minimal amounts of Ruthenium Red-insensitive Ca(2+) transport activity, glucose 6-phosphatase and 5'-nucleotidase activities. These begin to be expressed concomitantly soon after birth; Ruthenium Red-insensitive Ca(2+) transport is maximal by 3 to 4 days and remains so for up to at least 10 weeks of adult life. Glucose 6-phosphatase also reaches a peak at 3-4 days, but then rapidly decreases to approach adult values. Maximal activity of 5'-nucleotidase in the microsomal and nuclear fractions is seen about 4-6 days after birth; this enzyme activity remains increased for up to about 10 days and then falls, but not as rapidly as glucose 6-phosphatase. It is tentatively suggested that the bulk of the Ruthenium Red-insensitive Ca(2+) transport is attributable to the system derived from the endoplasmic reticulum. 3. Administration of glucagon to adult rats enhances by 2-3-fold the initial rate of Ruthenium Red-insensitive Ca(2+) transport in the intermediate but not the microsomal fraction. The hormone-induced effect is fully suppressed by co-administration of puromycin, is dose-dependent with half-maximal response at approx. 1mug of glucagon/100g body wt. and time-dependent exhibiting a half-maximal response about 1h after administration of the hormone. 4. Ruthenium Red-insensitive Ca(2+) transport in the post-mitochondrial fraction of foetal liver also responds to the administration in situ of glucagon. The response, which also is prevented by co-administration of puromycin, is maximal in those foetuses nearing term. The suggestion is made that these effects of the hormone on Ruthenium Red-insensitive Ca(2+) transport are an integral part of the physiological network in the liver cell.
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PMID:The subcellular location, maturation and response to increased plasma glucagon of ruthenium red-insensitive calcium-ion transport in rat liver. 21 18

Following rapid isolation, it has been found that Golgi apparatus from ethanol-intoxicated animals contain high levels of galactosyltransferase but also detectable glucose-6-phosphatase and microsomal esterase, as well as 5'-nucleotidase activity. In experiments carried out in parallel on littermate animals but without intoxication, similar recoveries and specific activities of the four enzymes were observed. Morphologic analysis of Golgi fractions isolated from control animals demonstrated no striking morphologic difference to those from the ethanol-intoxicated animals. Indeed, using galloyl glucose-lead staining techniques to mark the lipoprotein particles in situ, it was found that all Golgi apparatus of hepatocytes from control animals were marked by very low density lipoprotein particles. It is therefore concluded that within the limits of the present analyses, Golgi fractions isolated from control animals are as valid as those isolated from ethanol-intoxicated rats.
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PMID:Golgi fractions from livers of control and ethanol-intoxicated rats. Enzymic and morphologic properties following rapid isolation. 22 39

Resident mouse peritoneal macrophages were incubated in Sephadex G-100 fractions of supernates from concanavalin A-stimulated lymphocytes. A significant effect of the lymphocyte supernatant fractions containing mediators on macrophage 5'-nucleotidase, glucose-1 14C oxidation, cell maintenance, and migration is reported. The 5'-nucleotidase was depressed to an extent similar to that seen in activated macrophages obtained from Listeria-infected mice. On the other hand, glucose-1-14C oxidation was enhanced, but not to the same degree as seen in the counterparts in vivo. Whereas migration inhibitory factor (MIF) and cell adherence-augmenting activity were found in a number of adjacent fractions, the metabolic effects were found predominantly in a single fraction. Resident peritoneal macrophages or those elicited by the injection of a lymphocyte-derived chemotactic factor were more responsive with respect to the biochemical changes than caseinate-elicited macrophages. On the other hand, caseinate-elicited macrophages appeared to be more sensitive with respect to the effects of mediator(s) on cell retention. A possible dissociation between MIF and cell-adherence augmenting activity, on the one hand, and the entities that stimulate glucose-1-14C oxidation is reported, based on fractionation studies, and loss of the latter activity upon storage of lymphocyte supernates.
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PMID:Alteration of some functional and metabolic characteristics of resident mouse peritoneal macrophages by lymphocyte mediators. 35 48

Adenine nucleotide breakdown to nucleosides and purine bases was measured in cultures of human lymphoblastoid cells following: 1) the inhibition of oxidative phosphorylation in the absence of glucose or 2) the addition of 2-deoxyglucose. A mutant cell line, deficient in adenosine kinase, in the presence of an adenosine deaminase inhibitor was used to measure utilization of the two pathways of AMP catabolism involving initial action of either purine 5'-nucleotidase or AMP deaminase. In such a system the appearance of adenosine induced by the oxidative phosphorylation inhibitor, rotenone, implies that approximately 70% of AMP breakdown occurs via dephosphorylation. By the same method, deamination accounts for 82% of AMP breakdown when 2-deoxyglucose is added. The occurrence of AMP dephosphorylation is not correlated with elevated concentrations of substrate or with decreased concentrations of the inhibitors of 5'-nucleotidase, ATP and ADP. Dephosphorylation occurs if, and only if, the adenylate energy charge decreases to about 0.6 in these experiments. In cultures deprived of glucose and oxygen, adenine nucleotide degradation via dephosphorylation results in recovery of normal energy charge values.
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PMID:Adenine nucleotide degradation during energy depletion in human lymphoblasts. Adenosine accumulation and adenylate energy charge correlation. 47 72

Whole sheets of plasma membrane, each with their attached flagellum, were purified from Trypanosoma brucei. The method devised for their isolation included a new technique of cell breakage that used a combination of osmotic stress followed by mechanical sheer and avoided the problem of extreme vesiculation as well as the trapping of organelles in cell 'ghosts'. The purified membranes all contained the pellicular microtubular array. The antigenic surface coat was completely released from the plasma membrane during the isolation procedure. The membranes had a very high cholesterol/phospholipid ratio (1.54). A large proportion (42%) of the cellular DNA was recovered in the plasma-membrane fraction unless a step involving deoxyribonuclease treatment, which decreased the DNA content to less than 13%, was included before secrose-density gradient centrifugation. This step also aided the separation of plasma membranes from other cellular components. The ouabain-sensitive Na+ + K+-stimulated adenosine triphosphatase and adenylate cyclase co-purified with the plasma membranes. Although 5'-nucleotidase was thought to be a plasma-membrane component, it was easily detached from the membrane. The purified membranes were essentially free of L-alanine-alpha-oxoglutarate aminotransferase, L-asparte-alpha-oxoglutarate aminotransferase, malate dehydrogenase, oligomycin-sensitive adenosine triphosphatase, glucose 6-phosphatase, Mg2+-stimulated p-nitrophenyl phosphatase and catalase.
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PMID:The isolation and partial characterization of the plasma membrane from Trypanosoma brucei. 48 94

The kinetic model of carbohydrate metabolism has been expanded to include: (a) the accumulation of alpha and beta-cellulose, insoluble cell-wall glycogen and mucopolysaccharide; (b) the role of RNA turnover as a source of carbon for end-product synthesis and as a buffer regulating the level of uridine nucleotides in this metabolic network; and (c) the role of purine-nucleoside phosphorylase, 5'-AMP nucleotidase, nucleosidediphosphate kinase and polynucleotide phosphorylase. One of many predictions based on this model is that cells differentiating in the presence of glucose will produce sorocarps with an abnormally high trehalose to cellulose ratio. External perturbation of either the model or of developing cells by glucose increases the levels of sorocarp trehalose and glycogen, 5-fold and 6-fold respectively. Evaluation of the experimental data and the simulation analyses have allowed several predictions to be made concerning the compartmentation of metabolites and the permeability of cells to glucose during differentiation.
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PMID:Fourth expansion and glucose perturbation of the Dictyostelium kinetic model. 55 94

Serum enzymes have not proved useful in evaluation of patients with early colon cancer, but certain enzymes such as transpeptidase, phosphohexone isosomerase, or 5'-nucleotidase have been of assistance in following the course of the disease, particularly in patients with metastatic spread to the liver. Attempts have been made to improve the utility of enzyme analysis in colon cancer by examination of enzyme patterns in colon biopsy specimens, feces, and colon washings. These studies, which will be summarized, are of importance in the possible development of diagnostic tools and as probes in the understanding of the etiology of colon cancer. The technical problems in carrying out these assays in humans, as well as the significance of the activity of aryl sulfatase, beta-glucuronidase, beta-glucosidase, lactic dehydrogenase, glucose-6-p-osphate dehydrogenase, and other enzymes will be considered.
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PMID:Enzymes in colon cancer. General information. 76 57


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