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

---

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

Portions of closed jejunal biopsies from the dog were homogenised and their organelles separated by isopycnic centrifugation on continuous sucrose density gradients. The distributions of marker enzymes for the principal organelles were determined using highly sensitive assay procedures. The following organelles, with assayed marker enzymes and modal densities between brackets were characterised: peroxisomes (catalase, 1.21); brush borders (zinc-resistant alpha-glucosidase, leucyl-beta-naphthyl-amidase, gamma-glutamyl transferase, alkaline phosphatase, 1.20); lysosomes (N-acetyl-beta-glucosaminidase, alpha-mannosidase, 1.19); mitochondria (malate dehydrogenase, 1.18); endoplasmic reticulum (Tris-resistant alpha-glucosidase, 1.16); basal-lateral membranes (5'-nucleotidase, 1.11) and cytosol (lactate dehydrogenase). Homogenisation in isotonic sucrose containing digitonin (0.12 mmol/litre) selectively disrupted lysosomes and increased the equilibrium density of brush border and basal-lateral membranes. This procedure will be used to study the subcellular pathology of naturally occurring intestinal disease in the dog.
...
PMID:Subcellular fractionation studies on peroral jejunal biopsies from the dog. 3 Jan 25

Differential centrifugation was applied to adult and foetal liver of monkey. Obtained fractions were: F1 (800 X g); F2 (12 500 X g); F3 (200 000 X g); and cell sap. Analysis of chemical compounds of these fractions shows that: (1) adult and foetal nucleic acids levels are similar; (2) there are more proteins in adult than in foetal hepatocytes; (3) most of the glycogen is located in F3; the foetal level is twenty times higher than the adult level. Plasma membrane enzymes (5'-nucleotidase, adenylate cyclase) show a nucleomicrosomic distribution. The distribution of alkaline phosphatase is not significant. Mitochondrial enzymes (monoamine oxydase, succinate cytochrome c reductase, cytochrome oxydase) are enriched in F2 without any sedimentation in F3. There is more malate dehydrogenase liberated in cell sap during foetal liver fractionation. This indicates the foetal mitochondria are more sensitive to the homogenisation method. Lysosomal enzymes (acid phosphatase, N-acetylglucosaminidase) are enriched in F2. The same observation for N-acetylglucosaminidase as for malate dehydrogenase leads to the same conclusion for foetal lysosomes. Endoplasmic reticulum and Golgi enzymes (glucose-6-phosphatase and related phosphotransferase activity, NADPH-cytochrome c reductase and sialytransferase) are much enriched in F3. Thus this fraction F3 is pure enough to allow the observation of the modification produced on endoplasmic reticulum and Golgi apparatus during foetal and neonatal development.
...
PMID:[Comparative study of microsomal enzymic activities in adult and foetal monkey hepatocytes (author's transl)]. 11 30

As it was shown previoulsy by others, the membrane-bound phosphodiesterase (cyclic adenosine 3':5'-monophosphate phosphodiesterase) of rat epididymal fat cells was stimulated when intact cells were exposed to insulin. The levels of stimulation observed in the present study in the cell homogenate and microsomal fraction were approximately 2.0- to 2.5-fold and 2.5- to 3.0-fold, respectively, when the initial substrate level was 100 nM and insulin concentration was 1 to 3 nM. When the microsomal fraction was subjected to a sucrose density gradient centrifugation, most of the insulin-sensitive phosphodiesterase activity was fractionated into the "light" microsomal fraction which was rich in NADH2:potassium ferricyanide:oxidoreductase) and low in 5'-AMPase, adenylate cyclase, and insulin-binding activities. The latter three activities were mostly fractionated into the "heavy" microsomal fraction. Both basal and insulin-stimulated phosphodiesterase activities were low when cells were homogenized in the presence of N-ethylmaleimide or p-chloromercuribenzoate. The insulin-stimulated enzyme activity was also low when cells were homogenized in the presence of --SH compounds (e.g. dithiothreitol) or certain metal-chelating agents (e.g. ethylene glycol bis(beta-aminoethyl ehter)-N,N'-tetraacetate (EGTA)), or in a nitrogen atmosphere. The effect of EGTA was prevented by the addition of certain heavy metal ions but not by the addition of Ca2+ or Ca2+ plus Mg2+ ions. When cells were homogenized in the presence of certain oxidants (e.g. diamide, sodium tetrathionate, or air), a high plus-insulin activity was observed; this activity was not lowered by subsequent treatment of the enzyme with N-ethylmaleimede, EGTA, or fresh cell homogenate that was prepared in the presence of EGTA. However, the activity of an apparently oxidized enzyme could still be lowered by treatment woth dithiothreitol. A partially purified enzyme in the enzyme in the microsomal fraction was fairly stable both in basal and insulin-stimulated states (fully active after 35 days when kept at -20degrees). EGTA added to the homogenization buffer lowered the basal phosphodiesterase activity, but this effect was reversed by the addition of Ca2+ ions. EGTA also decreased the enzyme activity that was stimulated by norepinephrine. However, neither EGTA nor dithiothreitol had any effect on the activities of 5'-AMPase, NADH-dehydrogenase, and malate dehydrogenase of fat cells. The above data indicate that most of the insulin-sensitive phosphodiesterase and the so-called "cell membrane markers" are associated with different subcellular particles in the cell homogenate. In addition, the data seem to indicate that the insulin-stimulated phosphodiesterase has certain --SH groups and that the activity of the enzyme is stabilized when the --SH groups are oxidized by certain oxidants including molecular oxygen. It is suggested that the air oxidation of the enzyme is catalyzed by a trace of certain heavy metal ions and, therefore, can be blocked by a metal-chelating agent.
...
PMID:Insulin-sensitive phosphodiesterase. Its localization, hormonal stimulation, and oxidative stabilization. 17 Feb 71

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.
...
PMID:The isolation and partial characterization of the plasma membrane from Trypanosoma brucei. 48 94

Mitochondrial and microsomal fractions were isolated from guinea pig myocardium by differential pelleting. The mitochondrial fraction was subjected to analytical subfractionation by sucrose density gradient centrifugation and the gradient fractions assayed for marker enzymes for the various mitochondrial compartments, viz outer membrane (monoamine oxidase), intermembranous space (adenylate kinase), inner membrane (Mg2+-dependent ATPase and cytochrome c oxidase) and mitochondrial matrix (malate dehydrogenase), and for creatine kinase. Both creatine kinase and adenylate kinase were released by suspending the mitochondria in 50 mmol . litre-1 sodium phosphate buffer. Sonication or disruption with the detergent, digitonin released the adenylate kinase but the creatine kinase remained associated with the inner membranes. Subsequent salt treatment desorbed the creatine kinase from these membranes. It is concluded that creatine kinase is located to the outer aspect of the inner mitochondrial membrane. Analytical subfractionation of the microsomal fraction clearly resolved markers for the sarcolemma (5'-nucleotidase), outer mitochondrial membrane (monoamine oxidase) and endoplasmic reticulum (neutral alpha-glucosidase and RNA). Creatine kinase was localised in the endoplasmic reticulum particularly the smooth membranes.
...
PMID:Sub-mitochondrial and sub-microsomal distribution of creatine kinase in guinea pig myocardium. 51 58

1. Fragments (2-20 mg wet wt.) of closed needle-biopsy specimens from human liver were disrupted in iso-osmotic sucrose and subjected to low-speed centrifugation. The supernatant was layered on a linear sucrose-density gradient in the Beaufay small-volume automatic zonal rotor. The following organelles, with equilibrium densities (g/ml) and principal marker enzyme shown in parentheses, were resolved: plasma membrane (1.12-1.14; 5'-nucleotidase); lysosomes (1.15-1.20; N-acetyl-beta-glucosaminidase); mitochondria (1.20; malate dehydrogenase); endoplasmic reticulum (1.17-1.21; neutral alpha-glucosidase); peroxisomes (1.22-1.24; catalase). 2. The distribution of particulate alkaline phosphatase and, to a lesser degree, leucine 2-naphthylamidase followed that of 5'-nucleotidase. gamma-Glutamyltransferase was associated with membranes of significantly higher equilibrium density than was 5'-nucleotidase. 3. The distribution of 12 acid hydrolases was determined in the density-gradient fractions. beta-Glucosidase had a predominantly cytosolic localization, but the other enzymes showed a broad distribution of activity throughout the gradient. Evidence was presented for two populations of lysosomes with equilibrium densities of 1.15 and 1.20 g/ml, but containing differing amounts of each enzyme. Further evidence of lysosomal heterogeneity was demonstrated by studying the distribution of isoenzymes of hexosaminidase and of acid phosphatase. 4. The resolving power of the centrifugation procedure can be further enhanced with membrane perturbants. Digitonin (0.12 mM) selectively disrupted lysosomes, markedly increased the equilibrium density of plasma-membrane components and lowered the density of the endoplasmic reticulum, but did not affect the mitochondria or peroxisomes. Pyrophosphate (15 mM) selectively lowered the equilibrium density of the endoplasmic reticulum.
...
PMID:Analytical subcellular fractionation of needle-biopsy specimens from human liver. 70 96

Merocyanine 540 (MC 540) is a photosensitizing dye that is used clinically for the purging of autologous bone marrow grafts and preclinically for the inactivation of enveloped viruses in blood products. Its mechanism of action is not yet well understood. This paper investigates the sites of MC 540-mediated photodamages in L1210 leukemia cells by examining the effects of MC 540-sensitized photoirradiation on several soluble and membrane-bound marker enzymes. When exposed to MC 540 and white light under a standard set of conditions, the activities of Na+/K(+)-ATPase, Mg2(+)-ATPase, and 5'-nucleotidase (three plasma membrane-bound enzymes) were reduced by 54, 49, and 55%, respectively. None of the intracellular enzymes included in this survey was affected by MC 540-sensitized photoirradiation as long as the plasma membrane remained intact. The two soluble enzymes, lactate dehydrogenase and malate dehydrogenase, remained refractory to MC 540-sensitized photoirradiation even after the plasma membrane had been disrupted. By contrast, the activities of the membrane-bound enzymes, NADPH-cytochrome c reductase and succinate dehydrogenase, were reduced in cell lysates by 55 and 81%, respectively. Purified NADPH-cytochrome c reductase was about 3 times less sensitive than the microsomal enzyme, suggesting that the membrane environment facilitated photoinactivation. The MC 540-sensitized photoinactivation of enzymes was accelerated in the presence of deuterium oxide and inhibited if oxygen in the medium was displaced by nitrogen or azide was added to the medium. Taken together, these data support the view that the plasma membrane is a major target of MC 540-mediated photodamages, that the inactivation of membrane-bound enzymes is an oxidative process, and that at least some photodynamic damages are mediated by type II chemistry.
...
PMID:Merocyanine 540-sensitized photoinactivation of soluble and membrane-bound enzymes in L1210 leukemia cells. 217 31

Microwave-stimulated enzyme incubations for acetylcholinesterase, 5'-nucleotidase, alkaline phosphatase, lactate dehydrogenase, malate dehydrogenase, succinic dehydrogenase and isocitric dehydrogenase were studied, and compared with incubations in a waterbath. Temperature settings of 37 degrees C and 50 degrees C were used, and the incubation times were varied from 30 seconds to 30 minutes. The desired temperature of the incubation solution was reached in the microwave oven within 1 minute, whilst in the waterbath it took 10 to 25 minutes. The microscopic results for alkaline phosphatase and succinic dehydrogenase at a temperature setting of 50 degrees C were superior in the microwave method for incubation times less than 15 minutes. It is postulated that the increased reaction product of alkaline phosphatase and succinic dehydrogenase is due to a temperature effect, which has to be large enough to be of practical value. For the other enzymes studied, microwave-stimulated incubations were no better than the conventional incubations at corresponding temperatures. For 5'-nucleotidase there were aspecific lead deposits in the microwave method. All enzymes performed at the elevated, unphysiological temperature of 50 degrees C proved to have advantages, except for 5'-nucleotidase, whilst for malate dehydrogenase there was an aspecific reduction of the colour developer at this temperature.
...
PMID:Microwave-stimulated brain enzyme incubations are possible at the unphysiological condition of 50 degrees C. 224 28

Quantitatively, the amount of microsomes obtained using dimethyl sulfoxide is larger than that obtained from sucrose solutions (Centelles, Franco & Bozal (1986) Biol. Chem. Hoppe Seyler 367, 461-475). In this paper it is demonstrated that from a qualitative point of view they appeared to be indistinguishable with respect to molecular characteristics. Thus, both types of microsomes had the same behaviour in experiments of isopicnic ultracentrifugation with Percoll, isoelectric focusing and gel permeation. In these experiments, the 5'-nucleotidase, lactate dehydrogenase and malate dehydrogenase activities bound to the microsomal fraction were also studied. Lactate and malate dehydrogenase activities were always found in free and membrane-bound form. In contrast, 5'-nucleotidase activity was always encountered bound to microsomal membranes.
...
PMID:Determination of the characteristics, properties and homogeneity of rat brain microsomes. Binding of lactate dehydrogenase, malate dehydrogenase and 5' nucleotidase to microsomal membranes. 283 90

This study has investigated the potential role of wheat in the pathogenesis of a naturally occurring enteropathy in Irish setter dogs. At eight months on a cereal-containing diet, jejunal biopsies from affected animals exhibited partial villus atrophy, increased intraepithelial lymphocytes, and distinct biochemical abnormalities in the brush border. Activities of alkaline phosphatase and leucyl-2-naphthylamidase were almost undetectable while disaccharidases were unaltered. Activity of 5'-nucleotidase (basolateral membrane) was low, and reduced malate dehydrogenase reflected a loss of mitochondrial activity, but other organelles were unaffected. Recovery was achieved on a wheat-free diet. Relapse on subsequent wheat challenge was characterized by partial villus atrophy and a selective effect on the brush border: modal density was decreased and there was a severe loss of brush-border alkaline phosphatase activity. These findings document a wheat-sensitive enteropathy in Irish setter dogs and suggest that brush-border alkaline phosphatase is specifically susceptible to damage by wheat.
...
PMID:Sequential morphologic and biochemical studies of naturally occurring wheat-sensitive enteropathy in Irish setter dogs. 302 59


1 2 3 Next >>

---