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)

Acute renal failure was induced in male rats by the subcutaneous injectioon of 4 mg HgC12 per kg body weight. Enzyme activities of the proximal tubule were studied histochemically at six time intervals from 15 min to 24 h. The enzyme studied were alkaline phosphatase, 5'-nucleotidase, acid phosphatase, alpha-glycerophosphate dehydrogenase (NAD-independent), malic dehydrogenase, succinic dehydrogenase, latic dehydrogenase, glucose-6-phosphate dehydrogenase and glucose-6-phosphatase. Decreases in activity were observed for alkaline phosphatase and 5'-nucleotidase after 15 min. Acid phosphatase was decreased after 30 min. These three enzymes returned to control levels after 3 h, but malic dehydrogenase and alpha-glycerophosphate dehydrogenase were decreased at this time interval. Succinic dehydrogenase was first decreased after 6 h. The earliest morphological changes detectable by light microscopy were observed in pars recta tubules in the medullary rays after 6 h, a time when all enzymes studied showed widespread decreased activity throughout the proximal tubule. After 24 h, the pars convoluta appeared morphologically normal but the pars recta was necrotic and exhibited calcification, whereas enzyme activity was decreased (absent in some cases) in both pars convoluta and pars recta. These results support the hypothesis that Hg++, when given in a sublethal dose, is associated with early histochemical changes in the brush border of the proximal tubule, which may be related to early changes in sodium reabsorption and to the subsequent development of acute renal failure. The observation that changes in plasma membrane-associated enzymes occur early and prior to alterations in enzymes of mitochondria and the endoplasmic reticulum suggests that Hg++ interacts initially with the plasma membrane.
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PMID:Studies on the pathophysiology of acute renal failure. II. A histochemical study of the proximal tubule of the rat following administration of mercuric chloride. 18 27

Highly purified nuclei isolated from bovine corpora lutea showed marked enrichment of NAD pyrophosphorylase, a marker for this organelle. Rough endoplasmic reticulum and lysosomal markers were undetectable, whereas plasma membrane and Golgi markers were detectable but not enriched in nuclei. These highly puridied nuclei exhibited specific binding with 125I-labeled human choriogonadotropin, [3H]prostaglandin E1 and [3H]prostaglandin F2 alpha. However, these bindings were only 15.4% (human choriogonadotropin), 7.9% (prostaglandin E1) and 8.9% (prostaglandin F2 alpha) of the plasma membrane binding observed under the same conditions. Washing of nuclei and plasma membranes twice with buffer containing 0.1% Triton X-100 resulted in gonadotropin and prostaglandin F2 alpha binding site and 5'-nucleotidase (EC 3.1.3.5) losses from nuclei that were different from those observed for plasma membranes. More importantly, the washed nuclei exhibited 44% (human choriogonadotropin), 21--26% (prostaglandins) of original specific binding despite virtual disappearance of 5'-nucleotidase activity. The nuclear membranes isolated from nuclei, specifically bound 125I-labeled human choriogonadotropin and [3H]prostaglandin F2 alpha to the same extent or significantly more ([3H]prostaglandin E1, P less than 0.05) than nuclei themselves, despite the marked losses of chromatin. In summary, our data suggest that gonadotropin and prostaglandins bind to nuclei and that this binding was intrinsic and was primarily associated with the nuclear membrane.
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PMID:Gonadotropin and prostaglandins binding sites in nuclei of bovine corpora lutea. 22 42

A method is described for the isolation of secondary lysosomes from homogenates of rabbit liver; The uptake of Triton WR-1339 by rabbit-liver lysosomes when administered by intraperitoneal injection was used to decrease the density of secondary lysosomes. Lysosomal fractions prepared by this method contain an NAD nucleosidase (NAD glycohydrolase, EC 3;2.25), an enzyme which has previously been considered to be associated with other subcellular fractions. The enzyme has maximum activity at pH 6 and cleaves both NAD and NADP. It is inhibited by nicotinamide (Ki equals 4.5 mM) and by HgCl2. Both nucleosidase and 2'-nucleotidase show in-vitro latency typical of lysosomal acid hydrolases. Rabbit-liver plasma-membrane fractions were isolated which contained most 5'-nucleotidase but relatively little nucleosidase, whereas rabbit liver lysosomes contain both 5'-nucleotidase and nucleosidase enzymes but little adenyl cyclase.
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PMID:Evidence for NAD nucleosidase in rabbit-liver lysosomes. 23 77

The enzyme activity of Mg++-ATPase, Na+-K+-ATPase, 5'-nucleotidase and NAD(P)H-oxidase was cytochemically detected at the ultrastructural level in mouse peritoneal macrophages infected with untreated and with specific antibody-coated Toxoplasma gondii tachyzoites. The Mg++-ATPase and 5'-nucleotidase were distributed throughout the macrophages' plasma membrane but were not observed in the membrane lining endocytic vacuoles containing ingested parasites; however, Na+-K+-ATPase activity was detected in the macrophages' plasma membrane as well as in the parasitophorous vacuoles that contained untreated or specific antibody-coated parasites. Reaction product, indicative of NAD(P)H-oxidase, was detected in the parasitophorous vacuoles that contained only specific antibody-coated parasites.
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PMID:Cytochemical localization of plasma membrane enzyme markers during interiorization of tachyzoites of Toxoplasma gondii by macrophages. 254 39

An enzyme with FAD pyrophosphatase activity was extracted from human placental syncytiotrophoblast microvilli and purified to near-homogeneity. The enzyme has been identified as 5'-nucleotidase by several criteria. Throughout purification, parallel increases in the specific activities of FAD pyrophosphatase and AMP phosphatase were observed. The enzyme was a glycoprotein with a subunit molecular weight of 74,000. EDTA treatment resulted in a marked decline in both activities, and restoration of FAD pyrophosphatase activity but not 5'-nucleotidase activity was accomplished by the addition of Co2+ or, to a lesser extent, Mn2+. The substrate specificity of the 5'-nucleotidase activity that we observed agreed closely with the results of others. The pyrophosphatase activity was relatively specific for FAD. ADP, ATP, NAD(H), and FMN were not hydrolyzed, and ADP strongly inhibited both activities. For FAD pyrophosphatase activity, a Km of 1.2 x 10(-5) M and a Vmax of 1.1 mumol/min/mg protein were determined in assays performed in the presence of Co2+. In the absence of added Co2+, the Vmax declined but the Km was unchanged. For 5'-nucleotidase (AMP as substrate) the Km was 4.1 x 10(-5) M and the Vmax 109 mumol/min/mg protein. Hydrolysis of FMN to riboflavin was observed in partially purified detergent extracts of microvilli that contained alkaline phosphatase activity and lacked FAD pyrophosphatase and 5'-nucleotidase activity. The presence of both FAD pyrophosphatase and FMN phosphatase activities in syncytiotrophoblast microvilli supports the view that the placental uptake of vitamin B2 involves the hydrolysis of FAD and FMN to riboflavin which is then absorbed, a sequence postulated for intestinal absorption and liver uptake.
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PMID:5'-Nucleotidase of human placental trophoblastic microvilli possesses cobalt-stimulated FAD pyrophosphatase activity. 284 89

Nicotinamide mononucleotide (NMN) is not only an intermediate for the biosynthesis but also a degradation product of pyridine cofactors in animal tissues. Among the animal tissues tested, the highest NMN catabolizing activity was detected in beef liver (5.6 mumol/min/g tissue). This activity was 16 times higher than the NAD hydrolysis catalyzed by the liver NAD glycohydrolase. As a result of enzymatic analysis of the NMN splitting process, two types of enzyme responsible for this catabolism were partially purified and identified as a membrane-bound 5'-nucleotidase and a cytoplasmic nicotinamide riboside (NR) phosphorylase. No specific NMN glycohydrolase could be found in contrast to results observed in bacterial systems. The 5'-nucleotidase and NR phosphorylase constitute an obligatory process of the pyridine nucleotide cycle. The dephosphorylation and phosphorolysis catalyzed suggest that these enzymes could serve as an important mechanism for salvaging the ribose and nicotinamide moieties of NMN and pyridine nucleotides in the cell and a process that could be regulated at the mononucleotide level by this "NMN cycle" rather than by a NAD glycohydrolase cycle. In addition to the enzymatic properties of these enzymes, a regulatory mechanism by nucleotides such as ATP was also demonstrated.
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PMID:Metabolism of nicotinamide mononucleotide in beef liver. 303 59

The process of interaction between macrophages and promastigote and amastigote forms of Leishmania mexicana amazonensis was analyzed using freeze fracture and cytochemistry. The promastigotes inside endocytic vacuoles of macrophages presented an altered distribution of intramembranous particles and a wavy aspect of the plasma membrane. However, amastigotes did not show such alterations. The membrane alterations are probably caused by intracellular cell lysis of the promastigotes by the macrophages. An accumulation of intramembranous particles was seen in the plasma membrane of amastigote forms in the area of adhesion to the macrophages. The parasitophorous vacuole membrane had intramembranous particles randomly distributed. The enzyme activity of Mg++-ATPase, 5'-nucleotidase and NAD(P)H-oxidase was cytochemically detected, at the ultrastructural level, in normal mouse peritoneal macrophages and in macrophages infected with Leishmania mexicana amazonensis. Mg++-ATPase and 5'-nucleotidase are uniformly distributed throughout the macrophage's plasma membrane but were not detected in the membrane lining endocytic vacuoles containing ingested parasites (parasitophorous vacuole). NAD(P)H-oxidase activity was seen in those portions of the macrophage's plasma membrane which enter in direct contact with parasites and also in association with the membrane of the parasitophorous vacuole. The amount of reaction product, indicative of NAD(P)H-oxidase activity, was larger in macrophages which interacted with the promastigote than in those which interacted with the amastigote form of L. mexicana amazonensis. Concanavalin A binding sites and anionic sites of the macrophage's surface, labeled before the interaction, are not interiorized together with the parasites, however, are observed in endocytic vacuoles which do not contain parasites.
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PMID:Freeze-fracture and cytochemistry study of the interaction between Leishmania mexicana amazonensis and macrophages. 337 Jun 24

The isolation of plasma membrane from human peripheral blood monocytes is described. Monocytes were isolated by centrifugal elutriation, to eliminate an adherence step, thus minimizing functional and surface antigenic alterations to the cells. Monocytes were surface-labelled with a radiolabelled monoclonal antibody, 125I-WVH-1, and then disrupted by nitrogen cavitation. Membranes were separated according to equilibrium buoyant density by isopycnic centrifugation on a sucrose gradient. The subcellular membranes were localized using marker enzymes for the plasma membrane, 5'-nucleotidase and leucine 2-naphthylamidase (leucine aminopeptidase), and for intracellular membranes: galactosyltransferase (Golgi), arylsulfatase C (endoplasmic reticulum), monoamine oxidase (mitochondria), catalase (peroxisomes), beta-hexosaminidase and beta-glucuronidase (lysosomal vesicles) and lactate dehydrogenase (cytosol). The monoclonal antibody 125I-WVH-1 was shown to label the plasma membrane, as judged by known markers, and represents a highly specific trace label, applicable to the use of plasma membrane as an immunogen for monoclonal antibody production. The NAD-splitting enzyme, NAD+ nucleosidase, was detected and its presence on the plasma membrane was demonstrated. The subcellular localization of non-specific esterase in human mononuclear phagocytes is controversial. No evidence was found for alpha-naphthyl acetate esterase activity on the plasma membrane or in lysosomal vesicles. However, a membrane-bound esterase in fractions with properties similar to the smooth endoplasmic reticulum was detected.
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PMID:Isolation of plasma membrane from human blood monocytes. Subcellular fractionation and marker distribution. 397 89

1. A mouse liver plasma-membrane preparation was solubilized in an N-dodecylsarcosinate-Tris buffer, pH7.8, and the proteins and glycoproteins were separated by a rate-zonal centrifugation in sucrose-detergent gradients. 2. A peak of alkaline phosphodiesterase activity which sedimented ahead of the 5'-nucleotidase peak was associated with a major glycoprotein component of the plasma membrane. 3. The phosphodiesterase activity was then purified further by gel filtration and gave a single glycoprotein band after electrophoresis on polyacrylamide gels. The apparent molecular weight of the polypeptide at pH7.4 and 8.9 was 128000-130000 and was independent of the polyacrylamide concentration. Electrophoresis in gels containing deoxycholate showed that the protein band was coincident with phosphodiesterase activity. 4. After two-dimensional immunoelectrophoresis, with agarose containing rabbit anti-(mouse plasma-membrane) antiserum as second dimension, the enzyme showed one component which was also coincident with the phosphodiesterase activity. 5. An amino acid composition of the glycoprotein is presented. Carbohydrate analysis indicated the presence of glucosamine, neutral sugars and sialic acid. 6. The enzyme was also a nucleotide pyrophosphatase, as shown by a similar enrichment during purification of activity towards ATP, NAD(+), UDP-galactose and UDP-N-acetylglucosamine. The phosphodiesterase activity, measured by using dTMP p-nitrophenyl ester as substrate, was competitively inhibited by nucleotide pyrophosphate substrates. The enzyme showed little or no activity towards RNA, cyclic AMP, AMP, ADP and glycerylphosphorylcholine. 7. The significance of this enzyme activity in the plasma membrane is discussed.
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PMID:Purification and properties of a mouse liver plasma-membrane glycoprotein hydrolysing nucleotide pyrophosphate and phosphodiester bonds. 436 Feb 50

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


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