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)

Membrane vesicles can be prepared from murine lymphoid cells by nitrogen cavitation and fractionated by sedimentation through nonlinear sucrose density gradients. Two subpopulations of membrane vesicles, PMI and PMII, can be distinguished on the basis of sedimentation rate. The subcellular distribution of adenylate and guanylate cyclases in these membrane subpopulations have been compared with the distribution of a number of marker enzymes. Approximately 20-30% of the total adenylate and guanylate cyclase activity is located at the top of the sucrose gradient (soluble enzyme), the remainder of the activity being distributed in the PMI and PMII fractions (membrane-bound enzyme). More than 90% of the 5'-nucleotidase and NADH oxidase activities detected in lymphoid cell homogenates are located in PMI and PMII fractions, whereas succinate cytochrome c reductase activity is detected only in the PMII fractions. In addition, beta-galactosidase activity is distributed in the soluble and PMII fractions of the sucrose density gradients. On the basis of the fractionation patterns of these various enzyme activities, it appears that PMI fractions contain vesicles of plasma membrane and endoplasmic reticulum, whereas PMII fractions contain mitochondria, lysomes, and plasma membrane vesicles. Approximately 30-40% of the adenylate and guanylate cyclase activities in PMII can be converted to a PMI-like form following dialysis and resedimentation through a second nonlinear sucrose gradient. Adenylate and guanulate cyclases can be distinguished on the basis of sensitivity to nonionic detergents.
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PMID:The subcellular distribution of adenylate and guanylate cyclases in murine lymphoid cells. 0 90

The use of enzymes as markers of T or B cells in tissue sections has been studied in mouse lymphoid tissue and lymph nodes from the gerbil, rat and cat. Lymphocytes in the T-cell areas of murine lymph nodes and spleen contained discrete dots of non-specific esterase and N-acetyl-beta-D-glucosaminidase (beta-glucosaminidase) activity, with weak acid phosphatase activity. Lymphocytes in the B-cell areas lacked this discrete staining. Cortical thymocytes contained slight esterase activity while medullary thymocytes were strongly positive for both esterase and beta-glucosaminidase. Lymphocytes with a T-cell staining pattern were only occasionally seen in lymph nodes from Nude (nu/nu) mice. ATPase staining was restricted to lymphocytes in the B-cell areas; weak 5'-nucleotidase staining was only present in a frew lymphocytes in both T- and B-cell areas. Blast cells stimulated by in vivo injection of ConA or PHA in the mouse showed strong discrete enzyme activity for non-specific esterase and beta-glucosaminidase. Lipopolysaccharide-stimulated blast cells and cells within germinal centres lacked this discrete staining. Comparison of lymph nodes from the gerbil, rat and cat suggested at least on enzymes as a T-cell marker in each species although considerable variation in staining profiles was seen in the different species.
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PMID:Cytochemical identification of T and B cells in situ in mouse lymphoid tissue and lymph nodes from the rat, gerbil and cat. 8 10

Three parts were distinguished by electron microscopy and by enzyme histochemistry at the boundary zone between the white and red pulp of the human spleen. The first was the inner layer of the perifollicular region, composed of medium-sized lymphocytes with abundant free ribosomes in their cytoplasm. A small number of reticulum cells intervened among these lymphocytes. This inner layer was considered to correspond to the "Follikelaussenzone" (Strasser). The second was the outer layer of the perifollicular region, composed of a meshwork of reticulum cells with reticular fibers, and sheathed and non-sheathed arteries. Small and medium-sized lymphocytes, granulocytes, erythrocytes, platelets, and a small number of plasma cells were observed in the mesh spaces. This outer layer was considered to correspond to the "marginal zone" (Snook). At the outermost part of this layer, the venous sinus appeared. There was no distinct border between this layer and the red pulp. The third was the neighboring region of the periarterial lymphoid sheath, showeing similar structure and cellular components to the outer layer of the perifollicular region. It was characteristic feature for the lymphocytes and some of the reticulum cells of this region to have a strong activity for alkaline phosphatase reaction, while the lymphocytes of the outer layer showed only a weak activity. Adenosine triphosphatase and 5'-nucleotidase activities were demonstrated on the lymphocytes of these three parts of the boundary zone as well as the lymph follicle. Different activities for these enzyme reactions may indicate the functional properties of the B-cell system.
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PMID:An electron microscopic and enzyme histochemical study of the boundary zone between the white and red pulp of the human spleen. 14 41

Rat lymphocyte populations were assessed for 5'-nucleotidase activity by both biochemical and histochemical methods. Enzyme-specific activity was enriched in lymphocyte plasma membrane fractions and was higher in lymph node and spleen lymphocytes than in thymocytes. Histochemical reactions on sections of spleen and lymph node revealed strong activity in the thymus-dependent regions, periarteriolar lymphoid sheath in spleen, and paracortex in lymph node; whereas the thymus-independent regions, follicles, and germinal centers were negative. In cellular depletion experiments, with three different methods to detect 5'-nucleotidase, it was observed that the depletion of T cells, but not B cells, was accompanied by a loss of enzyme activity and a decrease in the percentage of nucleotidase-positive cells. The results suggest that, among members of the lymphocyte series, high 5'-nucleotidase activity is selectively associated with the plasma membranes of peripheral T cells in the rat.
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PMID:5'-Nucleotidase activity in subpopulations of rat lymphocytes. 30 99

2',3'-Dideoxyguanosine (ddGuo) is a selective inhibitor of the replication of human immunodeficiency virus in vitro and the most active antihepadnavirus nucleoside analog known in vitro and in vivo, in a Peking duck model. However, the exact route by which this and related guanosine analogs are anabolized to their putative active metabolites in target cells is controversial. The anabolic pathway for the activation of ddGuo was investigated with the use of mutant human lymphoid CCRF-CEM and WI-L2 cell lines deficient in known nucleoside kinases. Uptake of ddGuo by human lymphoid cells and subsequent conversion to mono-, di-, and triphosphorylated metabolites is dose dependent and occurs proportionately to the exogenous concentration of drug. Studies with kinase-deficient CCRF-CEM and WI-L2 mutants revealed that at least two different routes of metabolism are operating in these cells to initiate the phosphorylation of ddGuo to its active dideoxynucleotides, one being deoxycytidine (dCyd) kinase and the other a cytosolic-5'-nucleotidase acting in the anabolic direction as a phosphotransferase. The evidence for this included 1) a lower but significant accumulation of drug anabolites in dCyd kinase-deficient mutants, 2) a lack of cross-resistance of the kinase-deficient mutants to growth inhibition by ddGuo, compared with that by the related analogs dideoxycytidine and arabinosylcytosine, known substrates for dCyd kinase, and 3) identification of different phosphorylation activities for ddGuo in extracts of wild-type cells and kinase-deficient mutants. Knowledge of the enzyme systems involved in anabolism of ddGuo analogs should be important for both new drug design and optimal therapeutic application.
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PMID:Metabolic pathways for the activation of the antiviral agent 2',3'-dideoxyguanosine in human lymphoid cells. 132 48

Aggregates of lymphocytes were demonstrated from 70 days gestation (term 150 days in sheep) in the proximal colon and rectum. Immunoperoxidase staining for 5'-bromo-2'-deoxyuridine incorporation and IgM, indicated that the lymphocyte population of lymphoid follicles in fetal sheep colon was actively dividing and surface IgM positive. Enzyme histochemistry for 5'-nucleotidase showed that the lymphocytes developed in a meshwork of positive reticular cells, suggestive of developing follicles. Follicle aggregates were distributed in a characteristic pattern in lambs, with major accumulations in the ascending colon and in the rectum. In adult sheep a partial atrophy of follicle aggregates was observed. The microscopic structure of large intestinal aggregates showed similarities to the jejunal Peyer's patch (PP), with broad follicles containing a prominent corona and wide interfollicular areas in older lambs. The apparent deep penetration of crypts into the lymphoid tissue proper, which is a frequently reported phenomenon for colon follicles, was dependent on the contractile state of the mucosa, as judged from its absence in specimens where the intestinal wall had been stretched before fixation.
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PMID:Ontogeny, distribution and structure of aggregated lymphoid follicles in the large intestine of sheep. 177 64

Carbovir (CBV) is a highly selective carbocyclic nucleoside inhibitor of HIV replication in human lymphocytes and is potentially useful in the treatment of AIDS [Vince et al. (1988) Biochem. Biophys. Res. Commun. 156, 1046-1053]. Using human lymphoid cells severely deficient in nucleoside kinases, we were able to identify the route of activation of CBV metabolism. The present studies have demonstrated that CBV is anabolized to the mono-, di-, and triphosphates and to guanosine 5'-triphosphate in CCRF-CEM cells. Conversion to GTP amounted to 15-20% of the total analogue nucleotides formed in the cells and may arise from CBV through depurination and salvage via HGPRT. Evidence was obtained that neither deoxycytidine kinase, adenosine kinase, or mitochondrial deoxyguanosine kinase is primarily involved in the initial step of phosphorylation of CBV in CCRF-CEM cells. In contrast, earlier studies [Johnson & Fridland (1989) Mol. Pharmacol. 36, 291-295] showed that a cytosolic 5'-nucleotidase catalyzes the activation of CBV to the monosphosphate. Other biochemical effects examined showed that the nucleobases hypoxanthine and adenine, but not guanine, their respective nucleosides, and the dideoxynucleosides 2',3'-dideoxyinosine, 2',3'-dideoxyguanosine, and 3'-azido-3'-deoxythymidine produced significant increased accumulation of CBV nucleotides in CEM cells. The exact mechanism for this potentiation of CBV phosphorylation has not been elucidated but may be due to a modulating effect of intracellular nucleotides on 5'-nucleotidase activity.
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PMID:Metabolism of the carbocyclic nucleoside analogue carbovir, an inhibitor of human immunodeficiency virus, in human lymphoid cells. 227 22

A combined histologic, immunohistologic, enzyme histochemical, and immunologic study has been carried out in a 7-year-old girl with recurring extramediastinal monocentric giant lymph node hyperplasia of hyaline-vascular type. A large panel of monoclonal and polyclonal antibodies to lymphoid and nonlymphoid cell markers were tested on frozen and paraffin-embedded lymph node tissue as well as on cell suspension and peripheral blood. Tissue enzyme histochemical study, including a conventional hematologic panel, was performed on frozen and plastic-embedded sections. The pattern was dominated by nodular aggregates of round BA-1+ Leu-14+ HLA-DR+ ATPase+ lymphocytes with polyclonal sIgD and sIgM positivity and lacking cIg and BA-2 staining. Leu-1+/Leu-4+, OKT6+, OKT10+, Leu-7+, and CALLA+ cells were few or absent in the nodules, whereas DRC-1+ BA-2+ HLA-DR+ 5'-Nuc+ cells formed a dendritic network in the outer portion of the nodules. No immunoreactivity for lymphoid and nonlymphoid cell markers, including cytokeratin and keratin, was detected in centrinodular histiocytic-like cells. Particularly, the Hassall's-like structures contained a target-like positivity for laminin, and consisted of flattened acid phosphatase (AP), alpha-naphthyl acetate esterase (ANAE), 5'-nucleotidase (5'-Nuc), and adenosine triphosphatase (ATPase) positive cells, whose enzyme profile overlapped with that of the histiocytic-like cells. The extranodular areas were mainly composed of Leu-1+/Leu-4+ lymphocytes with Leu-3a+/OKT4+ phenotype and, to a lesser extent, of OKT6+ OKT10+ lymphoid cells and scattered cells with markers of histiocytic lineage. The abundant vascular component was generally identified by laminin positivity and, in smaller proportion, it was positive for Factor VIII-related antigen. Most of the medium-sized vessels with high endothelium had marked AP, ANAE, and ATPase activities. The process observed resulted from vascularized nodular aggregates of nontransformed B-cells with the phenotype of primary follicle lymphocytes, associated to centrinodular histiocytic-like cells with a distinct enzyme profile.
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PMID:Immunohistochemical, enzyme histochemical, and immunologic features of giant lymph node hyperplasia of the hyaline-vascular type. 242 88

2',3'-Dideoxyinosine (ddlno) is a potent and selective inhibitor of human immunodeficiency virus in human lymphoid cells and monocytes/macrophages. Earlier studies [J. Biol. Chem. 263:15354 (1988)] showed that anabolism of ddlno in human lymphoid cells is mediated via an initial step of phosphorylation and subsequent amination to dideoxy-AMP via adenylosuccinate synthetase/lyase. Evidence was obtained that neither adenosine kinase nor deoxycytidine kinase is involved in the phosphorylation of this compound in human lymphoid cells. We now find that, in the presence of MgCl2, KCl, and inosine-5'-monophosphate as phosphate donor, purified cytosolic 5'-nucleotidase catalyzed the phosphorylation of ddlno. Although not phosphate donors, ATP, diadenosine tetraphosphate, and glycerate-2,3-bisphosphate stimulate this phosphorylation by the nucleotidase 4-5-fold. In addition to ddlno, the antiviral nucleoside analogs 2',3'-dideoxyguanosine and carbovir were substrates for this enzyme. The relative phosphorylation of these compounds varied with the concentration of the phosphate donor IMP. Approximate Km values of the nucleotidase for inosine, ddlno, dideoxyguanosine, and carbovir were, respectively, 3.4, 0.5, 0.9, and 1.7 mM. Although the substrate activity of dideoxynucleosides is inefficient, it appears likely that this nucleotidase is responsible for the metabolism of these compounds to their active nucleotides, yielding antiviral activity in human lymphoid cells.
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PMID:Phosphorylation of 2',3'-dideoxyinosine by cytosolic 5'-nucleotidase of human lymphoid cells. 254 85

Ectoenzyme activities were determined in peripheral blood cells from patients with acute leukemias, from normal controls, and in cells of hematopoietic cell lines. In common acute lymphoblastic leukemia, cell membrane-associated 5'-nucleotidase (5'-N) activity was significantly higher than in acute T and unclassified lymphoblastic leukemias. In acute myeloblastic and myelomonocytic leukemias, cells contained significantly higher gamma-glutamyl transpeptidase (gamma-GT) activity than in lymphoblastic leukemias. Normal B lymphocytes differed from T cells and monocytes mainly in their 5'-N activity, whereas in monocytes, gamma-GT activity was more pronounced than in other normal blood cells. Hematopoietic cell lines showed some distinct patterns of ectoenzyme activity. Most B cell lines had high 5'-N and (Na-K-Mg) adenosine triphosphatase activities. In lines of myeloid origin, elevated gamma-GT values were found. In lymphoid stem cells and in T lymphoblast lines, most ectoenzyme activities were lower than in the other cell lines. In some cell lines, characteristic high-activity marker enzymes were detected.
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PMID:Determination of ectoenzyme activities in leukemic cells and in established hematopoietic cell lines. 286 54


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