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)

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

The multidisciplinary approach of leukemia phenotyping, called multiple marker analysis, led to changes in the classification systems of normal hematopoiesis and leukemic cells, and introduced the use of a biological and functional definition of leukemia, rather than merely morphological-cytochemical descriptions. Two major conclusions can be drawn from the findings of multiple marker analysis: 1) differentiation of leukemia is not abnormal but blocked ("maturation arrest"), and leukemic cells retain normal maturation-linked markers; and 2) no leukemia specific marker could be detected so far. Although leukemic cells show general qualitative features in common with normal cells, some quantitative characteristics of these similar attributes are peculiar to leukemic blasts. Qualitative and quantitative enzymological characteristics help to identify the cell lineage involved and to determine the developmental point at which maturation arrest occurs. The expression of isoenzymes is often linked to the presumptive sequence of developmental stages. Subsets within ALL subtypes showed pronounced modifications in their isoenzyme patterns associated with increasing maturity. Thus, enzyme markers can provide refined definitions of subgroups by biochemical criteria. Based on recent observations using the enzyme markers TdT, adenosine deaminase, 5'-nucleotidase, purine nucleoside phosphorylase, acid phosphatase, and hexosaminidase, a scheme of enzymological expression in the various commonly accepted subtypes of acute lymphoid leukemia and acute nonlymphoid leukemia is presented. Enzyme marker analysis represents a useful tool as an adjunctive method in multiple marker analysis for assessing diagnosis, prognosis, and the evolutionary and pathogenetic mechanisms underlying the spectrum of leukemia subtypes. Furthermore, enzyme marker analysis may provide further insight into certain aspects of the pathobiology of leukemia which might not be elucidated by other methods.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Significance of enzyme markers as a part of multiple marker analysis in leukemia research. 300 Feb 10

Common acute lymphoblastic leukemia antigen detected by radioimmunoassay in the serum of patients with common acute lymphoblastic leukemia was found to be exclusively associated with the pellet of the serum samples obtained by ultracentrifugation at 100,000 X g. The pellets were shown to contain membrane vesicles or fragments which were characterized by electron microscopy and determination of enzymatic activity. The pelleted fragments had an apparent diameter ranging between 60 and 260 nm and showed a trilaminar membrane structure. On freeze-fracture preparations, the fragments with concave profile, corresponding to the external fracture face of plasma membrane, displayed an intramembrane particle density (ranging from 0 to 750 particles per micron2) which is similar to that recorded on the corresponding fracture face of intact cells from the common lymphoblastic leukemia antigen positive leukemic cell line (Nalm-1) or of vesicles shed in the culture medium by Nalm-1 cells. Furthermore, analysis of the membrane enzyme marker 5'-nucleotidase in the pellet of patient's sera, showed that the presence of this enzyme correlated with that of common lymphoblastic leukemia antigen, but the quantitative relationship between the two surface constituents was not linear. The results suggest that the two markers are located on the same membrane fragments, but that their individual distribution on the shed fragments is heterogeneous.
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PMID:Characterization of membrane vesicles circulating in the serum of patients with common acute lymphoblastic leukemia. 302 64

The status of three purine pathway enzymes, adenosine deaminase, 5'-nucleotidase, and purine nucleoside phosphorylase, was evaluated in the leukemic cells of patients with acute lymphoblastic leukemia and correlated with routine immunological cell surface markers. A distinct pattern of enzyme activity was noted in T-lymphoblasts which have significantly higher adenosine deaminase activity (p less than 0.02) and lower 5'-nucleotidase (p less than 0.001) and purine nucleoside phosphorylase (p less than 0.01) activities than do non-T, non-B lymphoblasts. This enzyme pattern is similar to that observed in normal human thymocytes but is not shared by the mature, normal T-lymphocytes of peripheral blood, suggesting that it may reflect the differentiation status of malignant T-lymphoblasts. These findings, which confirm the biochemical heterogeneity of acute lymphoblastic leukemia, may provide an avenue for selective chemotherapy of this disease.
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PMID:Purine pathway enzyme abnormalities in acute lymphoblastic leukemia. 627 95

Leukemic cells incubated in vitro with 2'-deoxyadenosine (dAdo) plus an inhibitor of adenosine deaminase, 2'-deoxy-coformycin (DCF), show different metabolic responses depending on the histologic and immunologic type of the leukemia. Leukemic cells were obtained from 54 patients with acute lymphoblastic leukemia (ALL), 9 with myeloid or nonlymphoblastic leukemia, 3 with chronic lymphocytic leukemia (CLL), and 3 with lymphoma. There was a wide variation in the LD50, the concentration of dAdo that caused 50% inhibition of the incorporation of 3H-thymidine into cells in the presence of 20 microM DCF. T-cell leukemia specimens were much more sensitive to dAdo than were specimens of pre-B-ALL and null-ALL. In leukemic cells that had been incubated with 14C-dAdo plus DCF, a good correlation was observed between the LD50 and the ratio of 14C-deoxyATP to ATP (correlation coefficient for the fit to a hyperbola = 0.853). The accumulation of deoxyATP by the leukemic cell specimens was correlated best with the activity of ecto-ATPase, less well with cytoplasmic 5'-nucleotidase and deoxyadenosine kinase, and poorly with adenosine deaminase and ecto-5'-nucleotidase. The clinical response to DCF therapy of a patient with T-ALL and another with pre-B-ALL was consistent with the in vitro metabolic response of their cells to DCF and dAdo.
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PMID:Biochemical correlates of the differential sensitivity of subtypes of human leukemia to deoxyadenosine and deoxycoformycin. 628 41

High levels of the ectozyme 5'-nucleotidase (5'-N) and the common ALL-antigen (cALLA) are coexpressed on leukemic blast cells in common ALL, in the lymphoid blast crisis of CML and also on the lymphoblastoid cell-line Nalm-1. Clinically this coexpression can help to subclassify leukemias and may be of diagnostic and prognostic significance. In an attempt to study the mechanism underlying this simultaneous expression plasmamembrane subfractionation was undertaken on Nalm-1. When membrane-shedding from intact cells is induced by sublytic concentrations of the lysophosphatidyl-choline analogue ET-12-H, membrane subfractions are obtained which contain 30-40% of total cellular 5'-N, which is most of the enzyme carried on the cell surface, in a highly enriched form. Under these conditions only a very low release of intracellular enzymes is observed. On the other hand cALLA is not accumulated in these membrane fractions to any appreciable extent. The predominant part of this antigen is still on the intact cells remaining after the shedding procedure. It is concluded that the simultaneous expression of 5'-N and cALLA on Nalm-1 and leukemic blasts is not regulated by a physical association or a close neighborhood of these antigens on the membrane level.
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PMID:Independent expression of the surface markers 5'-nucleotidase and cALLA on leukemic cells. 629 37

5'-Nucleotidase activity of normal human embryonic lung fibroblasts (IMR-90) was found to be inhibited by the homogenates of seven different cell lines originated from patients with different kinds of leukemia and of fresh lymphocytes from a patient with Sezary syndrome (circulating T-cell lymphoma). About 97% of the inhibiting activity was found in the soluble fraction of RPMI 8402 cells, a cell line originated from the lymphocytes of a patient with acute lymphocytic leukemia. This inhibiting activity was not destroyed by dialysis, heating at 56 degrees C for 30 min, nor digestion with RNAase or DNAase. About 85% of the inhibiting activity was destroyed by digestion with papain at 37 degrees C for 1 h and it was destroyed completely by heating at 100 degrees C for 30 min. When the heated (56 degrees C for 30 min) soluble fraction of RPMI 8402 cells was mixed with the homogenate of IMR-90 cells, it had no effect on the activities of alkaline, neutral or acid phosphatases, nor of N-acetyl-beta-D-glucosaminidase or cytochrome c oxidase of IMR-90 cells. Preincubating the mixed samples for 1, 20 and 45 min, respectively, before adding the substrate, the heated soluble fraction of RPMI 8402 cells did not increase the percentage of inhibition for 5'-nucleotidase of the homogenate of IMR-90 cells. No inhibition of other enzyme activities was observed under similar conditions. These data suggest that the inhibiting activity is due to a protein(s) that is not a protease. The inhibiting activity was found in a single peak after the soluble fraction was fractionated by Sephadex G-100 chromatography and sedimentation centrifugation. The molecular weight of the inhibitor was found to be approx. 35,000 by comparing its retention volume and sedimentation rate with those of proteins of known molecular weight. The present study suggest that the previously reported undetectability of 5'-nucleotidase in permanent cell lines could be due to the presence of a protein inhibitor for 5'-nucleotidase in these human leukemic cell lines. It also supports the hypothesis that the increased 5'-nucleotidase activity in normal senescent cells in vitro may be a control in cellular aging that is missing from leukemic cells in vitro.
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PMID:Implications of a 5'-nucleotidase inhibitor in human leukemic cells for cellular aging and cancer. 630 89

The common acute lymphoblastic leukemia antigen (CALLA) has been detected in biological fluids using a radioimmunoassay based on the inhibition of binding of 125I-labeled monoclonal anti-CALLA antibody to glutaraldehyde-fixed NALM-1 cells. With this assay, we showed first that CALLA was released in culture fluids from NALM-1 and Daudi cell lines but was absent from culture fluids from CALLA negative cell lines. Then, we found that the sera of 34 out of 42 patients (81%) with untreated common acute lymphoblastic leukemia (c-ALL) contained higher CALLA levels than any of the 42 serum samples from healthy controls. The specificity of these results was further demonstrated by testing in parallel the sera from 48 patients with CALLA negative leukemias, including 26 acute myeloid leukemia (AML), 12 T-cell acute lymphoblastic leukemia (T-ALL), and 10 acute undifferentiated leukemia (AUL). All of these sera gave negative results, except for one patient with AUL, who had a significantly elevated circulating CALLA level, and one patient with AML, who had a borderline CALLA level, 3 SD over the mean of the normal sera. Preliminary results suggest that circulating CALLA is associated with membrane fragments or vesicles, since the total CALLA antigenic activity was recovered in the pellet of the serum samples centrifuged at 100,000 g. In addition, the CALLA-positive pellets contained an enzyme considered as a membrane marker, 5'-nucleotidase. Evaluation of the clinical importance of repeated serum CALLA determinations for the monitoring of c-ALL patients deserves further investigation.
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PMID:Detection of the common acute lymphoblastic leukemia antigen in the serum of leukemia patients. 633 3

Changes in levels of purine degradative enzymes have been shown to occur during T-cell maturation in both rats and humans with a fall in adenosine deaminase (ADA) and a rise in purine nucleoside phosphorylase (PNP) and 5'-nucleotidase (5'NT) activities. We have investigated the effects of four thymic factors: thymosin fraction 5 (TMS-F5); thymosin alpha 1 (TMS-alpha 1); thymopoietin pentapeptide (TP-5); and thymic conditioned medium (CM) on TdT activity, purine enzyme levels and the phenotypic markers OKT3 (a marker for mature T cells) and NA1/34 (which reacts with immature cortical thymocytes) in human thymocytes and in the lymphoid leukaemic cell lines RPMI-8402 and JM1 (derived from Thy-ALL). All four thymic factors caused one or more maturation change in human thymocytes, e.g. TMS-F5 caused a significant increase in OKT3 expression, TMS-alpha 1 a fall in TdT and ADA activities and a rise in OKT3-positive cells, TP-5 an increase in PNP and CM a rise in 5'NT activity. TMS-F5 also caused a marked elevation of 5'NT in both the T lymphoblastic lines (P less than 0.001). On the other hand the non-physiological phorbol ester, 12-O-tetradecanoyl phorbol acetate (TPA), a tumour promotor with potency of inducing differentiation in some leukaemic cell lines, induced changes in both normal thymocytes and in the leukaemic line JM1 were inconsistent with maturation, e.g. a fall in the percentage of OKT3 cells. These observations suggest that maturation of normal thymocytes might proceed stepwise, each step requiring at least one of the thymic hormones. Although thymosin also induces differentiation changes in a malignant lymphoid line, the pattern of these differs from that induced in their normal counterparts.
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PMID:Biochemical and immunological differentiation of human thymocytes induced by thymic hormones. 660 5

The relative levels of the deoxycytidine kinase (dCK), deoxyguanosine kinase (dGK), and the 5'-nucleotidase (5'-NT) are of importance for the effect of many nucleoside analogues used in the treatment of hematological malignancies. To elucidate dCK, dGK and 5'-NT gene expressions in cell lines and in samples from patients with leukemia, we have established a real-time quantitative PCR (RQ-PCR) method. From the available dCK, dGK and 5'-NT cDNA sequences we designed specific primers and fluorogenic probes for the respective genes. The mRNA of dCK, dGK and 5'-NT was also measured by semi-quantitative RT-PCR, the enzyme activities by a radioactive substrate-based technique and Western blot was used to measure the amount of dCK and dGK protein. A MOLT-4 wild-type and its 9-beta-D-arabinofuranosylguanine (Ara-G)-resistant subline was used for the methods comparisons and the RQ-PCR assay was used in 35 samples from pediatric patients with ALL and AML. The results from RQ-PCR for the cell lines were in agreement with the semi-quantitative RT-PCR. The mRNA expression for dCK, dGK and 5'-NT (expressed as the ratio of the respective gene and the reference gene) in pediatric ALL and AML patients showed a large interindividual variability from 0.06 to 2.34, non-detectable to 0.06 and 0.04 to 0.30, respectively. These results show that the quantitative evaluation by RQ-PCR is a valuable tool in the determination of dCK, dGK and 5'-NT mRNA levels in cell lines and in clinical samples which were expressed at various levels. This rapid, convenient and specific method is suitable for further studies of these genes in clinical samples.
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PMID:Real-time quantitative PCR assays for deoxycytidine kinase, deoxyguanosine kinase and 5'-nucleotidase mRNA measurement in cell lines and in patients with leukemia. 1189 43


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