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)

Activities of the ecto-enzymes 5'-nucleotidase (5'-N) and phosphatase were determined on the surface of intact cells from 15 different established lines of human B- and T-lymphoblasts. Whereas all the lines express phosphatase, 10 of the lines were negative for 5'-N. 5'-N-negative cell lines are found among B as well as T cells, and they do not carry cryptic enzyme activity. In a 5'-N-positive line activity of this enzyme is correlated with growth showing a peak during the logarithmic phase. On the other hand, inhibition of 5'-N does not change the growth curve of this line. Neuraminidase treatment of the cell surface brings about an increase in phosphatase but not in 5'-N activity. 5'-N of two B-cell lines of human peripheral blood lymphocytes shows complete crossreactivity with an antiserum obtained against human placental 5'-N. However, the enzyme of one lymphoma line with B-cell properties (EHR-A-Ramos) does not cross-react with this serum. The results are discussed with respect to suitability of these lymphoblast lines as model systems for the study of immunodeficiencies.
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PMID:Ectoenzymes on the surface of cells from human lymphoblastoid lines: 5'-nucleotidase and phosphatase. 625 29

Using adenosine 5'-monophosphate (Arkesteijn; J. Clin. Chem. Clin. Biochem. 14 (1976) 155) and inosine 5'-monophosphate (Bertrand & Buret; Clin. Chim. Acta 119 (1982) 275) as substrates for the determination of serum 5'-nucleotidase, linear Arrhenius plots were obtained between 25 degrees C and 37 degrees C. With the latter method, in patients with hepatobiliary disease, activation energy is higher than in healthy subjects (67.8 +/- 0.8 kJ.mol-1 vs. 59.2 +/- 1.6 kJ.mol-1, p < 0.001). Neuraminidase treatment resulted in a significant reduction in the activation energy of serum 5'-nucleotidase from patients (63.6 +/- 0.6 kJ.mol-1, p < 0.001). Although the activation energy seen is also influenced by conditions other than sialic acid content, the results obtained are in accordance with the hypothesis that in liver disease serum 5'-nucleotidase becomes more sialylated.
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PMID:Activation energy of serum 5'-nucleotidase as a marker for enzyme heterogeneity. 769 38