Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.3.5 (5'-nucleotidase)
 3,167 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Reports on correlations between the activity of so-called "marker enzymes of cholestasis" in serum and the ultrastructural changes of the liver are rare. Therefore studies of ultrastructural changes were carried out in 40 patients with intrahepatic cholestasis. In the patients' serum activity of alkaline phosphatase, bile duct alkaline phosphatase, leucine-aminopeptidase (LAP), and 5'-nucleotidase (5'-Nu) as well as the concentration of bilirubin were determined. The results showed a significant correlation between the morphometry of the bile canaliculi and the serum activity of LAP and 5'-Nu. In patients with elevated LAP, an enlargement of the bile canaliculi could be proved. An increased serum activity of 5'-Nu correlated with a higher incidence of bile canaliculi in the ultrastructural picture. The results suggest an investigation of the ultrastructure of bile canaliculi and the determination of marker enzymes of cholestasis in the serum may both contribute to the assessment of cholestatic liver disease.
 ...
PMID:[Ultrastructural-morphometric analysis of liver biopsies in patients with intrahepatic cholestasis. I. Correlations between morphometry of bile canaliculi and so-called "marker enzymes of cholestasis" (author's transl)]. 80 5

Two subfractions of bovine thyroid plasma membranes, light membranes (L-membranes) and heavy membranes (H-membranes), were obtained by a discontinuous sucrose gradient centrifugation of plasma membranes. Electron microscopy of the plasma membrane and its subfractions showed that the H-membranes were very similar to the plasma membrane fraction, both contained junctional complexes, long membrane sheets, and vesicles. In contrast, the L-membranes consisted mainly of short membrane sheets and vesicles, and only a few junctional complexes. The H-membranes had greater adenylate cyclase activity which responded to thyroid-stimulating hormone (TSH) while this hormone had very little effect on the enzyme activity in the L-membranes. Despite the marked difference in TSH stimulation of adenylate cyclase activity in the H- and L-membrane fractions, specific binding of 125I-TSH was similar in both fractions. The L-membranes had higher specific activities of 5'-nucleotidase and Mg2+ATPase while (Na+ + K+)-ATPase and alkaline phosphatase activities were similar in the two subfractions. Protein kinase activity of H-membranes was not significantly stimulated by exogenous cyclic adenosine 3':5'-monophosphate (cAMP). Plasma membranes and H-membranes contained a substrate capable of being phosphorylated. Such phosphorylation was slightly increased by addition of soluble protein kinase. The phosphorylation of exogenous histone by protein kinase of plasma membranes and H-membranes was augmented by cAMP. In contrast, L-membranes had very little protein kinase activity even when exogenous histone was added. They were not a very good substrate for cytosolic protein kinase.
 ...
PMID:Preparation and characterization of subfractions of bovine thyroid plasma membranes. 85 12

In the present attempt, kidney from newly born albino-rat litters has been examined for few enzymes. Those selected for the study include, alkaline phosphatase, acid phosphatase; adenosine monophosphatase, nonspecific osterase and leucine amino peptidase. All the enzymes were observed exhibiting strong positive reactions except moderate acid phosphatase. Furthermore, a comparison of relative enzyme activities with adult rat kidney has been made. Variations in the distribution and intensity of reactions this observed have been discussed in relation to the hypothesis that redistribution of enzymes occurs as the animal becomes older. Functional role of these enzymes in the young kidney have also been discussed.
 ...
PMID:Postnatal enzymorphology of the albino-rat kidney. 86 15

Human erythrocyte ghosts were solubilized in a low ionic strength medium containing 1% Triton X-100 and subjected to electrophoresis in polyacrylamide gels containing Triton X-100. Five major bands were stained with Coomassie Blue, all except one band being heterogenous when re-electrophoresed in gels containing sodium dodecyl sulphate. It was possible to detect acetylcholinesterase, non-specific esterase, ATPase, alkaline phosphatase, 5'-nucleotidase, glyceraldehyde-3-phosphate dehydrogenase, lactate dehydrogenase, and aldolase activities on the Triton-containing polyacrylamide gels. Two of the enzymes, ATPase and 5'-nucleotidase, showed substantial inhibition by Triton X-100 in quantitative studies. This appears to be a useful method for studying membrane enzymes in normal and pathological red cells.
 ...
PMID:Polyacrylamide gel electrophoresis of human erythrocyte membrane enzymes solubilized with triton X-100. 89 Sep 65

Concanavalin A inhibits serum 5'-nucleotidase activity, without causing significant inhibition of alkaline phosphatase activity. This observation serves as the basis for a new method for assaying the 5'-nucleotidase activity in serum, which depends upon the difference between the enzymic hydrolysis of adenosine-5'-monophosphate in the presence and absence of concanavalin A. A denosine released by the 5'-nucleotidase reaction is deaminated by a coupled reaction with adenosine deaminase to liberate inosine and ammonia, and ammonia is measured colorimetrically by the Berthelot reaction. In sera from 40 healthy adult persons, 5'-nucleotidase activity averaged 6.4 U/liter (SD, +/-2.0; range, 3-12). In sera from 100 patients, measurements of 5'-nucleotidase activity by the new assay averaged 8% lower than by a generally accepted method in which phenyl phosphate is used to suppress hydrolysis of adenosine-5'-monophosphate by alkaline phosphatase activity. The clinical validy of the new assay was tested by measuring serum 5'-nucleotidase activities in rats with bile duct ligation and in rats treated with thioacetamide to induce hepatocellular injury.
 ...
PMID:Inhibition by concanavalin A as the basis for a specific assay of serum 5'-nucleotidase activity. 92 81

Human duodenal fluid, secretion fluid of a villous adenoma of the rectum, urine and culture medium of HeLa cells contain plasma membrane fragments which can be revealed by electrophoresis in different media, gel filtration on Sepharose 4-B, electron microscopy and cytochemistry. They carry plasma membrane enzymes (alkaline phosphatase EC 3.1.3.1, leucine aminopeptidase EC 3.4.1.1, 5'-nucleotidase EC 3.1.3.5, maltase EC 3.2.1.20) in the same ratio as the membranes of the cells of origin. Equilibrium density centrifugation results in recovery of these plasma membrane fragments at density 1.190 (g/ml) in CsCl, 1.165 (g/ml) in sucrose, and 1.135 (g/ml) in metrizamide. Similar plasma membrane fragments were decribed previously in the serum of certain liver patients. These observations give evidence that shedding of whole plasma membrane fragments (koinozymic shedding) is a widespread feature of viable cells.
 ...
PMID:Spontaneous shedding of plasma membrane fragments by human cells in vivo and in vitro. 92 96

Sodium butyrate causes HeLa cells to assume an elongated and jagged shape. Ultrastructurally this change is associated with the formation of bundles of microfilaments. Desmosomes were present between adjacent cells. No increase in microtubules was observed in the butyrate-treated cells. Butyrate induces an increase in the activity of 2 membrane-bound enzymes, alkaline phosphatase and 5'-nucleotidase; however, the activity of a third membrane enzyme, acetylcholine esterase, is reduced. The activities of the several other enzymes with different subcellular localizations are not significantly increased. Colcemid and cytochalasin B prevent or reverse the butyrate-mediated change in HeLa cell morphology and also partially inhibit the induction of alkaline phosphatase activity in these cells. The effect of cytochalasin B on alkaline phosphatase induction may be caused by a reduction in protein synthesis produced by this fungal metabolite.
 ...
PMID:Ultrastructural and enzymic modulation of HeLa cells induced by sodium butyrate and the effects of cytochalasin B and colcemid. 97 76

Distribution of the alkaline phosphatase and 5'-nucleotidase activity was studied in blood serum by means of gel filtration through Sephadex G-200 with jaundices of different origin. Both enzymes have two forms differing in the molecular weight, 5'-nucleotidase presenting mainly a high-molecular form in contrast to alkaline phosphatase. This form activity for both enzymes is higher with obturative jaundices as compared to liver cirrhosis and virus hepatitis. The results of incubating sera with desoxicholate and the subsequent gel filtration in its presence, as well as polyacrylamide gel electrophoresis of butanol extracts of the fractions containing high-molecular fragments, evidence for the fact that these fragments are lipoproteid complexes.
 ...
PMID:[Two forms of alkaline phosphatase and 5'-nucleotidase in the serum of persons with jaundice of different origin]. 101 37

The 5'-phosphomonoesterase activity of 5'-nucleotidase (EC 3.1.3.5) and alkaline phosphatase (EC 3.1.3.5) participates in the catabolism of purine ribonucleotides to uric acid in humans. Initial velocity studies of 5'-nucleotidase suggest a sequential mechanism of interaction between AMP nad MgCl2, with a Km of 14 and 3 muM, respectively. With product inhibition studies the apparent Ki's for adenosine, inosine, cytidine, and inorganic phosphate were 0.4, 3.0, 5.0, and 42 mM, respectively. A large number of nucleoside mono-, di-, and tri-phosphate compounds were inhibitors of the enzyme. Allopurinol ribonucleotide, ADP, or ATP were competitive inhititors when AMP was the substrate, with a Ki slope of 120 muM. The phosphomonoesterase activity of human placental microsomal alkaline phosphatase had a pH optimum of 10.0 and had only 18% of maximum activity at pH 7.4. Substrates and inhibitors included almost any phosphorylated compound. The Km for AMP was 0.4 mM and the apparent Ki for Pi was 0.6 mM. Activity was increased only 19% by 5 mM MgCl2. These observations suggest that 5'-nucleotidase and alkaline phosphatase may be inhibited by ATP and Pi, respectively, under normal intracellular conditions, and that AMP may be preferentially hydrolyzed by 5'-nucleotidase.
 ...
PMID:Purine catabolism in man: inhibition of 5'-phosphomonesterase activities from placental microsomes. 101 16

1. Wheat shoot phosphotransferase has been employed, with p-nitrophenylphosphate as a phosphate donor, to specifically phosphorylate the 5'-position of a variety of nucleosides and nucleoside analogues. The specificity of the enzyme towards the 5'-position of pentose nucleosides is testified to by the complete resistance to phosphorylation of 5'-O-methylcytidine. 2. With the use of ion-exchange chromatography, the foregoing procedure has been applied to the large-scale preparation of nucleoside-5'-phosphates with overall yields of the order of 80-90%. Quantitative recovery of unreacted nucleoside makes it possible to use this method without risk of losses either on a small or large scale with rare nucleosides. It is also applicable to acid- and alkali-labile nucleosides which cannot readily be phosphorylated by chemical procedures. 3. The wheat shoot phosphotransferase also phosphorylated a galactopyranosyl nucleoside, as well as such derivatives as 1-(beta-hydroxyethyl)cytosine and 5-(beta-hydroxyethyl)uracil, showing that the enzyme does not have an absolute requirement for a 5-membered sugar ring, but rather for the presence of a primary hydroxyl group. 4. The phosphorylated derivatives of galactopyranosyluracil, and of both hydroxyethyl pyrimidines, were resistant to 5'-nucleotidase. E. coli alkaline phosphatase converted all three nucleotides quantitatively to the starting compounds. 5. A synthesis of 1-(beta-hydroxyethyl)cytosine is described.
 ...
PMID:Preparative enzymic synthesis of nucleoside-5'-phosphates. 109 45


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>