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)

1. Adenylate cyclase (EC 4.6.1.1) activity was characterized in human liver, and its subcellular distribution compared with that of three other potential enzyme markers of the pericellular membrane: leucine aminopeptidase (EC 3.4.11.1), gamma-glutamyltransferase (EC 2.3.2.2) and 5'-nucleotidase (EC 3.1.3.5). Although these three enzyme activities were detected in each of the subcellular fractions studied, 85% of the total adenylate cyclase activity was found in the 1000 g pellet ('nuclear' fraction) with a threefold increase in specific activity as compared with the homogenate. No adenylate cyclase activity existed in the 150 000 g supernatant fraction. 2. In the 'nuclear' fraction, adenylate cyclase activity was increased in a dose-dependent fashion by glucagon with a half-maximal stimulation at 10 nmol/l and a maximal four- to seven-fold increase at 1 mumol/l. Catecholamines activated adenylate cyclase 2.5- to three-fold, with an order of potency (protokylol greater than isoprenaline greater than adrenaline greater than noradrenaline) typical of a beta 2-adrenoreceptor. Prostaglandin E1 and NaF also stimulated cyclase two- and four-fold respectively. Insulin, serotonin, dopamine, thyroid-stimulating hormone and ACTH had no effect. Adenosine provoked a weak inhibition at 0.1 mmol/l. Finally guanosine triphosphate and 5'-guanylyl imidodiphosphate induced a marked increase in basal activity, four- and eight-fold respectively, but both reduced the relative increase in enzyme activity due to glucagon or adrenaline. 3. Cyclase from foetal liver (12--16 weeks old) and cirrhotic adult liver appeared to behave similarly to that from normal liver; however, foetal cyclase was more active, and cirrhotic enzyme less active than normal adult liver. Both systems responded to catecholamines via a beta 2-adrenoreceptor. 4. These results validate the use of rat liver adenylate cyclase as a tool for pharmacological and physiological studies.
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PMID:The adenylate cyclase system in human liver: characterization, subcellular distribution and hormonal sensitivity in normal or cirrhotic adult, and in foetal liver. 4 65

Changes in activities of plasma membrane enzymes during liver regeneration may be related to the maintenance of hepatic function or to the regulation of cell proliferation. Plasma membranes were isolated from rat livers at various times after partial hepatectomy, and the specific activities of alkaline phosphatase, (Na+ + K+)-ATPase, leucine aminopeptidase, 5'-nucleotidase, and adenylate cyclase (basal and with glucagon or epinephrine) were measured. Alkaline phosphatase and (Na+ + K+)-ATPase activity increased 3.6-fold and 2-fold respectively, during the first 48 h after partial hepatectomy. The time of onset and duration of change suggest that these increases in activity are involved in the maintenance of bile secretion. Decreases in leucine aminopeptidase activity at 48--108 h and in 5'-nucleotidase activity at 12--24 h were observed, which may be involved in the restoration of protein and accumulation of RNA. The basal activity of adenylate cyclase increased after partial hepatectomy. The response of adenylate cyclase to epinephrine showed a transitory increase between 36 and 108 h after surgery, while the response to glucagon was decreased by approximately 50% at all time points through 324 h after surgery. These changes in the hormone responsiveness of adenylate cyclase are similar to those previously observed in fetal and preneoplastic liver.
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PMID:Changes in plasma membrane enzyme activities during liver regeneration in the rat. 14 24

We have perfused isolated rat livers with hypocalcemic (4.4 mg 100 ml) Krebs-Ringer bicarbonate albumin buffer. After 15 min of perfusion, a substance appeared in the perfusate which decreased rat renal adenylate cyclase activation by parathyroid hormone (PTH). The material in the perfusate was purified greater than 50,000-fold by Bio-Gel P-10 chromatography. The purified antagonist decreased the activation of rat renal cortical adenylate cyclase by PTH, glucagon, and epinephrine 75 to 100%. Concentration response curves for each of the hormones indicated a noncompetitive interaction of the inhibitor with the hormone. The inhibition was not species-specific, as the activation of the parathyroid hormone-responsive adenylate cyclase in cat renal cortex was also abolished by the inhibitor from the perfused rat liver. The inhibitor is a peptide, Mr equal to similar to 1000, which is heat-stable, acid-stable, alkai-labile, and is destroyed by trypsin, leucine aminopeptidase, and elastase. It is not destroyed by phosphodiesterase, 5'-nucleotidase, alkaline phosphatase, neuraminidase, RNase, or phospholipase A. The inhibitor is not produced by isolated rat livers perfused with normocalcemic perfusion media. It is unclear whether the peptide is synthesized by the liver or whether it is a breakdown product of a larger peptide or protein in the liver. This is the first reported peptide inhibitor of adenylate cyclase.
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PMID:Isolation of a unique peptide inhibitor of hormone-responsive adenylate cyclase. 16 24

When liver cells were dispersed with collagenase, their 5'-nucleotidase activity decreased to half the initial level, but it increased to the original level again on culture of the cells for a few days. The activity of another membrane enzyme, alkaline phosphatase, did not decrease on dispersion of the cells, but it increased about 10-fold on culture of the cells. These inductions did not require any hormone, but the effects were greater at a high cell density. These enzymes are located in both the plasma membranes and the cytoplasm, but the enzymes in these two locations can be distinguished by differences in their pH optima, substrate specificities, and susceptibilities to inhibitors. The increases were found to be due to increases in the activity of only the enzymes in the plasma membranes. The increases in enzyme activities were inhibited by actinomycin D, cycloheximide, and puromycin. The activities of leucine aminopeptidase and aminopeptidase B, other membrane enzymes, remained constant during dispersion and culture of the cells. These results show that enzymes in the cell membranes are affected in different ways by cell dispersion with collagenase and subsequent culture of the cells.
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PMID:Biochemical studies on liver functions in primary cultured hepatocytes of adult rats. III. Changes of enzyme activities on cell membranes during culture. 52 39

Stable cultures of mononuclear phagocytes from carrageenan-induced granulomas in mice have been established after enzymatic dispersion of these lesions. The cells can be maintained for up to 3 wk without division in serum-free media. The mononuclear phagocytes were identified by several criteria. The cells are adherent, phagocytic, contain lysosomal acid hydrolases at high specific activities, secrete lysozyme, and bind soluble aggregates of IgG. The activities of 5'-nucleotidase and leucine aminopeptidase in the cultured granuloma cells showed that they resembled macrophages from thioglycollate-stimulated mice but not unstimulated macrophages in these respects. Supernates from the cultured granuloma cells contain factor(s) which induce the proliferation of thymocytes; the release of such factors by the cells is stimulated by lipopolysaccharide.
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PMID:Mononuclear phagocytes from carrageenan-induce granulomas. Isolation, cultivation, and characterization. 67 Aug 87

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.
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PMID:Spontaneous shedding of plasma membrane fragments by human cells in vivo and in vitro. 92 96

Analysis of brush border membrane proteins by gel electrophoresis has revealed a complex polypeptide composition. We have investigated the use of Triton X-114 phase partitioning to fractionate such proteins on the basis of their degree of hydrophobicity. Each of the fractions was composed of a complex but distinct set of proteins. Most proteins were solubilized by Triton X-114 and partitioned into the detergent-poor fraction. Trehalase, gamma-glutamyl transpeptidase, and leucine aminopeptidase were well solubilized (greater than 80%) and enriched 5.1-, 3.9-, and 2.5-fold in the detergent-rich fraction. In contrast, alkaline phosphatase and 5'-nucleotidase were poorly solubilized. The specific activities of these enzymes were increased 2.7- and 2.3-fold in the insoluble protein fraction. Maltase was almost completely solubilized and partitioned into the detergent-poor fraction with a small enrichment factor (1.3). These results suggest that Triton X-114 phase partitioning could be useful as a first step in the purification of many brush border membrane proteins.
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PMID:Fractionation of renal brush border membrane proteins with Triton X-114 phase partitioning. 167 21

Serum alkaline phosphatase (AKP), gamma-glutamyl transpeptidase (gamma-GT), 5'-nucleotidase (5'-NT), leucine aminopeptidase (LAP), AKP gamma-GT isoenzymes, and lipoprotein-X (LP-X) were measured in 97 normal pregnant women and 40 patients with intrahepatic cholestasis of pregnancy (ICP). It was found that in ICP the changing patterns in the four hepatobiliary enzymes were different in different gestational weeks of 3 rd trimester. The changes of gamma-GT and 5'NT were more significant, especially the latter. Six bands were found both in serum AKP and gamma-GT isoenzymes. In ICP the rate of occurrence of AKP1 and AKP2 isoenzymes were elevated. Thus, gamma-GT, 5'-NT, AKP and gamma-GT isoenzymes might be more sensitive parameters for monitoring intrahepatic cholestasis of pregnancy.
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PMID:[Changes in hepatobiliary enzymes and its isoenzymes in intrahepatic cholestasis in pregnancy]. 167 17

1. Liver plasma membranes originating from the sinusoidal, lateral and canalicular surface domains of hepatocytes were covalently labelled with sulpho-N-hydroxysuccinamide-biotin. After solubilization in Triton X-114, treatment with a phosphatidylinositol-specific phospholipase C (PI-PLC), two-phase partitioning and 125I-streptavidin labelling of the proteins resolved by PAGE, six major polypeptides (molecular masses 110, 85, 70, 55, 38 and 35 kDa) were shown to be anchored in bile canalicular membrane vesicles by a glycosyl-phosphatidylinositol (G-PI) 'tail'. 2. Permeabilized 'early' and 'late' endocytic vesicles isolated from liver were also examined. Two polypeptides (110 and 35 kDa) were shown to be anchored by a G-PI tail in 'late' endocytic vesicles. 3. Analysis of marker enzymes in bile-canalicular vesicles treated with PI-PLC showed that 5'-nucleotidase and alkaline phosphatase, but not leucine aminopeptidase and ecto-Ca2(+)-ATPase activities were released from the membrane. A low release and recovery of alkaline phosphodiesterase activity was noted. The cleavage from the membrane of 5'-nucleotidase as a 70 kDa polypeptide was confirmed by Western blotting using an antibody to this enzyme. 4. Antibodies raised to proteins released from bile-canalicular vesicles by PI-PLC treatment, and purified by partitioning in aqueous and Triton X-114 phases, localized to the bile canaliculi in thin liver sections. Antibodies to proteins not hydrolysed by this treatment stained by immunofluorescence the sinusoidal and canalicular surface regions of hepatocytes. 5. Antibodies generated to proteins cleaved by PI-PLC treatment of canalicular vesicles were shown to identify, by Western blotting, a major 110 kDa polypeptide in these vesicles. Two polypeptides (55 and 38 kDa) were detected in MDCK and HepG-2 cultured cells. 6. Since two of the six G-PI-anchored proteins targeted to the bile-canalicular plasma membrane were also detected in 'late' endocytic vesicles, the results suggest that a junction where exocytic and endocytic traffic routes meet occurs in a 'late' endocytic compartment.
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PMID:Priority targeting of glycosyl-phosphatidylinositol-anchored proteins to the bile-canalicular (apical) plasma membrane of hepatocytes. Involvement of 'late' endosomes. 217 97

In 18 horses there was no effect of age or sex on plasma activities of gamma-glutamyl transferase (gamma-GT), 5'-nucleotidase (5'-NT) and leucine aminopeptidase (LAP). All the enzymes were equally stable after storage for one month at -20 degrees C and there was no significant difference between their activities in serum and plasma in clinically normal horses. The pattern of release of gamma-GT, 5'-NT and LAP into plasma was studied in 114 horses which had a variety of orthopaedic, gastrointestinal, cardiovascular and hepatic (necrosis, lipidosis, neoplasia and cirrhosis) conditions. A definitive diagnosis of hepatic disease was established by histological examination of the liver. gamma-GT and 5'-NT were leaked into plasma in hepatic disease and gamma-GT was the more sensitive indicator of liver damage. There was some evidence that gamma-GT and 5'-NT plasma activities may increase in hepatic necrosis as well as in biliary obstruction. LAP was insensitive and not hepatic specific in the horse.
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PMID:Observations on gamma-glutamyl transferase, 5'-nucleotidase and leucine aminopeptidase activities in the plasma of the horse. 256 9


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