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)

Rat mesenteric artery microsomes were previously reported to degrade 125I-angiotensin II (AII). It is now shown here that washing the membranes with EDTA and including EGTA in the assay media reduces the 125I-AII degradation to very low levels without reducing the specific binding of 125I-AII. Using EDTA wash and including 5 mM MgCl2 and 0.2 mM EGTA the following characteristics of the binding were observed: microscopic association rate constant (k1) = 1.3 to 2.2 X 10(5) M-1 s-1, microscopic dissociation rate constant (k-1) = 3.8 to 6.4 X 10(-4) s-1, equilibrium dissociation constant (Kd) = 1.8 nM and number of binding sites (Bmax) = 193 fmol/mg protein. The subcellular distribution of the specific binding of 125I-AII at 0.16 nM and 1.63 nM was studied along with the distribution of the marker enzymes. The specific binding paralleled the plasma membrane marker (5'-nucleotidase), but not the putative endoplasmic reticulum marker (NADPH-cyt. c-reductase) or the inner mitochondrial marker (cyt. c-oxidase). Thus the binding to the plasma membrane-enriched fraction F2 occurred with a similar affinity (Kd = 2.2 nM) but with higher number of binding sites (420 fmol/mg protein). This study establishes the 125I-AII binding method suitable for determining the changes in the angiotensin receptor characteristics in the pathophysiology of the vascular smooth muscle.
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PMID:Binding and degradation of angiotensin II by mesenteric artery subcellular membranes. 392 92

A light microscopy study on the localization of enzyme activity within atherosclerotic human intracranial arteries was performed on autopsy material obtained within 4 hours of death. The data suggests that the atherosclerotic process first goes through a proliferative phase and then a degenerative phase culminating in the formation of a plaque. In the proliferative phase, smooth muscle cell proliferation has formed a thickened intima. Tetrazolium reductase, adenosine triphosphatase (ATPase) and adenosine monophosphatase (AMPase) activities are present in these cells, while all dehydrogenases and acid phosphatase activities were weak or not present. As the degenerative phase commences, an area of necrosis, lipid and macrophage accumulation is formed on the lumen side of the elastica. This area increases in size until a plaque is formed. Unsaturated polar and nonpolar lipid, cholesterol, alpha-glycerophosphate dehydrogenase, acid phosphatase, and AMPase activities are associated with these areas and in foam cells, which are often found in the thickened intima of the proliferative phase. Tetrazolium reductase and ATPase activities decrease in the thickened intima as the area of necrosis increases in size, while dehydrogenase activity, except that for alpha-glycerophosphate, remains low or not present. Patterns of enzyme alterations for various stages of the disease process in intracranial arteries, the aorta and coronary arteries suggest a similar, if not identical, progression of the atherosclerotic process, irrespective of known differences in the prevalence of atherosclerosis.
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PMID:A histoenzymatic study of human intracranial atherosclerosis. 426 Jul 21

A COMPARATIVE STUDY OF THE ENZYMIC ACTIVITIES OF MEMBRANE FRACTIONS DERIVED FROM GUINEA PIG PANCREATIC HOMOGENATES HAS YIELDED THE FOLLOWING RESULTS: Rough microsomal membranes (derived from the rough ER) have the reductase activities of the two microsomal electron transport systems but lack enzyme activities of Golgi-type (TPPase) and plasmalemmal-type (5'-nucleotidase, beta-leucyl naphthylamidase, Mg-ATPase). Smooth microsomal membranes (derived primarily from the Golgi complex), zymogen granule membranes, and plasmalemmal fractions possess overlapping enzyme activities of plasmalemmal type, in different relative concentrations for each fraction. In addition, the smooth microsomal membranes exhibit TPPase and ADPase activity and share with rough microsomes the reductase activities of the two electron transport chains. Taken together with recent data on the lipid composition of the same fractions (2), these results indicate that the membranes of the pancreatic exocrine cell are chemically and functionally distinct, and hence do not mix with one another during the transport of secretory products.
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PMID:Composition of cellular membranes in the pancreas of the guinea pig. 3. Enzymatic activities. 432 65

Rat astrocytes in primary cultures were employed to isolate the plasma membrane. The method for the isolation of plasma membrane was based on the capacity of the cytoskeleton to adhere to the substratum entrapping intracellular organelles during freezing-thawing cycle performed on the cell. By washing the 'surface adherent framework', the untrapped plasma membrane were recovered and density equilibrium centrifugation resulted in the isolated membrane. The isolated plasma membrane was characterized on the basis of a variety of marker enzymes positive to the plasma membrane such as (Na+ + K+)-ATPase or 5'-nucleotidase as well as the lack of conventional markers of other endomembranes. Ultrastructurally the membranes, as isolated here, were mainly vesicular in nature. The isolated plasma membrane was devoid of the dehydrogenase responsible for NADH-cytochrome c reductase activity. However, NADH-ferricyanide reductase activity and the dehydrogenase system catalyzing the transfer of reducing equivalents from NADH or NADPH to dichloroindophenol seems plasma membrane redox system. The identical specific activity employing dichloroindophenol as an electron acceptor with NADH or NADPH as donor indicate a DT-diaphorase (EC 1.6.99.2) like activity in the astrocytes plasma membrane.
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PMID:Plasma membrane isolated from astrocytes in primary cultures. Its acceptor oxidoreductase properties. 609 77

1. Proteins of fat-globule membrane from bovine milk were solubilized with the non-ionic detergent Triton X-100 in the presence of protease inhibitors. Approximately 25% of the total membrane protein was solubilized and the extracts were shown to contain a sample of most of the major membrane proteins and glycoproteins. 2. The solubilized proteins were separated in flat-beds of Ultrodex by electrofocusing and the pI values for the major proteins, glycoproteins and certain enzymes determined. Several of the proteins displayed marked heterogeneity indicating the existence of protein variants and isoenzymes. Principal pI values for the enzymes assayed were as follows: xanthine oxidase, 7.35--7.55; NADH2: iodonitrotetrazolium reductase, less than 4.5; 5'-nucleotidase, 7.15--7.4; alkaline phosphatase, 5.4--5.7; phosphodiesterase, 4.6--4.8; gamma-glutamyl transpeptidase, 4.4--4.55. 3. Fractions after electrofocusing were analyzed by 'fused rocket' immunoelectrophoresis and crossed immunoelectrophoresis after separation in polyacrylamide gels containing sodium dodecyl sulphate. Major antigens of the membrane include xanthine oxidase and glycoproteins of apparent molecular weights 67 000, 49 500 and 46 000. The latter two components share common antigenic determinants and could not be separated by gel filtration, ion-exchange chromatography, lectin-affinity chromatography or preparative electrofocusing.
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PMID:Separation of the proteins of bovine milk-fat-globule membrane by electrofocusing with retention of enzymatic and immunological activity. 610 13

The plasma membranes of ram spermatozoa were disrupted in a hypotonic EDTA medium and isolated by using a two-phase polymer system of dextran--polyethyleneglycol. The plasma membranes obtained were of a relatively high degree of purity (approximately 70%) as judged by electron microscopy observations and measurements of the marker enzymes alkaline phosphatase, ATPase and AMPase. The activity of succinate cytochrome C reductase, a marker of mitochondrial membranes, was very low.
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PMID:Isolation of plasma membranes from ram spermatozoa by a two-phase polymer system. 616 59

Crude microsomes from porcine endometrium and three subfractions obtained by a modification of Rothschild's technique were characterized by RNA/protein ratio, marker enzyme activities and morphological appearance. The microsomes were devoid of glucose-6-phosphatase activity. They contained approximately 10% of arylesterase-, approximately 30% of both NADPH-cytochrome reductase- and UDPgalactose-N-acetyl-glucosamine beta-D-galactosyltransferase- and approximately 60% of 5'-nucleotidase activities present in the homogenates. Subfraction I (smooth membranes) had twice the galactosyltransferase activity of Subfraction II (smooth and rough membranes + free ribosomes); both subfractions were rich in 5'-nucleotidase and cytochrome reductase activities. Subfraction III (rough membranes) had very low marker activities but exhibited the highest RNA/protein ratio, which was lowest in I.
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PMID:Characterization of microsomal subfractions from porcine endometrium cells. 619 68

The specific activity of HMG-CoA reductase, the major rate-limiting enzyme in the sterol biosynthetic pathway, declined linearly with increasing cell density in four different lines of mammalian cell cultures. As expected, this caused the rates of sterol synthesis from [14C]acetate to decline in a parallel manner. The decrease in reductase activity in the dense cultures was also correlated with decreased incorporation of [14C]acetate into fatty acids and [3H]thymidine into DNA. In contrast, the activities of two enzymes, NADH dehydrogenase and 5'-nucleotidase, which are not involved in lipid synthesis, were independent of changes in cell density. The simplest explanation for these data is tht HMG-CoA reductase and the synthesis of sterol and fatty acids are regulated in concordance with the rate of cell growth and proliferation.
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PMID:The activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase and the rate of sterol synthesis diminish in cultures with high cell density. 626 81

In one experiment Swiss mice were maintained on a 16 or 23% fat diet (laboratory chow with added fat, principally corn oil) or on laboratory chow alone (5.5% fat). In another experiment C57BL/1 mice were given a 23% fat diet (as above) or a low-fat diet (67% laboratory chow, 1.9% corn oil, and 31% starch; 5.5% fat). Colon mucosal samples were analyzed for several enzyme activities. In Swiss mice the analyses revealed the following: 1) Ouabain-insensitive ATPase was unaltered in male mice, but it rose significantly in females fed a high-fat diet (this effect was seen when a resuspended high-speed pellet was analyzed but not seen with the initial homogenate); 2) 5'-nucleotidase activity showed a significant stepwise increase with dietary fat; 3) nonspecific esterase activity tended to rise with a high-fat diet (not significant); 4) beta-glucuronidase levels were not altered by diet fat; and 5) ornithine decarboxylase levels were not altered by diet fat. In C57BL/1 mice analyses were done on ouabain-insensitive ATPase, 5'-nucleotidase, nonspecific esterase, and beta-glucuronidase, but no diet effects were seen. Fecal reductase activity was measured with the use of 2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyltetrazolium chloride hydrate). A high-fat diet did not affect the activity in C57BL/1 mice, but it caused a significant rise in Swiss mice.
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PMID:High-fat diets and fecal level of reductase and colon mucosal level of ornithine decarboxylase, beta-glucuronidase, 5'-nucleotidase, ATPase, and esterase in mice. 632 44

The metabolism of deoxycytidine (dCyd) and dCyd nucleotides in Yoshida ascites sarcoma (YS) cells and the host rat liver was investigated with reference to the increased excretion of urinary dCyd. Incorporation of [14C]orotic acid into the livers of rats at the fifth day after the transplantation of YS cells, the time when the amount of excretion of dCyd in urine was near maximal, was 2 times higher than that into the normal rat livers. After the injection of [14C]orotic acid, the ratio of the specific radioactivity of cytidylate to uridylate moieties of the host liver RNA was measured and found to be higher than that of normal rat liver RNA and to be similar to that of YS cell RNA. When [14C]orotic acid was injected into rats followed by the transplantation of YS cells, the radioactivities present in the livers disappeared more rapidly than those in the control rat livers. The activities of pyrimidine de novo synthesis enzymes, such as cytidine triphosphate synthetase (EC 6.3.4.2) and cytidine diphosphate reductase (EC 1.17.4.1), in YS were higher than those in both rat ascites hepatoma AH 7974 and Walker 256 carcinosarcoma, the transplantations of which did not induce increased excretion of dCyd into urine of the hosts. The activities of dCyd kinase (EC 2.7.1.10) and dCyd deaminase (EC 3.5.4.5) in YS cells were lower than those in the other two tumors investigated. The activities of cytidine triphosphate synthetase and cytidine diphosphate reductase in the livers of YS-bearing rats were elevated compared with those in the livers of rat ascites hepatoma AH 7974- or Walker 256 carcinosarcoma-bearing rats and normal rats, while the activities of dCyd kinase, 5'-nucleotidase (EC 3.1.3.5), and dCyd deaminase were similar between normal rat livers and tumor-bearing rat livers. These results suggest that the increased excretion of urinary dCyd in YS-bearing rats could be caused by both the stimulation of the synthesis of dCyd nucleotides and the low activity of dCyd deaminase in YS cells as well as in the host liver.
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PMID:Origin of increased deoxycytidine excretion into urine of rats bearing Yoshida ascites sarcoma. 672 78


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