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)

A sufficient differentiation of lymphatic capillaries from blood capillaries in conventional light microscopy still eludes researches. The endothelium and media of lymphatic capillaries are characterized by a strong 5'-nucleotidase activity, whereas blood capillaries reveal no or significantly lower activity. Alkaline phosphatase activity, on the other hand, missing in the lymphatic capillaries is positive in most of the blood capillaries. For the histochemical visualization of the entire blood capillary bed, dipeptidyl peptidase IV-activity has to be used together with alkaline phosphatase. Various fixation and detection methods of 5'-nucleotidase are compared. In order to demonstrate 5'-nucleotidase activity, a method modified after Heusermann (1979) is considered to be most suitable. The results obtained are discussed with regard to their significance concerning the visualization of lymphatic capillaries. They are compared with a series of investigations in which alkaline phosphatase and dipeptidyl peptidase IV-activity are visualized in blood capillaries additional to the 5'-nucleotidase reaction. Various color reactions reveal a differentiation between blood capillaries and small lymphatics. The isolated visualization of 5'-nucleotidase activity with a simultaneous inhibition of alkaline phosphatase with L-tetramisole is considered to be the best way to histochemically demonstrate lymphatic capillaries. It was shown for the first time that only in the presence of L-tetramisole can small lymphatics be adequately visualized. A satisfactory differentiation between blood and lymphatic capillaries succeeded by means of a different color intensity of the reaction product.
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PMID:Histochemical visualization of lymphatic capillaries in the rat: a comparison of methods demonstrated at the posterior pharyngeal surface. 283 Aug 54

The release of plasma-membrane-bound enzymes by phosphatidylinositol-specific phospholipase C obtained from Bacillus thuringiensis was investigated. Among the ectoenzymes of plasma membrane tested, alkaline phosphodiesterase I was released markedly from rat kidney cortex slices, in addition to alkaline phosphatase and 5'-nucleotidase. Other membrane-bound enzymes; alanine aminopeptidase, leucine aminopeptidase, dipeptidyl peptidase, leucine aminopeptidase, dipeptidyl peptidase IV, esterase and gamma-glutamyl transpeptidase could not be liberated from the treated slices. Alkaline phosphodiesterase I was released linearly from rat kidney slices with the concentration of phosphatidylinositol-specific phospholipase C, but little enzyme was released from rat liver slices. Alkaline phosphodiesterase I separated from kidney tissue with n-butanol still retained phosphatidylinositol and was transformed into a lower molecular weight form by phosphatidylinositol-specific phospholipase C. This suggests an important function for phosphatidylinositol in the binding of alkaline phosphodiesterase I to the plasma membrane of rat kidney cells. The alkaline phosphodiesterase I released from rat kidney had a molecular weight of about 240,000 and an isoelectric point (pI) of 5.4. The enzyme hydrolyzed the phosphodiester linkage of p-nitrophenyl-thymidine 5'-monophosphate at pH 8.9 and had a Km value of 0.3 mM. The enzyme was activated by Mg2+ and Ca2+, but was inhibited by EDTA. Strong inhibition took place on the addition of adenosine 5'-phosphosulfate or the nucleotide pyrophosphates, i.e., UDP-galactose and alpha, beta-methylene ATP.
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PMID:Release of alkaline phosphodiesterase I from rat kidney plasma membrane produced by the phosphatidylinositol-specific phospholipase C of Bacillus thuringiensis. 609 28

Dipeptidylpeptidase IV (EC 3.4.14.5), an enzyme which metabolizes substance P, is present in crude homogenates of hog mesenteric artery and aorta. Its subcellular localization is closely correlated with the plasma membrane marker enzyme 5'-nucleotidase (EC 3.1.3.5) in addition to the kinin and angiotensin metabolizing enzymes angiotensin I converting enzyme (EC 3.4.15.1) and aminopeptidase M (EC 3.4.11.2). The highest level of dipeptidylpeptidase IV is found on the surface membrane-enriched fraction and is immunologically identical to the kidney brush border-bound enzyme. Vascular dipeptidylpeptidase IV sequentially removes the N-terminal Arg1-Pro2 and Lys3-Pro4 dipeptides of substance P and exposes the biologically active C-terminal heptapeptide product to rapid degradation by vascular aminopeptidases.
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PMID:Mesentery vascular metabolism of substance P. 618 94

Plasma membranes (PM) were prepared by discontinuous density gradient centrifugation of crude nuclear fractions from 6 rat livers. These "nuclear" PM (PM-n) were 15-fold enriched in plasma membrane marker enzymes and contained an endopeptidase activity degrading azocasein at pH 7. To get larger amounts of plasma membranes, microsomal fractions obtained in large scale subcellular fractionations were subjected to continuous gradient zonal centrifugation. These "microsomal" PM (PM-m) were 22-fold enriched in 5'-nucleotidase, however, the separation of PM from endocellular membranes was not complete. PM-m showed endopeptidase activity degrading azocasein at pH 5.4 faster than at pH 7.5 and exopeptidases degrading Ala-Pro-pNA and Ala-pNA at pH 7.6. The latter two activities were distributed over the gradient similar to PM marker enzymes and can be solubilized by detergent and proteinase treatment. Therefore, dipeptidyl-aminopeptidase IV and Ala-aminopeptidase are intrinsic plasma membrane enzymes and can be used as additional markers for rat liver plasma membranes. The efficiency and selectivity to solubilize plasma membrane bound endopeptidase, DPP IV and aminopeptidase activities are compared.
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PMID:Proteolytic activities in plasma membrane preparations from rat liver. 1. Preparation of rat liver plasma membranes and solubilization of membrane bound proteases. 636 Jan 63

1. Alkaline phosphodiesterase I release from two tumor cell lines, KB III or AH-130 cells, by the action of phosphatidylinositol-specific phospholipase C (PIPLC) of Bacillus thuringiensis was studied. 2. A significant amount of alkaline phosphodiesterase I was released from both the cell suspension and homogenate of KB III cells, but not from AH-130 cells. 3. The release of the enzyme from KB III cells was dependent on, or proportional to, the reaction time and the PIPLC or cell concentrations. 4. Alkaline phosphatase and 5'-nucleotidase were also released from KB III cells, while gamma-glutamyl transpeptidase and dipeptidyl peptidase IV were not solubilized. The enzyme release by the action of PIPLC was suppressed when purified anti-PIPLC antibody was added to the reaction mixture. This suggests that the enzyme release must be due to the direct action of PIPLC on KB III cells. 5. The alkaline phosphodiesterase I released from KB III cells had a mol. wt of 240,000 and was activated by Mg2+, but strongly inhibited by EDTA and thiol reagents and by 5'-nucleotide-containing compounds. Although KB III cells were derived from Homo sapiens tumor, the released alkaline phosphodiesterase I appeared to be very similar to enzymes obtained from normal tissues of Rattus norvegicus.
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PMID:Alkaline phosphodiesterase I release from eucaryotic plasma membranes by phosphatidylinositol-specific phospholipase C. III. The release from tumor cells. 790 75

1. Ectoenzyme release from kidney brush border membranes of Rattus norvegicus and Sus scrofa domesticus by phosphatidylinositol-specific phospholipase C (PIPLC) of Bacillus thuringiensis was studied. 2. The levels of specific activities of ectoenzymes in R. norvegicus kidney brush border membranes were higher than those in S. scrofa domesticus. About 10-fold higher values were found for specific activities of alkaline phosphatase and gamma-glutamyl transpeptidase in R. norvegicus. 3. Alkaline phosphodiesterase I, alkaline phosphatase and 5'-nucleotidase were released from both R. norvegicus and S. scrofa domesticus brush border membranes, while gamma-glutamyl transpeptidase and dipeptidyl peptidase IV were not solubilized. The enzyme release by the action of PIPLC was suppressed when purified anti-PIPLC antibody was added to the reaction mixture. This suggests that enzyme release must be due to the direct action of PIPLC on kidney brush border membranes. 4. The released alkaline phosphodiesterase I from kidney of S. scrofa domesticus had a molecular weight of 240,000 and was activated by Mg2+ and Ca2+, but strongly inhibited by EDTA.
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PMID:Proof of alkaline phosphodiesterase I as a phosphatidylinositol-anchor enzyme. 839 52

5'-nucleotidase (5'-Nase)-dipeptidyl aminopeptidase IV (DAPase)-alkaline phosphatase (ALPase) triple staining was used to differentiate lymphatics from venous and arterial capillaries in a variety of mammalian tissue sections including human. This triple staining method facilitates specific identification under a light microscope of 5'-Nase activity in lymphatics, DAPase activity in venous capillaries and venules and ALPase activity in arterial capillaries and arterioles. This technique depicts initial lymphatics more clearly and extensively than other methods so far reported although some interspecies and tissue differences are obtained in each enzyme activity.
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PMID:Enzyme triple staining for differentiation of lymphatics from venous and arterial capillaries. 872 74

The Triton-insoluble complex from porcine lung membranes has been separated into two distinct subfractions visible as discrete light-scattering bands following buoyant density-gradient centrifugation in sucrose. Both of these detergent-insoluble complexes were enriched in the glycosyl-phosphatidylinositol (GPI)-anchored ectoenzymes alkaline phosphatase, aminopeptidase P and 5'-nucleotidase, and both complexes excluded the polypeptide-anchored ectoenzymes angiotensin-converting enzyme, dipeptidyl peptidase IV and aminopeptidases A and N. The GPI-anchored proteins in both complexes were susceptible to release by phosphatidylinositol-specific phospholipase C. Both complexes were also enriched in cholesterol and glycosphingolipids, and in caveolin/VIP21, although only the higher-density fraction was enriched in the plasmalemmal caveolar marker proteins Ca(2+)-ATPase and the inositol 1,4,5-trisphosphate receptor. Among the annexin family of proteins, annexins I and IV were absent from the two detergent-insoluble complexes, annexin V was present in both, and annexins II and VI were only enriched in the higher-density fraction. When the mental chelator EGTA was present in the isolation buffers, annexins II and VI dissociated from the higher-density detergent-insoluble complex and only a single light-scattering band was observed on the sucrose gradient, at the same position as for the lower-density complex. In contrast, in the presence of excess calcium only a single detergent-insoluble complex was isolated from the sucrose gradients, at an intermediate density. Thus the detergent-insoluble membrane complex can be subfractionated on the basis of what appears to be calcium-dependent, annexin-mediated, vesicle aggregation into two distinct populations, only one of which is enriched in plasmalemmal caveolar marker proteins.
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PMID:Isolation and characterization of two distinct low-density, Triton-insoluble, complexes from porcine lung membranes. 892 Sep 95

The mechanisms and myocardial alterations associated with NO-deficient hypertension are still far from clear. The aim of the present study was to focus on the enzyme histochemical and subcellular changes in the heart of L-NAME treated rats, as well as to examine the influence of captopril treatment. Wistar rats were administered either L-NAME (40 mg/kg/day) alone or together with captopril (100 mg/kg/day) for a period of 4 weeks. A significant increase of blood pressure confirmed the reliability of the model. The results showed that long-lasting L-NAME administration was accompanied by a decrease of endothelial NO-synthase activity and by a significant local decrease of the following enzyme activities: capillary-related alkaline phosphatase, 5'-nucleotidase and ATPase (but not dipeptidyl peptidase IV) and cardiomyocyte-related glycogen phosphorylase, succinic dehydrogenase, beta-hydroxybutyrate dehydrogenase and ATPases. No activity of these enzymes was found in the scar, whereas a marked increase of alkaline phosphatase and dipeptidyl peptidase IV activities was found in the foci of fibrotization. Histochemical changes correlated with subcellular changes, which were characterized by 1) apparent fibroblast activation associated with interstitial/perivascular fibrosis, 2) heterogeneous population of the normal, hypertrophic and injured cardiomyocytes, 3) enhancement of the atrial granules and their translocation into the sarcolemma, and 4) impairment of capillaries as well as by induction of angiogenesis. Similar alterations were also found in the heart of captopril co-treated rats, despite of the significant suppression of blood pressure. The results indicate that NO-deficient hypertension is accompanied by metabolic disturbances and ultrastructural alterations of the heart and these changes are probably not induced by the renin-angiotension system only.
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PMID:Chronic disturbances in NO production results in histochemical and subcellular alterations of the rat heart. 1080 8

Snake envenomation employs three well integrated strategies: prey immobilization via hypotension, prey immobilization via paralysis, and prey digestion. Purines (adenosine, guanosine and inosine) evidently play a central role in the envenomation strategies of most advanced snakes. Purines constitute the perfect multifunctional toxins, participating simultaneously in all three envenomation strategies. Because they are endogenous regulatory compounds in all vertebrates, it is impossible for any prey organism to develop resistance to them. Purine generation from endogenous precursors in the prey explains the presence of many hitherto unexplained enzyme activities in snake venoms: 5'-nucleotidase, endonucleases (including ribonuclease), phosphodiesterase, ATPase, ADPase, phosphomonoesterase, and NADase. Phospholipases A(2), cytotoxins, myotoxins, and heparinase also participate in purine liberation, in addition to their better known functions. Adenosine contributes to prey immobilization by activation of neuronal adenosine A(1) receptors, suppressing acetylcholine release from motor neurons and excitatory neurotransmitters from central sites. It also exacerbates venom-induced hypotension by activating A(2) receptors in the vasculature. Adenosine and inosine both activate mast cell A(3) receptors, liberating vasoactive substances and increasing vascular permeability. Guanosine probably contributes to hypotension, by augmenting vascular endothelial cGMP levels via an unknown mechanism. Novel functions are suggested for toxins that act upon blood coagulation factors, including nitric oxide production, using the prey's carboxypeptidases. Leucine aminopeptidase may link venom hemorrhagic metalloproteases and endogenous chymotrypsin-like proteases with venom L-amino acid oxidase (LAO), accelerating the latter. The primary function of LAO is probably to promote prey hypotension by activating soluble guanylate cyclase in the presence of superoxide dismutase. LAO's apoptotic activity, too slow to be relevant to prey capture, is undoubtedly secondary and probably serves principally a digestive function. It is concluded that the principal function of L-type Ca(2+) channel antagonists and muscarinic toxins, in Dendroaspis venoms, and acetylcholinesterase in other elapid venoms, is to promote hypotension. Venom dipeptidyl peptidase IV-like enzymes probably also contribute to hypotension by destroying vasoconstrictive peptides such as Peptide YY, neuropeptide Y and substance P. Purines apparently bind to other toxins which then serve as molecular chaperones to deposit the bound purines at specific subsets of purine receptors. The assignment of pharmacological activities such as transient neurotransmitter suppression, histamine release and antinociception, to a variety of proteinaceous toxins, is probably erroneous. Such effects are probably due instead to purines bound to these toxins, and/or to free venom purines.
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PMID:Ophidian envenomation strategies and the role of purines. 1173 31


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