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)

Transglutaminase activity and subcellular distribution have been examined in both normal and tumour tissue. Subcellular fractionation of rat liver demonstrated a bimodial distribution for transglutaminase between the particulate (approximately 40%) and cytosol (approximately 60%) fractions. Isolation of enriched plasma membrane fractions indicated the presence of membrane associated transglutaminase activity which co-distributed with that of 5'-nucleotidase and Na+/K+-ATPase. Induction of hepatocellular carcinomas in rats by treatment with either diethylnitrosamine or 6-p-dimethylaminophenylazobenzothiazole resulted in a reduction in transglutaminase activity which was accompanied by redistribution of the enzyme to the particulate fraction of the cell. The tumour bearing liver appeared to represent an intermediate stage between the hepatocellular carcinoma and control liver when assayed for content and distribution of transglutaminase activity. The transglutaminase activity of four transplantable rat sarcomas (P7, P8, MC3 and CC5) was found to be greatly reduced when compared with the normal tissues of rat liver, lung and spleen. A further reduction in this activity occurred in the primary growths of the sarcomas P7 and P8 following detection of metastases. Our data suggest that such changes in the distribution and content of transglutaminase may be a feature of tumour tissue and may be of value in both monitoring and investigating the carcinogenic process.
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PMID:Alterations in the distribution and activity of transglutaminase during tumour growth and metastasis. 285 74

Fractionation of rat liver by homogenization and differential centrifugation revealed that only about 83% of the transglutaminase activity in the tissue is in a soluble form, and that the remainder is associated with the particulate fraction. This latter activity remained with the membranes even after they were extensively washed to remove 99% of such soluble enzymes as lactate dehydrogenase and aldolase. Subsequent fractionation of the membranes by isopycnic density gradient centrifugation in sucrose resulted in a single band of transglutaminase activity at a density of 1.194 g/cm3. This activity was coincident with the major band of plasma membranes, which was identified by its content of 5'-nucleotidase, alkaline phosphodiesterase I, alkaline phosphatase and leucine aminopeptidase activities. After treatment with digitonin and fractionation on sucrose gradients, the transglutaminase activity and the plasma membrane marker enzyme activities were found at a new density of 1.210 g/cm3, while the enzyme markers for the other membrane fractions remained unchanged. From these data, we conclude that approximately 17% of the transglutaminase activity in rat liver is specifically associated with the plasma membranes.
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PMID:Subcellular localization of a membrane-associated transglutaminase activity in rat liver. 286 17

When the particulate fraction from a rat liver homogenate was incubated with [3H]putrescine and calcium, the radioactive amine was incorporated into the membranes via a transglutaminase-mediated reaction. Fractionation of the membranes by isopycnic density gradient centrifugation revealed that the radioactive label was coincident with the 5'-nucleotidase and transglutaminase activities which serve as markers for the plasma membrane (Slife, C. W., Dorsett, M. D., Bouquett, G. T., Register, A., Taylor, E., and Conroy, S. Arch. Biochem. Biophys. 241, 329-336). If the labeled membranes were treated with digitonin and fractionated, the radioactivity and the plasma membrane enzyme activities coincidentally shifted to a greater density. Examination of the [3H]putrescine-labeled membranes by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography showed that the largest amount of radioactivity was associated with a large molecular weight material that did not enter the acrylamide gel. Pulse-chase experiments indicated that the large aggregate already was present in the native membrane, or that it was formed very rapidly during the putrescine incubation. The complex did not result from putrescine cross-linking between proteins since dansylcadaverine and [3H]histamine were also selectively incorporated into it. These data show that there are protein substrates in the plasma membrane which are accessible to the membrane-associated transglutaminase and that the substrates form a large molecular weight aggregate which is not dissociated by sodium dodecyl sulfate and disulfide reducing agents.
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PMID:Subcellular location and identification of a large molecular weight substrate for the liver plasma membrane transglutaminase. 286 32

Rat liver plasma membranes contain transglutaminase activity and a large molecular weight protein aggregate that serves as a substrate for this enzyme (Slife, C.W., Dorsett, M.D., Bouquett, G.T., Register, A., Taylor, E., and Conroy, S. (1985) Arch. Biochem. Biophys. 241, 329-336; Slife, C.W., Dorsett, M.D., and Tillotson, M.L. (1986) J. Biol. Chem. 261, 3451-3456). When purified plasma membranes were sonicated and the different plasma membrane domains were separated by sedimentation through a linear sucrose gradient, virtually all of the transglutaminase activity and the large molecular weight transglutaminase substrate were associated with membrane fragments which migrated to a very dense region of the gradient (1.18 g/cm3). The bile canalicular markers, 5'-nucleotidase and HA-4 antigen, were predominantly found at 1.11 g/cm3, while most of the sinusoidal/lateral marker, CE-9 antigen, was detected at 1.14 g/cm3. Smooth membrane vesicles were observed chiefly at the lighter densities upon morphological analysis, while many filament-bearing, plasma membrane segments and junctional complexes were contained in the heavy transglutaminase fractions. These data show that the plasma membrane transglutaminase and the large molecular weight transglutaminase substrate are associated with a distinct region of the plasma membrane.
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PMID:Localization of a liver transglutaminase and a large molecular weight transglutaminase substrate to a distinct plasma membrane domain. 287 87

1. The subcellular distribution of transglutaminase was investigated by using the analytical approach of differential and isopycnic centrifugation as applied to three organs of the rat: liver, kidney and lung. After differential centrifugation by the method of de Duve, Pressman, Gianetto, Wattiaux & Appelmans [(1955) Biochem. J. 63, 604-617], transglutaminase is mostly recovered in the unsedimentable fraction S and the nuclear fraction N. After isopycnic centrifugation of the N fraction in a sucrose density gradient, a high proportion of the enzyme remains at the top of the gradient; a second but minor peak of activity is present in high-density regions, where a small proportion of 5'-nucleotidase, a plasma-membrane marker, is present together with a large proportion of collagen recovered in that fraction. 2. Fractions where a peak of transglutaminase was apparent in the sucrose gradient were examined by electron microscopy. The main components are large membrane sheets with extracellular matrix and free collagen fibers. 3. As these results seem to indicate that some correlation exists between particulate transglutaminase distribution and those of collagen and plasma membranes, the possible binding of transglutaminase by collagen (type I) and by purified rat liver plasma membrane was investigated. 4. The binding studies indicated that collagen is able to bind transglutaminase and to make complexes with plasma-membrane fragments whose density is higher than that of plasma-membrane fragments alone. Transglutaminase cannot be removed from such complexes by 1% Triton X-100, but can be to a relatively large extent by 0.5 M-KCl and by 50% (w/v) glycerol. 5. Such results suggest that the apparent association of transglutaminase with plasma membrane originates from binding in vitro of the cytosolic enzyme to plasma membrane bound to collagen, which takes place during homogenization of the tissue, when the soluble enzyme and extracellular components are brought together.
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PMID:Subcellular localization of transglutaminase. Effect of collagen. 289 39

A cell line (PaTu 8902LM) exhibiting an altered phenotypic appearance was selected from a highly dedifferentiated established human pancreatic tumour cell line (PaTu 8902) by repetitive exposure to laminin-1/nidogen substratum and subsequent selection for adherent cells. Polymerase chain reaction analysis for repetitive DNA indicated that both cell lines are genetically very closely related. The original PaTu 8902 line consisted of flat cells growing in monolayers. In contrast, the obtained PaTu 8902LM cells exhibited a spherical morphology and tended to form clusters. Immunofluorescence analysis using antibodies against apical and basolateral marker enzymes indicated that the PaTu 8902LM cells were polarized, arranging their apical surfaces around central lumenal structures when growing in clusters. In addition, the selected PaTu 8902LM cell line exhibited altered levels of a number of differentiation marker enzymes like 5'-nucleotidase, transglutaminase and plasminogen activators. The different morphological characteristics of both cell lines were maintained even after injection into nude mice. In xenografts, PaTu 8902LM cells were grouped around lumenal, duct-like structures, whereas the original PaTu 8902 cell line formed solid tumours composed of undifferentiated cells. Evidence is presented that the PaTu 8902LM cells are not merely selected from preexisting cells, but that the exposure of PaTu 8902 cells to laminin-1/nidogen had induced a stable transdifferentiation towards the phenotype of the epithelial cells lining the pancreatic secretory ducts. Thus the PaTu 8902LM cells resemble more closely those cells from which tumours of the pancreas originate in vivo and therefore might be a useful cell system in future analyses of the biology of pancreatic tumours which are of increasing incidence and clinical importance.
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PMID:Phenotypical changes of a human pancreatic adenocarcinoma cell line after selection on laminin-1/nidogen (LM/Ng) substratum. 976 55