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)

Soluble and reconstituted 5'-nucleotidase were used in the binding assays to the laminin/nidogen complex. They both are shown to interact specifically and in a saturable manner with the laminin/nidogen complex using a solid-phase binding assay. Dissociation constants in the region of 10(-8) M were determined for the association of soluble and membrane-bound 5'-nucleotidase. Scatchard analysis of the binding data indicate a stoichiometry of about 2.7 of the homodimeric soluble 5'-nucleotidase to the laminin/nidogen complex. The association of 5'-nucleotidase with laminin/nidogen occurs in the absence of divalent metal ions and does not require N-linked carbohydrate moieties of both laminin/nidogen and 5'-nucleotidase. 5'-Nucleotidase also associates with isolated laminin although with reduced affinity. No binding to isolated nidogen was observed. Peptides containing the RGD sequence did not influence the binding reaction. Monoclonal and polyclonal antibodies directed against 5'-nucleotidase and laminin specifically perturb the association of the reconstituted enzyme to laminin/nidogen. Sulfated polysaccharides such as heparinsulfate and dermatansulfate modulate the interaction of 5'-nucleotidase and laminin/nidogen in a complex biphasic manner and might also regulate the binding reaction in vivo. Immunohistochemistry shows a close spatial correlation of 5'-nucleotidase and laminin also in the epithelium of the small intestine pointing to an in vivo interaction of both glycoproteins.
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PMID:Chicken gizzard 5'-nucleotidase functions as a binding protein for the laminin/nidogen complex. 149 2

Chicken gizzard 5'-nucleotidase represents an ectoenzyme which is linked to the plasma membrane via a phosphatidylinositol glycan. We have characterized the possible domain-like organization of 5'-nucleotidase by limited proteolysis. A hydrophobic proteolytic fragment carrying the intact C-terminus, as well as two major hydrophilic products, were identified. We developed procedures for specific radiolabelling of the active center of 5'-nucleotidase. This allowed us to locate the catalytic site within hydrophilic fragments obtained after limited proteolysis. We demonstrate that removal of N-linked carbohydrate chains increases the sensitivity of 5'-nucleotidase to proteolytic attack, indicating that sugar moieties protect against proteolysis. 5'-Nucleotidase represents a binding protein for components of the extracellular matrix. The interaction between 5'-nucleotidase and the laminin/nidogen complex unmasked proteolytic cleavage sites in the C-terminal portion of the enzyme. This resulted in the specific production of a hydrophilic form of 5'-nucleotidase. In summary, we have further characterized chicken gizzard 5'-nucleotidase: (1) the protein is organized into two domain-like structures, (2) the N-terminal domain harbors the active center; (3) N-linked carbohydrates protect the protein against proteolytic degradation; (4) interaction with components of the extracellular matrix alters the conformation of 5'-nucleotidase.
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PMID:Limited proteolysis of chicken gizzard 5'-nucleotidase. 150 95

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