Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.31 (beta-glucuronidase)
 7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We found a tumor metastasis-associated heparan sulfate (HS)-degrading endoglycosidase in melanoma cells that is a unique endo-beta-glucuronidase (heparanase) capable of specifically cleaving HS at intrachain sites (M. Nakajima, T. Irimura, N. DiFerrante, and G. L. Nicolson, 1984, J. Biol. Chem. 259, 2283-2290). To perform rapid and microscale quantitative assays of heparanase we developed a solid-phase HS substrate by crosslinking radiolabeled HS onto agarose gel beads using one covalent linkage. The HS from bovine lung was partially N-desulfated and labeled with [14C]acetic anhydride. Free HS amino groups were completely acetylated, and reducing terminal saccharides were reductively aminated. The HS derivatives with amino groups at their reducing termini were coupled to amino-reactive agarose beads. Incubation of the solid-phase HS substrates with B16 melanoma cell extracts in the presence of D-saccharic acid 1,4-lactone (a potent exo-beta-glucuronidase inhibitor) resulted in the time- and dose-dependent release of [14C]HS fragments. Human melanoma cell lines were tested for HS-degrading endoglycosidase using the newly developed solid-phase HS substrates. The human malignant melanoma cells tested had high levels of HS-degrading activity that were comparable to those of highly metastatic murine B16-F10 melanoma cells.
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PMID:A solid-phase substrate of heparanase: its application to assay of human melanoma for heparan sulfate degradative activity. 376 58

Circulating macrophages and metastatic tumor cells can penetrate the vascular endothelium and migrate from the circulatory system to extravascular compartments. Both activated murine macrophages and different metastatic tumor cells (B16-BL6 melanoma; ESb T-lymphoma) attach, invade, and penetrate confluent vascular endothelial cell monlayer in vitro, by degrading heparan sulfate proteoglycans in the subendothelial extracellular matrix. The sensitivity of the enzymes from the various sources degrading the heparan sulfate proteoglycan was challenged and compared by a series of inhibitors. Activated macrophages demonstrate a heparanase with an endoglycosidase activity that cleaves from the [35S]O4 = -labeled heparan sulfate proteoglycans of the extracellular matrix 10 kDa glycosaminoglycan fragments. The macrophages do not store the heparanase intracellularly but it is instead found pericellularly and requires a continuous cell-matrix contact at the optimal pH for maintaining cell growth. The degradation of [35S]O4 = -labeled extracellular matrix proteoglycans by the macrophages' heparanase is significantly inhibited in the presence of heparan sulfate (10 micrograms/ml), arteparon (10 micrograms/ml), and heparin at a concentration of 3 micrograms/ml. In contrast, other glycosaminoglycans such as hyaluronic acid, dermatan sulfate, and chondroitin sulfate as well as the specific inhibitor of exo-beta-glucuronidase D-saccharic acid 1,4-lactone failed to inhibit the degradation of sulfated proteoglycans in the subendothelial extracellular matrix. Degradation of this heparan sulfate proteoglycan is a two-step sequential process involving protease activity followed by heparanase activity. However, the following antiproteases--alpha 2-macroglobulin, antithrombin III, leupeptin, and phenylmethylsulfony fluoride (PMSF)--failed to inhibit this degradation process, and only alpha 1-antitrypsin inhibited the heparanase activity. B16-BL6 metastatic melanoma cell heparanase, which is also a cell-associated enzyme, was inhibited by heparin to the same extent as the macrophage heparanase. On the other hand, heparanase of the highly metastatic variant (ESb) of a methylcholanthrene-induced T lymphoma, which is an extracellular enzyme released by the cells to the incubation medium, was more sensitive to heparin and arteparon than the macrophages' heparanase, inhibited at concentrations of 1 and 3 micrograms/ml, respectively. These results may indicate the potential use of heparin or other glycosaminoglycans as specific and differential inhibitors for the formation in certain cases of blood-borne tumor metastasis.
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PMID:Murine macrophage heparanase: inhibition and comparison with metastatic tumor cells. 380 31

Heparan sulfate (HS), a prominent component of vascular endothelial basal lamina, is cleaved into large Mr fragments and solubilized from subendothelial basal lamina-like matrix by metastatic murine B16 melanoma cells. We have examined the degradation products of HS and other purified glycosaminoglycans produced by B16 cells. Glycosaminoglycans 3H-labeled at their reducing termini or metabolically labeled with [35S]sulfate were incubated with B16 cell extracts in the absence or presence of D-saccharic acid 1,4-lactone, a potent exo-beta-glucuronidase inhibitor, and glycosaminoglycan fragments were analyzed by high speed gel permeation chromatography. HS isolated from bovine lung, Engelbreth-Holm-Swarm sarcoma, and subendothelial matrix were degraded into fragments of characteristic Mr, in contrast to hyaluronic acid, chondroitin 6-sulfate, chondroitin 4-sulfate, dermatan sulfate, keratan sulfate, and heparin which were essentially undegraded. Heparin, but not other glycosaminoglycans, inhibited HS degradation. The time dependence of HS degradation into particular Mr fragments indicated that HS was cleaved at specific intrachain sites. In order to determine specific HS cleavage points, HS prereduced with NaBH4 was incubated with a B16 cell extract and HS fragments were separated. The newly formed reducing termini of HS fragments were then reduced with NaB[3H]4, and the fragments hydrolyzed to monosaccharides by trifluoroacetic acid treatment and nitrous acid deamination. Since 3H-reduced terminal monosaccharides from HS fragments were overwhelmingly (greater than 90%) L-gulonic acid, the HS-degrading enzyme responsible is an endoglucuronidase (heparanase).
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PMID:Metastatic melanoma cell heparanase. Characterization of heparan sulfate degradation fragments produced by B16 melanoma endoglucuronidase. 669 65

Inhibitory activities of A-72363 A-1, A-2 and C, the diastereomers of a neuraminidase inhibitor siastatin B, against various glycosidases were tested in comparison to siastatin B. Despite these compounds differing only in their configuration, each compound showed strikingly different specificities towards the various glycosidases tested. A-72363 C inhibited bovine liver beta-glucuronidase and tumor cell heparanase with IC50 values of 1.6 microM and 12 microM, respectively.
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PMID:A-72363 A-1, A-2, and C, novel heparanase inhibitors from Streptomyces nobilis SANK 60192, II. Biological activities. 860 88

We cloned a gene encoding Scutellaria beta-glucuronidase (sGUS) that is involved in the initiation of H(2)O(2) metabolism in skullcap (Scutellaria baicalensis). This gene consists of a 1581-nucleotide open reading frame, the deduced amino acid sequence of which contains an ATP/GTP binding site and a leucine zipper motif. sGUS has apparent similarity to the heparan sulfate-metabolizing beta-glucuronidase heparanase but no homology to family 2 beta-glucuronidases. In addition, neither the family 2 glycosylhydrolase signature nor family 2 acid-base catalyst was found in this enzyme. These results suggested that sGUS does not belong to the family 2 beta-glucuronidases. We modified several residues predicted to act as the acid-base or nucleophilic residue of sGUS by site-directed mutagenesis. Mutations at Glu(212) or Glu(329) resulted in much lower k(cat)/K(m) values in the mutants as compared with the wild-type enzyme, indicating that these are the acid-base and nucleophilic residues of the active site, respectively. Moreover, similar site-directed mutagenesis confirmed that Tyr(281) is also involved in the beta-glucuronidase activity. The amino acid sequences of small regions containing these active site residues were conserved in heparanases. As sGUS has various structural characteristics in common with heparanase, we concluded that sGUS and heparanase belong to the same new family.
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PMID:Molecular characterization of a novel beta-glucuronidase from Scutellaria baicalensis georgi. 1085 42

A novel class of 2,3-dihydro-1,3-dioxo-1H-isoindole-5-carboxylic acids are described as inhibitors of the endo-beta-glucuronidase heparanase. Several of the compounds, for example, 2-[4-propylamino-5-[5-(4-chloro)phenyl-benzoxazol-2-yl]phenyl]-2,3-dihydro-1,3-dioxo-1H-isoindole-5-carboxylic acid (9c), display potent heparanase inhibitory activity (IC(50) 200-500 nM) and have high selectivity (>100-fold) over human beta-glucuronidase. They also show anti-angiogenic effects. Such compounds should serve as useful biological tools and may provide a basis for the design of novel therapeutic agents.
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PMID:2,3-Dihydro-1,3-dioxo-1H-isoindole-5-carboxylic acid derivatives: a novel class of small molecule heparanase inhibitors. 1514 88

Glycosyl hydrolases hydrolyze the glycosidic bond in carbohydrates or between a carbohydrate and a non-carbohydrate moiety. beta-glucuronidase (GUS) is classified under two glycosyl hydrolase families (2 and 79) and the family-2 beta-glucuronidase is reported in a wide range of organisms, but not in plants. The family-79 endo-beta-glucuronidase (heparanase) is reported in microorganisms, vertebrates and plants. The E. coli family-2 beta-glucuronidase (uidA) had been successfully devised as a reporter gene in plant transformation on the basis that plants do not have homologous GUS activity. On the contrary, histochemical staining with X-Gluc was reported in wild type (non-transgenic) plants. Data shows that, family-2 beta-glucuronidase homologous sequence is not found in plants. Further, beta-glucuronidases of family-2 and 79 lack appreciable sequence similarity. However, the catalytic site residues, glutamic acid and tyrosine of the family-2 beta-glucuronidase are found to be conserved in family-79 beta-glucuronidase of plants. This led to propose that the GUS staining reported in wild type plants is largely because of the broad substrate specificity of family-79 beta-glucuronidase on X-Gluc and not due to the family-2 beta-glucuronidase, as the latter has been found to be missing in plants.
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PMID:Beta-glucuronidase of family-2 glycosyl hydrolase: a missing member in plants. 1925 33