Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:4.2.2.7 (heparinase)
 1,270 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Proteoglycans have been isolated from a high speed supernatant fraction of a mouse mastocytoma by procedures which should minimize alteration of the native protein-polysaccharide molecule. The methods used include in vivo labeling proteoglycans with 35S-sulfate, 3H-leucine and 3H-lysine, centrifugation of the tumor homogenate at 105,000 g, cetylpyridinium fractionation of the supernatant, and further purification of some of the fractions obtained by DEAE-cellulose column chromatography, gel filtration on Sepharose 4B and cellulose acetate electrophoresis. Two major sulfated proteoglycans were obtained, one containing keratan sulfate-like material (KSP-S), the other a heparin-like polymer (HP-S). The presence in HP-S of a compound similar to heparin was confirmed by its digestibility with flavobacterium heparinase. HP-S contained about 4 per cent protein. Glycine was the predominant amino acid, and serine did not appear to be involved in the peptide-carbohydrate linkage. The proteoglycan present in HP-S appeared to be homogeneous when examined using cellulose acetate electrophoresis. KSP-S was found to contain sialic acid and its protein content was significantly higher than that of HP-S. Glutamic and aspartic acids were the most abundant amino acids in KSP-S.
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PMID:Proteoglycans of soluble fraction of mouse mastocytoma. 12 69

The vertebrate body is organized along three geometric axes: anterior-posterior, dorsal-ventral and left-right. Left-right axis formation, displayed in heart and gut development, is the least understood, even though it has been studied for many years. In Xenopus laevis gastrulae, a fibronectin-rich extracellular matrix is deposited on the basal surface of ectoderm cells over which cardiac and visceral primordia move during development. Here I report experiments in which localized perturbation of a small patch of extracellular matrix by microsurgery was correlated with localized randomization of left-right asymmetries. Global perturbation of the extracellular matrix by microinjection of Arg-Gly-Asp peptides or heparinase into the blastocoel resulted in global randomization of left-right asymmetries. From these observations, I suggest that left-right axial information is contained in the extracellular matrix early in development and is independently transmitted to cardiac and visceral primordia.
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PMID:Regulation of vertebrate left-right asymmetries by extracellular matrix. 157 65

The involvement of embryonic cell surface proteoglycans in the attachment and outgrowth of cultured mouse embryos has been investigated. Several lines of evidence indicate that periimplantation stage blastocysts express heparin/heparan sulfate proteoglycans on their cell surfaces that can mediate embryo attachment and trophoblast outgrowth on a variety of matrices. First, in the presence of soluble heparin, the rate at which embryos attach and outgrow on laminin, fibronectin, or monolayers of uterine epithelial cells is reduced considerably. In the case of fibronectin, the rate of outgrowth in the presence of the heparin is slower than in the presence of the Arg-Gly-Asp-Ser-containing peptide that is recognized by a fibronectin receptor. Embryos also attach and exhibit a limited ability to outgrow on platelet factor IV, a heparin binding protein that does not possess the additional binding domains of laminin or fibronectin. Attachment on platelet factor IV is inhibited by heparin. Second, cell surface digestion of attachment-component embryos with heparinase, but not chondroitinase ABC, slows the rate of outgrowth on tissue culture plates in the presence of serum. Third, selective staining for sulfated molecules on the trophectoderm surface of periimplantation stage embryos indicates that such molecules are abundant and uniformly distributed on these cell surfaces. Last, heparin/heparan sulfate proteoglycans are detected as major cell surface components of embryos using vectorial labeling with lactoperoxidase and Na125I. Collectively, these data indicate that heparin/heparan sulfate-bearing molecules have a direct role in attachment and outgrowth of implantation stage blastocysts.
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PMID:Heparin/heparan sulfate is involved in attachment and spreading of mouse embryos in vitro. 295 79

Human angiogenin is an excellent substrate for the adhesion of HT-29 human colon adenocarcinoma cells. These cells adhere more quickly to human angiogenin than to fibronectin, laminin, collagen I, and collagen IV. Anti-angiogenin antibodies and the angiogenesis inhibitors platelet factor-4 and placental ribonuclease inhibitor prevent adhesion of HT-29 cells to angiogenin. Calcium and magnesium ions are not required for adhesion and Arg-Gly-Asp-Ser has no effect, indicating that the interaction is integrin-independent. Instead, adhesion seems to involve a heparan/chondroitin sulfate proteoglycan. Treatment of the cells with heparinase or heparitinase decreases HT-29 cell adhesion onto angiogenin but not onto collagen I. Moreover, cell adhesion is decreased by the presence of heparin or chondroitin sulfates and by preincubation of the cells with inhibitors of proteoglycan synthesis or secretion. In addition, angiogenin binds tightly to heparin-Sepharose, requiring 0.78 M NaCl for elution. Angiogenin-affinity chromatography of a 35S-, 3H-labeled HT-29 cell fraction enriched in cell-surface proteoglycans yields a single, heparinase-sensitive component of apparent molecular mass > 200 kDa, as detected by autoradiography after SDS-polyacrylamide gel electrophoresis. These results suggest that angiogenin could be an effective substrate for tumor cell adhesion during metastasis and may provide a basis for the design of inhibitors of this process.
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PMID:A cell-surface proteoglycan mediates human adenocarcinoma HT-29 cell adhesion to human angiogenin. 751 Jun 98

Previously we isolated a tetrasaccharide-serine and a hexasaccharide-serine from the carbohydrate-protein linkage region of porcine intestinal heparin after digestion with a mixture of Flavobacterium heparinase and heparitinases I and II (Sugahara, K., Yamada, S., Yoshida, K., de Waard, P., and Vliegenthart, J.F.G. (1992) J. Biol. Chem. 267, 1528-1533). In this study four longer carbohydrate sequences (I-IV) attached to Ser or a dipeptide (Ser-Gly or Gly-Ser), which accounted for at least 18.2% of the total linkage region, were isolated from the same heparin preparation after digestion with heparinase only. IV was successfully isolated only after subsequent digestion with glycuronate-2-sulfatase. Their structures were determined by chemical and enzymatic analyses and 1H NMR spectroscopy and found to be the following octa- and decasaccharide sequences attached to Ser in a molar ratio of 1.1:2.3:1.0:1.3: delta HexA(2S)alpha 1-4GlcN(NS,6S)alpha 1-4GlcA beta 1-4GlcNAc alpha 1-4- GlcA beta 1-3Gal beta 1-3Gal beta 1-4Xyl beta 1-O-Ser (I), delta HexA(2S)alpha 1- 4GlcN(NS,6S)alpha 1-4IdoA alpha 1-4GlcNAc alpha 1-4GlcA beta 1- 3Gal beta 1-3Gal beta 1-4Xyl beta 1-O-Ser (II), delta HexA(2S)alpha 1- 4GlcN(NS,6S)alpha 1- 4IdoA alpha 1-4GlcNAc alpha 1-4GlcA beta 1-4GlcNAc-alpha 1- 4GlcA beta 1-3Gal beta 1-3Gal beta 1-4Xyl beta 1-O-Ser (III), delta HexA alpha 1-4GlcN(NS,6S)alpha 1-4IdoA alpha 1-4GlcNAc(6S)alpha 1- 4GlcA beta 1-3Gal beta 1-3Gal beta 1-4Xyl beta 1-O-Ser (IV) (delta HexA, GlcA, IdoA, and GlcN represent 4,5-unsaturated hexuronic acid, D-glucuronic acid, L-iduronic acid, and D-glucosamine, whereas 2S, 6S, and NS stand for 2-sulfate, 6-sulfate, and N-sulfate, respectively). I and II contained 1 mol of Gly in addition to Ser. The four structures indicate that sulfation in heparin chains takes place on the monosaccharide residues located in closer vicinity to the core protein than found for heparan sulfate chains and that there exist at least several heparin subclass chains with different linkage region structures. The significance of the isolated structures is discussed in relation to the biological functions and the biosynthetic mechanisms of heparin.
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PMID:Structure determination of the octa- and decasaccharide sequences isolated from the carbohydrate-protein linkage region of porcine intestinal heparin. 755 27

We have previously demonstrated that chemically modified thrombin preparations induce endothelial cell (EC) adhesion, spreading and cytoskeletal reorganization via an Arg-Gly-Asp (RGD) sequence and the alpha v beta 3 integrin. Native thrombin, however, did not exhibit adhesive properties, consistent with crystal structure analysis, showing that Gly-Asp residues of the RGD epitope are buried within the molecule. We have now identified a possible physiological mean of converting thrombin to an adhesive protein. Plasmin, the major end product of the fibrinolytic system, converted thrombin to an adhesive protein for EC in a time and dose-dependent manner. EC adhesion and spreading was also induced by a low molecular weight (approximately 3,000 D) cleavage fragment generated upon incubation of thrombin with plasmin. Cell adhesion mediated by this fragment was completely inhibited by the synthetic peptide GRGDSP. Conversion of thrombin to an adhesive molecule was significantly enhanced in the presence of heparin or heparan sulfate, while other glycosaminoglycans (GAGs) (e.g., dermatan sulfate, keratan sulfate, chondroitin sulfate) had no effect. The role of cell surface heparan sulfate in thrombin conversion to EC adhesive protein was investigated using CHO cell mutants defective in various aspects of GAG synthesis. Incubation of both thrombin and a suboptimal amount of plasmin on the surface of formaldehyde fixed wild-type CHO-KI cells resulted in an efficient conversion of thrombin to an adhesive molecule, as indicated by subsequent induction of EC attachment. In contrast, there was no effect to incubation of thrombin and plasmin with fixed CHO mutant cells lacking both heparan sulfate and chondroitin sulfate, or with cells expressing no heparan sulfate and a three-fold increase in chondroitin sulfate. A similar gain of adhesive properties was obtained upon incubation of thrombin and plasmin in contact with native, but not heparinase-treated extracellular matrix (ECM) produced by cultured ECs. It appears that cell surface and ECM-associated heparan sulfate modulate thrombin adhesive properties through its heparin binding site in a manner that enables suboptimal amounts of plasmin to expose the RGD domain. Our results demonstrate, for the first time, a significant modulation of thrombin molecule by heparin, resulting in its conversion to a potent adhesive protein for ECs. This conversion is most effective in contact with cell surfaces, basement membranes and ECM.
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PMID:Thrombin adhesive properties: induction by plasmin and heparan sulfate. 824 31

We have previously demonstrated that thrombin possesses an active yet cryptic Arg-Gly-Asp (RGD) site which upon exposure induces endothelial cell (EC) adhesion via alpha nu beta 3 integrin [Bar-Shavit et al. (1991): J Cell Biol 112:335]. This was achieved in the presence of cell surface-associated heparan sulfate proteoglycans (HSPG) and exceedingly low concentrations of plasmin [Bar-Shavit et al. (1993): J Cell Biol 123:1279]. A portion of the cell surface-associated HSPG (glypican) is anchored via a covalently linked glycosyl-phosphatidylinositol (PI) residue, which can be released by treatment with glycosyl-PI-specific phospholipase C (PI-PLC). We report here that exposure of either bovine aortic EC, smooth muscle cells (SMC), or wild-type CHO cells to PI-PLC released HSPG involved in the conversion of thrombin to an adhesive molecule. The adhesion-promoting activity of the released HSPG was abolished following treatment with heparinase but not chondroitinase ABC. Incubation of thrombin with heparan sulfate-deficient CHO cells or cells that were pretreated with PI-PLC failed to induce its conversion to an adhesive molecule, indicating that glypican was playing a major role in this conversion. Moreover, affinity-purified glypican, but not syndecan or fibroglycan, elicited efficient conversion of plasmin-treated thrombin into an adhesive molecule. Antibodies raised against the RGD site in thrombin failed to interact with native thrombin, prothrombin, or the RGD site in other adhesive proteins such as vitronectin, fibrinogen, or fibronectin. Anti-thrombin-RGD antibodies which blocked the adhesion-promoting activity of thrombin were also capable of recognizing thrombin that was first incubated with a suboptimal concentration of plasm in in the presence of PI-PLC-released HSPG. Heparin, heparan sulfate, and PI-PLC-released HSPG had no effect on other cellular properties of thrombin such as receptor binding and growth-promoting activity. Altogether we have demonstrated that the heparin binding domain in thrombin plays a specific role in promoting thrombin adhesive properties and that membrane-associated glypican is likely to be the major physiological inducer of this property.
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PMID:Specific involvement of glypican in thrombin adhesive properties. 917 91

Adenovirus fiber knobs are the capsid components that interact with binding receptors on cells, while an Arg-Gly-Asp (RGD) sequence usually found in the penton base protein is important for the interaction of most adenoviruses with integrin entry receptors. Mouse adenovirus type 1 (MAV-1) lacks an RGD sequence in the virion penton base protein. We tested whether an RGD sequence found in the MAV-1 fiber knob plays a role in infection. Treatment of cells with a competitor RGD peptide or a purified recombinant RGD-containing fiber knob prior to infection resulted in reduced virus yields compared to those of controls, indicating the importance of the RGD sequence for infection. An investigation of the role of integrins as possible receptors showed that MAV-1 yields were reduced in the presence of EDTA, an inhibitor of integrin binding, and in the presence of anti-alpha(v) integrin antibody. Moreover, mouse embryo fibroblasts that were genetically deficient in alpha(v) integrin yielded less virus, supporting the hypothesis that alpha(v) integrin is a likely receptor for MAV-1. We also investigated whether glycosaminoglycans play a role in MAV-1 infection. Preincubation of MAV-1 with heparin, a heparan sulfate glycosaminoglycan analog, resulted in a decrease in MAV-1 virus yields. Reduced MAV-1 infectivity was also found with cells that genetically lack heparan sulfate or cells that were treated with heparinase I. Cumulatively, our data demonstrate that the RGD sequence in the MAV-1 fiber knob plays a role in infection by MAV-1, alpha(v) integrin acts as a receptor for the virus, and cell surface heparin sulfate glycosaminoglycans are important in MAV-1 infection.
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PMID:Usage of integrin and heparan sulfate as receptors for mouse adenovirus type 1. 1917 24