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: UNIPROT:P00750 (PLA)
16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The stability, activity, and compatibility of alteplase with eight drugs frequently used in cardiovascular disease were studied. Alteplase 1 mg/mL was mixed with each of the following: heparin sodium 80 units/mL in 0.9% sodium chloride injection, dobutamine 10 mg/mL (as the hydrochloride salt) in 0.9% sodium chloride injection or 5% dextrose injection, dopamine hydrochloride 1.6 mg/mL in 0.9% sodium chloride injection or 5% dextrose injection, morphine sulfate 2 mg/mL in 0.9% sodium chloride injection or 5% dextrose injection, lidocaine hydrochloride 8 mg/mL in 0.9% sodium chloride injection or 5% dextrose injection, propranolol hydrochloride 1 mg/mL, metoprolol tartrate 1 mg/mL, or nitroglycerin 0.8 mg/mL in 0.9% sodium chloride injection or 5% dextrose injection. Each mixture was assayed immediately and after storage for 24 hours at 25 degrees C; mixtures containing heparin were also assayed at 4 hours. The alteplase concentration and percentage of the single-chain molecule in each mixture were analyzed by using size-exclusion high-performance liquid chromatography (HPLC). Alteplase bioactivity was determined by a clot-lysis assay. Drug concentrations were assayed by HPLC, pH values of the mixtures were determined, and the mixtures were visually inspected. Instability was defined as a > 10% decrease in concentration; inactivity was defined as a > 10% decrease in activity; incompatibility was defined as detection of a precipitate, opalescence, or color change. Alteplase was not stable in the presence of heparin sodium, morphine sulfate, or dobutamine and was not active in the presence of dopamine hydrochloride. Alteplase was compatible with and stable and active (in vitro) in the presence of lidocaine hydrochloride, propranolol hydrochloride, metoprolol tartrate, or nitroglycerin.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Stability and activity of alteplase with injectable drugs commonly used in cardiac therapy. 852 54

High-performance anion-exchange chromatography (HPAEC) with pulsed-amperometric detection was used to monitor the consistency of the oligosaccharides released from several partially purified preparations of a tissue-type plasminogen activator mutant (TNK-tPA). Differences in the oligosaccharide map were observed, primarily in the neutral carbohydrate region of the separation. Subsequent investigations using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI/TOF/MS) identified the neutral oligosaccharides to be primarily asialo-diantennary complex-type glycans with 2, 1, or 0 galactose residues. Additional asialo-triantennary and asialo-tetrantennary structures were also observed with varying amounts of galactose. Hydrolysis of the chromogenic substrate 4-methyl umbelliferyl-beta-galactoside confirmed that host-cell lysosomal beta-galactosidase is present at the first step in the purification process and is the cause of the observed glycan degradation. Subsequent steps in the purification process quantitatively remove this enzyme. Comparison of HPAEC and MALDI/TOF/MS analysis of time-course samples revealed quite similar rates of degradation and demonstrates the quantitative utility of these methods. HPAEC did not reveal significant changes in the sialylated structures as evidenced by nearly identical profiles for the sialic acid-containing structures.
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PMID:The use of high-performance anion-exchange chromatography and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry to monitor and identify oligosaccharide degradation. 866 Jun 30

Intravenous fat emulsions are frequently given to malnourished patients who are prone to suffer from infectious complications. As injection of low dose endotoxin represents a model to study the human response to acute infection, we sought to determine the effect of lipid emulsion infusion on endotoxin-induced activation of the hemostatic mechanism in man. Ten healthy men received a bolus intravenous injection of endotoxin (lot EC-5; 20 U/kg) midway through a 4-h infusion (125 ml/h) of either dextrose 5% (n = 5) or Intralipid 20% (n = 5). Lipid infusion potentiated endotoxin-induced coagulation activation, as indicated by higher plasma levels of the prothrombin fragment F1 + 2 and of thrombin-antithrombin III complexes (both p < 0.05 for the difference between groups). However, lipid infusion did not influence the fibrinolytic response to intravenous endotoxin, as reflected by similar increases in the levels of tissue-type plasminogen activator and plasmin-alpha 2-antiplasmin complexes in both groups. Endotoxin-induced appearance of plasminogen activator inhibitor type I was enhanced by lipid infusion (p < 0.05). These data suggest that fat emulsion infusion may enhance the tendency towards thrombotic complications in patients with infections.
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PMID:Fat emulsion infusion potentiates coagulation activation during human endotoxemia. 871 84

In search of synthetic high affinity ligands for the mannose receptor, we synthesized a series of lysine-based oligomannosides containing two (M2L) to six (M6L5) terminal alpha-D-mannose groups that are connected with the backbone by flexible elongated spacers (16 A). The synthesized cluster mannosides were all able to displace binding of biotinylated ribonuclease B and tissue-type plasminogen activator to isolated human mannose receptor. The affinity of these cluster mannosides for the mannose receptor was continuously enhanced from 18-23 microM to 0.5-2.6 nM, with mannose valencies increasing from two to six. On average, expansion of the cluster mannoside with an additional alpha-D-mannose group resulted in a 10-fold increase in its affinity for the mannose receptor. M3L2 to M6L5 displayed negative cooperative inhibition of ligand binding to the mannose receptor, suggesting that binding of these mannosides involves multiple binding sites. The nanomolar affinity of the most potent ligand, the hexamannoside M6L5 makes it the most potent synthetic cluster mannoside for the mannose receptor yet developed. As a result of its high affinity and accessible synthesis, M6L5 not only is a powerful tool to study the mechanism of ligand binding by the mannose receptor, but it is also a promising targeting device to accomplish cell-specific delivery of genes and drugs to liver endothelial cells or macrophages in bone marrow, lungs, spleen, and atherosclerotic plaques.
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PMID:Lysine-based cluster mannosides that inhibit ligand binding to the human mannose receptor at nanomolar concentration. 891 Apr 12

We report on the effect of prolonged hyperglycaemic (11 and 30 mM D-glucose) culture conditions on human mesangial cell matrix metalloproteinases (MMPs), plasminogen activators and their inhibitors. The results indicate that hyperglycaemic conditions modulate the potential proteolytic activity of the enzymes secreted by confluent cultures of these cells. Gelatinase A (MMP-2) activity was always higher in cultures maintained under hyperglycaemic than under normoglycaemic conditions (4 mM D-glucose). In contrast, gelatinase B (MMP-9) activity was decreased under the same conditions. Matrilysin (MMP-7) activity was decreased by up to 100% under hyperglycaemic conditions. Reverse transcriptase-PCR and Western-blotting analyses indicate that in all cases both the transcripts and the protein level were correlated with enzymic activity. One tissue inhibitor of metalloproteinases, TIMP-2, was barely detectable under hyperglycaemic conditions (30 mM D-glucose). In contrast, TIMP-1 increased during the initial 2 weeks of culture in hyperglycaemic conditions and remained elevated to the end of the experiment (4 weeks). Under normoglycaemic conditions TIMP-1 decreased after 2 weeks of culture. Hyperglycaemic conditions also decreased markedly the activity of tissue plasminogen activator (t-PA). This seemed to be due to increased synthesis of its inhibitor, plasminogen activator inhibitor 1, under these conditions rather than to decreased expression of the t-PA enzyme.
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PMID:Modulation of neutral protease expression in human mesangial cells by hyperglycaemic culture. 900 62

The recombinant plasminogen activator (rDSPA alpha 1) from the vampire bat Desmodus rotundus is a promising new thrombolytic agent that exhibits a superior pharmacological profile if compared to tissue-type plasminogen activator (t-PA) or streptokinase. In the present study the structures of the carbohydrate moieties at the two N-glycosylation sites (Asn-117, Asn-362) of rDSPA alpha 1 expressed in Chinese hamster ovary cells were determined. N-Linked glycans were enzymatically released from isolated tryptic glycopeptides by peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase F digestion and separated by two-dimensional HPLC. Oligosaccharide structures were characterized by analysis of carbohydrate composition and linkage, by mass spectrometry, and by sequence analysis in which the fluorescently labeled glycans were cleaved with an array of specific exoglycosidases. More than 30 different oligosaccharides were identified. The results revealed that Asn-117 carried a mixture of one high-mannose structure (17% of site-specific glycosylation), three hybrid glycans (26%) and predominantly biantennary complex N-glycans (54%). Glycosylation site Asn-362 was found to comprise complex glycans with biantennary (50%), 2,4- and 2,6-branched triantennary (21%, 11%), and tetraantennary structures (10%), which were fucosylated at the innermost residue of N-acetylglucosamine. Mainly neutral and monosialylated glycans, and smaller quantities of disialylated glycans, were detected at both glycosylation sites. Sialic acid was alpha 2-3 linked to galactose exclusively. As shown in this study the N-glycans attached to Asn-117 of rDSPA alpha 1 are more processed during biosynthesis than the high-mannose structures linked to Asn-117 of t-PA, to which the polypeptide backbone of rDSPA alpha 1 is structurally closely related.
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PMID:Analysis of site-specific N-glycosylation of recombinant Desmodus rotundus salivary plasminogen activator rDSPA alpha 1 expressed in Chinese hamster ovary cells. 906 66

The oligosaccharide structures present on Asn5 of the Pichia pastoris-expressed recombinant kringle 2 domain of tissue-type plasminogen activator [(r)-[K2tPA]] have been determined by a combination of techniques, including HPLC, FPLC, gel filtration, endoglycosidase digestions and mass spectrometry. The major oligosaccharides identified after their liberation by either hydrazinolysis or by the enzyme peptide:N4-(N-acetyl-beta-glucosaminyl)asparaginyl amidase, were in the oligomer range of (mannose)8(N-acetylglucosamine)2 (Man8GN2) to Man18GN2. The preponderance of these glycans spanned Man9GN2 to Man12GN2, and the major overall product was Man10GN2. An additional (less than 5%) amount of the polypeptide was hyperglycosylated. In contrast with glycoproteins produced in Saccharomyces cerevisiae, our results with specific mannosidase digestions were consistent with previous studies showing that (alpha 1,3)-linked mannose residues were not present in extensions of the core Man8GN2 unit. The results show that the N-linked glycosylation pathways in P. pastoris are substantially different from those found in S. cerevisiae, with shorter Man(alpha 1,6) extensions to the core Man8GN2 and the apparent lack of significant Man(alpha 1,3) additions representing the major processing modality of N-linked glycans in P. pastoris.
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PMID:Glycosylation properties of the Pichia pastoris-expressed recombinant kringle 2 domain of tissue-type plasminogen activator. 912 88

To study the role of the mannose receptor in cellular uptake and degradation of tissue-type plasminogen activator (t-PA), a set of five monoclonal antibodies (Moab) was generated against the mannose receptor isolated from human placental tissue. All Moab specifically recognised the 175 kDa mannose receptor in a crude placenta extract, as shown in Western blot analysis. By use of immunohistochemistry, we showed that in human placenta only the Hofbauer cells (fetal macrophages) express the mannose receptor. Epitope competition experiments indicated that the Moab bound to at least two different epitopes on the receptor molecule. Moab 14-3, 14-5, and 15-2, which are directed against one of these epitopes, strongly inhibited the interaction between the purified mannose receptor and t-PA. These Moab also inhibited mannose receptor-mediated degradation of t-PA by cultured human macrophages. The low density lipoprotein receptor-related protein (LRP) mediated t-PA degradation was not affected by the Moab. It is concluded that the Moab are useful for studying the expression of the human mannose receptor in Western blot and in immunohistochemistry, and for studying the interactions between the human mannose receptor and the mannose-containing ligand t-PA.
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PMID:Monoclonal antibodies against the human mannose receptor that inhibit the binding of tissue-type plasminogen activator. 913 49

The N-linked glycans assembled in Pichia pastoris on the recombinant kringle 2 domain of human tissue-type plasminogen activator (r-[K2tPA]) are composed of approx. 80% neutral and 20% charged species. After peptide:N4-(N-acetyl-beta-glucosaminyl)asparaginyl amidase-catalysed liberation of the oligosaccharides from the purified glycopeptide, the glycan mixture was resolved by HPLC on amino-silica-based resin. Oligosaccharide mapping of the resulting mixture by HPLC, gel filtration and time-of-flight matrix-assisted laser-desorption-ionization-with-delayed-extraction mass spectrometry (TOF-MALDI DE-MS) revealed that > 90% of the charged species consisted of a series of oligosaccharides possessing molecular masses that were consistent with a range of saccharides comprising phospho-Man10GlcNAc2-phospho-Man14GlcNAc2, with phospho-Man11GlcNAc2 representing the major species. The remaining material in the charged fraction contained identifiable phosphorylated glycans that were one or two mannose units shorter, and one to four mannose units longer, than those present in the above range of oligosaccharides. Treatment of the native charged glycan pool with alkaline phosphatase did not result in molecular-size alterations, showing that phosphomonoesters are not present. Mild acid hydrolysis of the glycans led to a decrease in the size of all charged glycans by one mannose residue, providing phospho-Man9GlcNAc2-phospho-Man13GlcNAc2. Following this procedure, treatment with alkaline phosphatase resulted in size decreases that were equivalent to the loss of one phosphate group from each glycan. This demonstrates that all charged glycans isolated contained phosphate in phosphodiester bonds to two mannose units. The present study shows that P. pastoris cells possess the capability of assembling phosphorylated glycans having the phosphate moiety present in phosphodiester linkages with two mannose units. These saccharides, like the neutral oligosaccharides, contain considerably smaller amounts of mannose than glycans present in other strains of yeast.
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PMID:Characterization of the acidic oligosaccharides assembled on the Pichia pastoris-expressed recombinant kringle 2 domain of human tissue-type plasminogen activator. 935 3

Recently, we developed a series of cluster mannosides that were able to inhibit tissue-type plasminogen activator (t-PA) binding to the isolated mannose receptor. The mannoside with the highest affinity was able to inhibit t-PA clearance by the liver in the rat. To test whether these mannosides would also be efficient inhibitors in humans, we studied the expression of the mannose receptor in the human liver and determined the efficacy of the mannosides to inhibit mannose receptor-mediated t-PA degradation by both rat and human cells. Immunohistochemistry indicates that, like the rat, human liver endothelial cells and human Kupffer cells do express the mannose receptor. The mannosides do inhibit mannose receptor-mediated t-PA binding, association, and degradation by isolated rat liver endothelial cells and t-PA association and degradation by cultured human macrophages at similar concentrations. The cluster mannoside with six mannose residues connected with a backbone of five lysine groups (M6L5) was, like unlabeled t-PA, able to inhibit 125I-t-PA degradation in the nmol/L range, while the mannoside M5L4 inhibited 125I-t-PA degradation in the micromol/L range. The concentrations of mannoside necessary to inhibit 125I-t-PA degradation in vitro were comparable with the concentrations necessary to inhibit mannose receptor-mediated 125I-t-PA clearance in vivo. We conclude that there is no species difference between rat and humans with respect to the distribution of the mannose receptor in the liver and the affinity of the cluster mannosides, establishing the relevance of the inhibition of mannose receptor-mediated t-PA clearance by M6L5 as observed in the rat, for the human situation.
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PMID:Cluster mannosides can inhibit mannose receptor-mediated tissue-type plasminogen activator degradation by both rat and human cells. 936 76


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