Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.1.53 (sialidase)
 2,694 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The asparagine-linked sugar chains of blood coagulation factor VIII preparations purified from human plasma of blood group A donors and from the culture media of recombinant BHK cells were released as oligosaccharides by hydrazinolysis. These sugar chains were converted to radioactive oligosaccharides by reduction with sodium borotritide and separated into neutral and acidic fractions by paper electrophoresis. Most of the acidic oligosaccharides were converted to neutral ones by sialidase digestion, indicating that they are sialyl derivatives. The neutral and sialidase-treated acidic oligosaccharides were fractionated by serial chromatography on immobilized lectin columns and Bio-Gel P-4 column. Structural study of each oligosaccharide by sequential exo- and endoglycosidase digestion and by methylation analysis revealed that both factor VIII preparations contain mainly high mannose-type and bi-, tri-, and tetra-antennary complex-type sugar chains. Some of the biantennary complex-type sugar chains from human plasma factor VIII contain blood group A and/or H determinant, while those from recombinant product do not. Some of the bi-, tri- and tetra-antennary complex-type sugar chains of the recombinant factor VIII contain the Gal alpha 1----3Gal group. A small number of the triantennary complex-type sugar chains from both preparations was found to contain the Gal beta 1----4(Fuc alpha 1----3)GlcNAc beta 1----4 (Gal beta 1----4GlcNAc beta 1----2)Man group. Studies of pharmacokinetic parameters of the recombinant factor VIII infused into baboons revealed that its half-life in blood circulation is similar to that of plasma derived factor VIII, suggesting that the oligosaccharide structural differences between them do not affect the fate of factor VIII in vivo.
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PMID:Comparative study of the sugar chains of factor VIII purified from human plasma and from the culture media of recombinant baby hamster kidney cells. 156 60

The asparagine-linked sugar chains of blood coagulation factor VIII purified from porcine plasma were released as oligosaccharides by hydrazinolysis. These sugar chains were converted to radioactive oligosaccharides by reduction with sodium borotritide and separated into neutral and acidic fractions by paper electrophoresis. Most of the acidic oligosaccharides were converted to neutral ones by sialidase digestion, indicating that they are sialyl derivatives. The neutral and the sialidase-treated acidic oligosaccharides were fractionated by serial chromatography on immobilized lectin columns. Structural study of each oligosaccharide by sequential exoglycosidase digestion and by methylation analysis revealed that porcine factor VIII contains high mannose-type and bi-, tri-, and tetraantennary complex-type sugar chains. Sixty-seven percent of the complex-type sugar chains contained the Gal alpha 1-->3Gal group, and 23% of the biantennary complex-type sugar chains contained the bisecting N-acetylglucosamine residue. These structures were not detected in the sugar chains of human plasma factor VIII. An in vitro competition study of von Willebrand factor and anti-Gal antibody for binding to factor VIII revealed that von Willebrand factor prevented antibody binding to Gal alpha 1-->3Gal groups in porcine factor VIII sugar chains. This suggests that anti-Gal antibody present in human plasma may not interact with the sugar chains of therapeutic porcine factor VIII. Reverse-transcription polymerase chain reaction was used to identify porcine tissues producing FVIII mRNA. These studies revealed that the kidney is one of the major tissues expressing factor VIII which may contain the sugar chains with the bisecting N-acetylglucosamine residue.
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PMID:Structural study of the sugar chains of porcine factor VIII--tissue- and species-specific glycosylation of factor VIII. 827 17

The human coagulation factor VIII (FVIII) is essential in the intrinsic pathway of blood coagulation and circulates mainly as a non-covalently bound complex with the von Willebrand factor (VWF). This complex (FVIII/VWF) protects FVIII from degradation and cellular uptake, although no biological role has been identified yet for this complex. The FVIII/VWF complex was purified from a healthy donor's plasma by affinity chromatography on a Sepharose 4B-Concanavalin A column and was used to determine its capability to interact with erythrocytes and platelets. The purified FVIII/VWF complex at 6.0 and 12 microg/ml agglutinates rabbit and bovine erythrocytes, and showed negative agglutination with erythrocytes from other species including human ABO. Treatment of erythrocytes with Clostridium perfringens sialidase or trypsin increased four-fold the activity toward rabbit erythrocytes and positive agglutination for human A and B erythrocytes, suggesting the presence of FVIII/VWF-cryptic receptors in these erythrocytes. Goat, pig, or human O erythrocytes were not agglutinated even after enzymatic treatment. Fucose or N-acetyl-glucosamine (GlcNAc), at 10 mM, inhibited agglutinating activity of the complex with rabbit, human A and B erythrocytes, whereas galactose and N-acetyl-galactosamine, even at 200 mM, showed no effect on the complex activity. The FVIII/VWF complex, at 1.5 microg/200,000 platelets, significantly decreased platelet aggregation (p < 0.001) when compared with the effect of platelet-rich plasma; this effect was inhibited with 15 mM GlcNAc or fucose. ELISA assays on FVIII/VWF coated polystyrene plates confirmed specific binding to fucose- or biotinylated GlcNAc-dextran derivatives. We therefore propose that the FVIII/VWF complex possesses lectin activity.
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PMID:Lectin activity of the coagulation factor VIII/von Willebrand complex. 1928 56