Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.6 (thromboplastin)
 13,278 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The structure of the glycosaminoglycan chain of a heparan sulfate proteoglycan isolated from the conditioned medium of an endothelial cell line has been analyzed by using various degradative enzymes (heparitinase I, heparitinase II, heparinase, glycuronidase, sulfatases) from Flavobacterium heparinum. This proteoglycan inhibits the thromboplastin-activated pathway of coagulation; as a consequence, the catalytic conversion of prothrombin to thrombin is arrested. Heparitinase I (EC 4.2.2.8), an enzyme with specificity restricted to the heparan sulfate portion of the polysaccharide, releases fragments with the electrophoretic mobility and the structure of heparin. Conversely, an assessment of the size and distribution of the heparan sulfate regions has been provided by the use of heparinase (EC 4.2.2.7), which, by degrading the heparin sections of the chain, releases two segments that exhibit the structure of heparan sulfate. One of these segments is attached to the protein core. On the basis of these findings, the heparan sulfate chain can be defined as a copolymer containing heparin regions in its structure. The combined use of these enzymes has made it possible to establish the disaccharide sequence of parts of the glycosaminoglycan moiety of this proteoglycan.
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PMID:Heparin sequences in the heparan sulfate chains of an endothelial cell proteoglycan. 295 57

Proteoglycans were extracted from bovine lung gas exchange tissue, pleura, and bronchioles with 4.0 M guanidinium chloride at 5 degrees C in the presence of protease inhibitors. Preliminary purification of the proteoglycans was achieved by an initial CsCl isopycnic centrifugation (rho 0 = 1.33) and through precipitation with cetylpyridinium chloride in 0.5 M KCl. Further purification and fractionation of proteoglycans was achieved by a second CsCl isopycnic centrifugation (rho 0 = 1.45) in 4.0 M guanidinium chloride. Based on the ultracentrifuge profiles and electrophoretic behavior, the major fractions were pooled. They were purified further by gel filtration on Sepharose CL-2B and characterized by extensive analyses. A heparan sulfate proteoglycan was the major proteoglycan identified in the gas exchange tissue and in the pleura. The major proteoglycan component from the bronchioles was a chondroitin sulfate proteoglycan. Approximate molecular weight of 2 x 10(6) for the heparan sulfate proteoglycan from the pleura and chondroitin sulfate proteoglycan from the bronchioles and 1 x 10(6) for the heparan sulfate proteoglycan from the gas exchange tissue were estimated from gel filtration analyses. After incubation with hyaluronic acid, the chondroitin sulfate proteoglycans from the bronchioles showed an increase in specific viscosity and a higher molecular weight compound eluting near the void volume in Sepharose CL-2B column chromatography. The proteoglycans exhibited varied anticoagulant activities in Stypven, partial thromboplastin and thrombin clotting times and inhibited thrombin-induced platelet aggregation.
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PMID:Isolation and characterization of proteoglycans from bovine lung. 740 Jan 34