title: Isolation and identification of a 23,000-dalton heparin binding fragment from the amino terminus of bovine thrombospondin.
abstract: Bovine freeze-thaw lysed platelets were fractionated by dextran sulfate affinity chromatography and a purified protein of 23,000 Da was subsequently obtained by G-75 gel filtration of the 0.5 M NaCl fraction. This protein had an amino terminal sequence of Asn-Arg-Ile-Pro-Glu-Ser-Gly-Gly-Asp-Asn-Ser-Val-Phe-Asp-Ile-Phe-Glu-Leu- Thr-Gly-Ala-Ala-Trp-Lys-, a sequence identical to that reported for human thrombospondin. Thrombin-released platelets, fractionated in an identical manner, yielded a protein of 30,000 Da. Immunoblotting of purified bovine platelet thrombospondin and the 150,000- and 30,000-Da plasmin-generated thrombospondin fragments indicated that polyclonal antisera raised against the 23,000-Da protein cross-reacted with intact thrombospondin and the 30,000-Da fragment but not the 150,000-Da fragment. The 23,000-Da protein possessed weak heparin neutralization activity.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001792:Blood Platelets / Q000378:metabolism*; D002417:Cattle; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D006023:Glycoproteins / Q000097:blood*; D006493:Heparin / Q000097:blood*; D007120:Immunochemistry; D008970:Molecular Weight; D010446:Peptide Fragments / Q000097:blood / Q000302:isolation & purification; D011956:Receptors, Cell Surface / Q000302:isolation & purification*; D019699:Thrombospondins
chemical_list: D006023:Glycoproteins; D010446:Peptide Fragments; D011956:Receptors, Cell Surface; D019699:Thrombospondins; C037680:heparin receptor; D006493:Heparin