Some properties of tissue-type plasminogen activator reconstituted onto phospholipid and/or glycolipid vesicles.
Porcine heart tissue-type plasminogen activator (t-PA) was reconstituted onto large multilamellar liposomes with various lipid compositions and the kinetics of plasminogen activation by free or the reconstituted t-PA were studied. Negatively charged lipids, sulfatide and phosphatidylserine (PS), lowered the Km values of t-PA for plasminogen activation (sulfatide, 20-fold; PS, 6-fold), whereas neutral lipid phosphatidylcholine raised the Km. On the other hand, these lipid environments did not affect the amidase parameters and fibrin-binding potency of t-PA. The present results suggest that t-PA could function as a cell-associated form and its plasminogen activation may be regulated by the net charge of the head group of membrane lipids.
D000818:Animals; D002850:Chromatography, Gel; D005337:Fibrin / Q000378:metabolism; D006017:Glycolipids; D007700:Kinetics; D008081:Liposomes; D008970:Molecular Weight; D009206:Myocardium / Q000032:analysis; D010743:Phospholipids; D010958:Plasminogen / Q000378:metabolism; D013552:Swine; D010959:Tissue Plasminogen Activator / Q000378:metabolism*
D006017:Glycolipids; D008081:Liposomes; D010743:Phospholipids; D005337:Fibrin; D010958:Plasminogen; D010959:Tissue Plasminogen Activator