title: Biochemical and biological properties of a recombinant tissue-type plasminogen activator derived from the rat JMI-229 cell line.
abstract: Recombinant tissue-type plasminogen activator (rt-PA), produced by expression of the genomic t-PA DNA from the JMI-229 cell line, which is of rat origin, in the host cell line, was purified to homogeneity. JMI-229 rt-PA was obtained essentially as a single chain molecule which was quantitatively converted to a two-chain moiety by treatment with plasmin. The plasminogen activating potential of single chain JMI-229 rt-PA was 5-fold lower than that of commercially available human rt-PA (Actilyse) in the absence of fibrin, but comparable in the presence of fibrin; it showed a concentration-dependent binding to fibrin, with a significantly more pronounced binding than Actilyse at low fibrin concentration (85 +/- 8% versus 20 +/- 7% at 0.025 mg/ml fibrin; p = 0.004). In human plasma in the absence of fibrin, the concentrations of both single chain and two-chain JMI-229 rt-PA required to induce 50% fibrinogen degradation in 2 h, were about 15-fold higher than those of Actilyse. Both single chain and two-chain forms of JMI-229 rt-PA and of Actilyse induced a similar time- and concentration-dependent lysis of a 125I-fibrin-labeled plasma clot immersed in human plasma, in the absence of significant systemic fibrinolytic activation. Equally effective concentrations (causing 50% clot lysis in 2 h) were 0.11 or 0.10 micrograms/ml for single chain or two-chain JMI-229 rt-PA, as compared to 0.11 or 0.15 micrograms/ml for single chain or two-chain Actilyse.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Center for Thrombosis and Vascular Research, University of Leuven, Belgium.
authors.forename: H R
authors.initials: HR
authors.lastname: Lijnen
authors.forename: P D
authors.initials: PD
authors.lastname: Webb
authors.forename: B
authors.initials: B
authors.lastname: Van Hoef
authors.forename: F
authors.initials: F
authors.lastname: De Cock
authors.forename: J M
authors.initials: JM
authors.lastname: Stassen
authors.forename: S D
authors.initials: SD
authors.lastname: Prior
authors.forename: D
authors.initials: D
authors.lastname: Collen
mesh_terms: D000577:Amides / Q000378:metabolism; D000818:Animals; D002460:Cell Line; D006224:Cricetinae; D005337:Fibrin / Q000378:metabolism*; D005342:Fibrinolysis / Q000187:drug effects; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D010958:Plasminogen / Q000378:metabolism; D015849:Plasminogen Inactivators / Q000378:metabolism; D011485:Protein Binding; D011655:Pulmonary Embolism / Q000378:metabolism; D051381:Rats; D011994:Recombinant Proteins / Q000737:chemistry / Q000494:pharmacology; D010959:Tissue Plasminogen Activator / Q000737:chemistry* / Q000493:pharmacokinetics / Q000494:pharmacology
chemical_list: D000577:Amides; D015849:Plasminogen Inactivators; D011994:Recombinant Proteins; D005337:Fibrin; D010958:Plasminogen; D010959:Tissue Plasminogen Activator