Title: The activation of type 1 and type 2 plasminogen by type I and type II tissue plasminogen activator
Authors: Mori, K ×
Dwek, R A
Downing, A K
Opdenakker, Ghislain
Rudd, P M #
Issue Date: Feb-1995
Series Title: Journal of Biological Chemistry vol:270 issue:7 pages:3261-7
Abstract: Tissue plasminogen activator (tPA) was fractionated using lysine-Sepharose affinity chromatography. Type I, type II, and a minor peak with high affinity for lysine (designated type D) tPA were recovered. In an indirect amidolytic assay involving native human Glu-plasminogen and fibrin, type II tPA showed a 2-fold higher activity than type I. To explore the combinatorial effect of the variable glycosylation status of both tPA and plasminogen, kinetic constants for fibrin-dependent plasminogen activation were determined for combinations of type I, II, and D tPA with type 1 and 2 plasminogen. Within a 4-fold range, the fastest rate was achieved from the combination of type D (type II + D) tPA and type 2 plasminogen. N-Glycosylation of plasminogen increased the Km value for activation by all tPA variants; N-glycosylation of type I tPA at Asn184 decreased the kcat (turnover) values for the fibrin-dependent activation of plasminogen over type II tPA, while type D tPA showed the highest turnover rate. In the presence of fibrinogen fragments, N-glycosylation of plasminogen at site 289 modulates the kinetics of association of enzyme and substrate, while N-glycosylation at site 184 on tPA modulates the turnover rate of the enzyme.
ISSN: 0021-9258
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Laboratory of Immunobiology (Rega Institute)
× corresponding author
# (joint) last author

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