SELECTIVE PLASMINOGEN BINDING - CYSTEINYL-LYSINE-DEXTRAN PROTEIN INTERACTIONS

The dipeptide, L-cysteine-L-lysine, when coupled to a dextran matrix d emonstrates a much higher binding of Glu-plasminogen than dextran alon e. Plasminogen binds to the dipeptide coupled matrix with a high affin ity and binding capacity and is retained by the surface for long perio ds. In comparison, other proteins such as bovine serum albumin, alpha( 2)-antiplasmin, tPA, fibrinogen, and plasmin are not retained by the m aterial demonstrating that the L-cysteine-L-lysine-dextran is highly s elective for Glu-plasminogen. While fibrinogen alone does not bind to the surface, fibrinogen on surfaces to which plasminogen has been pre- adsorbed does demonstrate adsorption interactions. The nature of the i nteractions depend on the amount of plasminogen bound. Fibrinogen in c ontact with high concentrations of adsorbed plasminogen causes an incr ease in the desorption rate of the surface bound protein; if low amoun ts of plasminogen are initially bound, fibrinogen exposure causes an i ncrease in total protein adsorbed by the surface. A higher amount of p rotein adsorbs from a mixed plasma solution. This does not appear to i nhibit the binding of plasminogen, but rather may actually facilitate more plasminogen binding than is the case of plasminogen alone. The di peptide coupled to the dextran matrix appears to be a preferred substr ate for plasminogen binding compared to free lysine and E-amino caproi c acid. (C) 1998 Published by Elsevier Science Ltd. All rights reserve d.