Effect of various polyamino acids and D- and L-amino acids on the blood fibrinolytic system.

1. Comparative additional effects of 24 commercially obtained amino acids and their derivatives were studied by the whole blood clot lysis time (WBCLT) method. D-Arg and L-Lys (greater than 50 micrograms/ml) activated the fibrinolytic system, and poly-L-Glu (mol. wt 6000-90,000) (less than 50 micrograms/ml) were less effective. 2. Poly-L-Arg, poly-L-Lys and poly-(Lys-Ala-Glu-Tyr) accelerated the TPA inhibition in the presence of human plasma. 3. For in vivo experiments, 5 mg of poly-L-Glu were given intravenously to 10 rats. 4. The shortening of WBCLT and elevation of EFA (P less than 0.01) were found after 1 hr administration. 5. The main enzymes which increased in plasma were proved to be the endogenous plasminogen activators with mol. wt higher than 70,000, by zymography.