Strong pro-urokinase activators proved in Japanese soybean cheese Natto

Abstract

In a saline extract of Japanese soybean cheese Natto, the presence of a strong activity of prourokinase activator different from nattokinase was proved. The average activity determined in 6 commercial preparations was 21.8±5.5 CU/g wet weight based on human plasma plasmin. The enzyme fractions separated by gel filtration showed at least three kinds of pro-urokinase activator (PUA) with molecular weights of more than 27 000. As the crude materials, PUAs were stable at neutral pH but were gradually inactivated above 60°C. They were not affected with or without 5 mM Cys, whereas 1 mM DFP and NPGB strongly inhibited all the enzymes, suggesting that PUAs are serine proteases. After a single administration of lyophilized PUA-rich natto with 30 g/body in 5 volunteers, 51-86 years of age, the enhancement of plasma fibrinolysis was maintained for a long time (p< 0.05; values from 4 to 8 hr) with elevation of EFA and increase of FDP levels.