Back in 1987, researchers in the Department of Physiology, Miyazaki Medical College, Japan, published a paper in Experientia to show that there was strong fibrinolytic (meaning to break up fibrin, a protein in the blood used in clotting) activity in the vegetable cheese Natto. Natto is a soybean product popular in Japan.
The activity of the enzyme was around 40CU/g wet weight Natto. This enzyme is nattokinase.
The scientists were able to extract the enzyme easily using saline solution.
Sumi H, Hamada H, Tsushima H, Mihara H, Muraki H.
Experientia. 1987 Oct 15;43(10):1110-1.