Nanninga L B
Thromb Diath Haemorrh. 1975 Apr 30;33(2):244-55.
The levels of fibrinogen and of profibrinolysin (plasminogen) in urokinase-treated plasma as a function of time of incubation were measured. The profibrinolysin concentration was estimated through its complete conversion to fibrinolysin and the inhibition of the enzyme by crystalline soybean trypsin inhibitor. The dissociation constant of the FL-STI complex was determined to be 7 times 10-9 M. The average concentration of profibrinolysin in normal human citrated plasma was found to be 8 times 10-7 M. From the decrease of fibrinogen with time in the urokinase-treated plasma, the free fibrinolysin was calculated. Free fibrinolysin in normal human blood in vivo was estimated from the half-life of fibrinogen and other data obtained in this study to be present at a concentration of 1.7 times 10-10 M. The plasmakinase activity in vivo, expressed as urokinase molarity, is also about 2 times 10-10 M.
测定了经尿激酶处理的血浆中纤维蛋白原和纤溶酶原（血浆酶原）水平随孵育时间的变化。通过将纤溶酶原完全转化为纤溶酶并利用结晶大豆胰蛋白酶抑制剂对该酶的抑制作用来估算纤溶酶原浓度。测定出纤溶酶 - 大豆胰蛋白酶抑制剂复合物的解离常数为7×10⁻⁹ M。发现正常人枸橼酸盐血浆中纤溶酶原的平均浓度为8×10⁻⁷ M。根据经尿激酶处理的血浆中纤维蛋白原随时间的减少情况，计算出游离纤溶酶。根据本研究中获得的纤维蛋白原半衰期及其他数据，估算出正常人血液中体内游离纤溶酶的浓度为1.7×10⁻¹⁰ M。体内血浆激酶活性以尿激酶摩尔浓度表示，约为2×10⁻¹⁰ M。
