Leung K C, Byatt J A, Stephens R W
Thromb Res. 1987 Jun 15;46(6):767-77. doi: 10.1016/0049-3848(87)90069-7.
Two-chain tissue plasminogen activator (t-PA) was found to be inactive in a coupled colorimetric assay for plasminogen activators, but a high level of activity was obtained in the presence of poly-D-lysine. This stimulated activity was strongly inhibited by minactivin, a urokinase inhibitor, but unstimulated enzyme could be shown to be unaffected by minactivin. In the presence of poly-D-lysine minactivin was a very successful competitive inhibitor of t-PA with respect to the substrate, plasminogen. The Ki for minactivin determined by the Henderson method was 2.5 X 10(-12) M, compared to the Km for plasminogen determined as 0.6 X 10(-6) M. The value of Ki for minactivin with u-PA, determined under the same conditions, was 1.6 X 10(-11) M.
在纤溶酶原激活剂的比色偶联测定中，发现双链组织型纤溶酶原激活剂（t-PA）无活性，但在聚-D-赖氨酸存在的情况下可获得高水平的活性。这种刺激活性受到尿激酶抑制剂米那司亭的强烈抑制，但未受刺激的酶不受米那司亭影响。在聚-D-赖氨酸存在的情况下，米那司亭是t-PA针对底物纤溶酶原的非常有效的竞争性抑制剂。通过亨德森方法测定的米那司亭的Ki为2.5×10（-12）M，而测定的纤溶酶原的Km为0.6×10（-6）M。在相同条件下测定的米那司亭对尿激酶型纤溶酶原激活剂（u-PA）的Ki值为1.6×10（-11）M。
