[Complex formation of ulinastatin with alpha-thrombin].
The inhibition mode of ulinastatin was indicated noncompetitive by the Lineweaver-Burk's double reciprocal plotting method using the production rate of fibrinopeptide A. Consequently Km of alpha-thrombin could be calculated 2.8 mM and its Vmax was reduced from 24 U/l to 15 U/l by the addition of ulinastatin and Ki of ulinastatin was 1.05 x 10(-2) M. The complex of ulinastatin and alpha-thrombin were found. Furthermore, the mixing of alpha-thrombin, AT-III and ulinastatin produced a larger complex on SDS-PAGE at pH 7.0, and it was evident by the use of Western blotting method, that the complex was consisted of alpha-thrombin, AT-III and ulinastatin. Although ulinastatin and thrombomodulin showed multiple similarities in inhibitory functions on alpha-thrombin, still there are some differences functioning on alpha-thrombin, because of the different binding sites of ulinastatin and thrombomodulin on alpha-thrombin, indicating no crossreaction for antithrombomodulin monoclonal antibody relating to alpha-thrombin binding site of thrombomodulin and it could be contributed to form noncompetitive or uncompetitive inhibitors.
Mimura
K
K
Medical Technology, Toyo Public Health College, Tokyo.
Shinozawa
K
K
Kobayashi
T
T
Fukutake
K
K
Yatsuhashi
T
T
Fukutake
K
K
D001665:Binding Sites; D006023:Glycoproteins / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D011956:Receptors, Cell Surface / Q000378:metabolism; D018179:Receptors, Thrombin; D013917:Thrombin / Q000032:analysis / Q000378:metabolism*; D014361:Trypsin Inhibitors / Q000032:analysis / Q000378:metabolism*
D006023:Glycoproteins; D011956:Receptors, Cell Surface; D018179:Receptors, Thrombin; D014361:Trypsin Inhibitors; D013917:Thrombin; C028665:urinastatin