Yomtova V M, Stambolieva N A, Blagoev B M
Thromb Haemost. 1983 Jun 28;49(3):199-203.
It was found that the effect of heparin on the amidase activity of urokinase (E C 3.4.21.31), plasmin (E C 3.4.21.7) and trypsin (E C 3.4.21.4) depended on the substrate used. No effect of heparin on the amidase activity of urokinase and trypsin was observed when Pyro Glu-Gly-Arg-p-nitroanilide (S-2444) and alpha-N-acetyl-L-lysine-p-nitroanilide (ALNA) were used as substrates. Heparin acted as a uncompetitive inhibitor of trypsin (Ki = 1.2 X 10(-6) M), plasmin (Ki = 4.9 X 10(-6) M) and urokinase (Ki = 1.0 X 10(-7) M) when Bz-Phe-Val-Arg-p-nitroanilide (S-2160), H-D-Val-Leu-Lys-p-nitroanilide (S-2251) and plasminogen, respectively, were used as substrates. These results, as well as the data obtained by studying the effect of the simultaneous presence of heparin and competitive inhibitors suggest that although heparin is not bound at the active center of these enzymes, it may influence the effectivity of catalysis.
结果发现，肝素对尿激酶（EC 3.4.21.31）、纤溶酶（EC 3.4.21.7）和胰蛋白酶（EC 3.4.21.4）酰胺酶活性的影响取决于所使用的底物。当使用焦谷氨酸 - 甘氨酸 - 精氨酸 - 对硝基苯胺（S - 2444）和α - N - 乙酰 - L - 赖氨酸 - 对硝基苯胺（ALNA）作为底物时，未观察到肝素对尿激酶和胰蛋白酶酰胺酶活性的影响。当分别使用苯甲酰 - 苯丙氨酸 - 缬氨酸 - 精氨酸 - 对硝基苯胺（S - 2160）、H - D - 缬氨酸 - 亮氨酸 - 赖氨酸 - 对硝基苯胺（S - 2251）和纤溶酶原作为底物时，肝素对胰蛋白酶（Ki = 1.2×10⁻⁶ M）、纤溶酶（Ki = 4.9×10⁻⁶ M）和尿激酶（Ki = 1.0×10⁻⁷ M）起到非竞争性抑制剂的作用。这些结果，以及通过研究肝素和竞争性抑制剂同时存在时的作用所获得的数据表明，尽管肝素并不结合在这些酶的活性中心，但它可能会影响催化效率。
