凝血酶抑制剂抑制动力学研究

Studies on the Inhibition Kinetics of Thrombin Inhibitor

由Ｓ－２５４菌株产生的膜血酶抑制剂是一种多组分的肽类化合物，其中Ｒ－Ｔｈｒ－Ｔｈｒ－ａｒｇｉｎｉｎａｌ组分的活力最强。在３７℃、ｐＨ＝７．４的Ｔｒｉｓ缓冲液中，该抑制剂对凝血酶的抑制作用与抑制刑的浓度关系密切。在抑制剂浓度较小的情况下，抑制剂与酶的结合呈直线关系，随着抑制刑浓度的提高，残留活力曲线则出现漂移。根据Ｄｉｘｏｎ图和Ｌｉｎｅｗｅａｖｅｒ－Ｂｕｒｋ图的研究，该抑制剂对凝血酶的结合与底物呈竞争性抑制，抑制常数Ｋｉ＝２．０×１０－７ｍｏｌ／Ｌ。

The thrombin inhibitor produced by strains S-254 is a peptide of multicomponents.Among them,the component of R-thr-thr-argininal presents the strongest inhibitory activity.The inhibitory activity of the inhibitor to the thrombin is closely related to the concentration of the inhibitor.In case of small inhibitor concentration,there will be a linear relation for the combinatiion of the inhibitor and thrombin.Based on the studies of Dixon plots and Lineweaver-Burk plots,the thrombin inhibitor demonstrates competitive inhibition for thrombin.The inhibitory constant (Ki) is 2.0 ×10-7mol/L.