Irvine J, Newlands G F, Huntley J F, Miller H R
Moredun Research Institute, Edinburgh, U.K.
Immunology. 1990 Jan;69(1):139-44.
The interaction of mouse intestinal mast cell proteinase (IMCP) with serine proteinase inhibitors (serpins) in blood was analysed: (i) by examining the capacity of the inhibitors in blood to block the binding of the irreversible serine esterase inhibitor [3H]diisopropyl fluorophosphate (DFP); (ii) by Western blotting. The binding of [3H]DFP to IMCP was blocked very rapidly by inhibitors in mouse serum and, by Western blotting, this inhibition was associated with the appearance of a 73,000 MW proteinase/inhibitor complex together with a series of higher (greater than 100,000) MW complexes. IMCP was not dissociated from these complexes when electrophoresed under reducing conditions, although prior heat treatment of mouse serum (60 for 30-160 min) abolished the formation of all proteinase/inhibitor complexes. Similarly, the activity of a 48,000 MW inhibitor of chymotrypsin was abolished by heat treatment. A titration experiment established that between 0.5 and 5 mg IMCP were inhibited per ml of serum. The properties and MW of the IMCP inhibitor complexes are typical of serpins and suggest that IMCP secreted during intestinal immunological reactions would be rapidly and irreversibly inactivated by plasma-derived inhibitors.
分析了小鼠肠道肥大细胞蛋白酶（IMCP）与血液中丝氨酸蛋白酶抑制剂（丝氨酸蛋白酶抑制剂）的相互作用：（i）通过检测血液中抑制剂阻断不可逆丝氨酸酯酶抑制剂[3H]二异丙基氟磷酸酯（DFP）结合的能力；（ii）通过蛋白质印迹法。小鼠血清中的抑制剂能非常迅速地阻断[3H]DFP与IMCP的结合，并且通过蛋白质印迹法，这种抑制作用与出现一个73,000 MW的蛋白酶/抑制剂复合物以及一系列更高（大于100,000）MW的复合物有关。在还原条件下进行电泳时，IMCP不会从这些复合物中解离出来，尽管事先对小鼠血清进行热处理（60℃处理30 - 160分钟）会消除所有蛋白酶/抑制剂复合物的形成。同样，胰凝乳蛋白酶的48,000 MW抑制剂的活性也会因热处理而丧失。一项滴定实验表明，每毫升血清可抑制0.5至5毫克的IMCP。IMCP抑制剂复合物的性质和分子量是丝氨酸蛋白酶抑制剂的典型特征，这表明在肠道免疫反应期间分泌的IMCP会被血浆来源的抑制剂迅速且不可逆地失活。
