Barrett J D, Eggena P
Department of Veterans Affairs Medical Center, Sepulveda, CA 91343.
Clin Exp Hypertens. 1993 Sep;15(5):761-80. doi: 10.3109/10641969309041640.
Semipurified soybean trypsin inhibitor added to rat and human plasma leads to a concentration dependent decrease in the rate of angiotensin I generation. This inhibition is due to binding of renin substrate to the inhibitor. Renin substrate present in nephrectomized rat plasma was more susceptible to binding than substrate of the normal rat suggesting structural differences in the substrate generated following nephrectomy. Because trypsin inhibition is necessary for measurement of active and inactive renin, we examined several alternate trypsin inhibitors. The Bowman-Birk inhibitor from soybean had similar actions as purified soybean trypsin inhibitor while trypsin inhibitors from lima bean and chicken did not depress renin substrate, but did have variable effects on the measured levels of active and total plasma renin. Surprisingly, crude soybean trypsin inhibitor did not suppress renin substrate and actually increased angiotensin I generation during PRA and PRC measurements. Since the crude preparation did not suppress renin substrate, changes in the specificity of the inhibitor may occur during its purification. The augmentation of PRA and PRC may be related to angiotensinase inhibitory actions.
向大鼠和人类血浆中添加半纯化大豆胰蛋白酶抑制剂会导致血管紧张素I生成速率呈浓度依赖性下降。这种抑制作用是由于肾素底物与抑制剂结合所致。肾切除大鼠血浆中的肾素底物比正常大鼠的底物更容易与抑制剂结合，这表明肾切除后产生的底物在结构上存在差异。由于测量活性和非活性肾素需要抑制胰蛋白酶，我们研究了几种替代胰蛋白酶抑制剂。来自大豆的鲍曼-伯克抑制剂与纯化的大豆胰蛋白酶抑制剂具有相似的作用，而来自利马豆和鸡的胰蛋白酶抑制剂不会降低肾素底物，但对测得的活性和总血浆肾素水平有不同影响。令人惊讶的是，粗制大豆胰蛋白酶抑制剂在PRA和PRC测量期间并未抑制肾素底物，实际上还增加了血管紧张素I的生成。由于粗制品未抑制肾素底物，抑制剂在纯化过程中可能会发生特异性变化。PRA和PRC的增加可能与血管紧张素酶抑制作用有关。
