Development of renin inhibitor screening system and structure-function relationship of renin inhibitor(s) from food stuffs

利用杆状病毒-昆虫细胞表达系统成功地生产了重组人肾素。以重组人肾素为靶酶，在大豆及分离的大豆肾素抑制剂中发现了肾素抑制活性。分离得到的抑制剂的理化性质与大豆皂甙I相同。此外，我们还研究了不同皂苷对重组人肾素活性的影响，发现在皂苷元的第三位连接葡萄糖醛酸的所谓葡萄糖醛酸苷皂苷是肾素抑制皂苷。此外，我们还发现了水稻中存在一种肾素抑制剂，并鉴定了其结构为油酸和亚油酸。

We succeeded effective production of recombinant human renin by baculovirus-insect cell expression system. Using recombinant human renin as a target enzyme, we found renin inhibitory activity in soybean and isolated soybean renin inhibitor. The physico-chemical data on the isolated inhibitor were identical with those of soyasaponin I. In addition, we studied the effects of various saponins on recombinant human renin activity and found that so-called glucuronide saponin which glucuronic acid connected to the third position of sapogenol was renin inhibitory saponins. Furthermore, we found the existence of the renin inhibitor to rice and identified the structure with oleic acid and linoleic acid.