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将小麦麦胚和麸皮的浸取液，经加热和用ｐＨ沉淀，获得巯基蛋白酶抑制剂（简称ＣＰＩ）粗品；再经ＤＥＡＥ－Ｓｅｐｈａｒｏｓｅ，ＳｅｐｈａｄｅｘＧ－１００分子筛层析，在ＳＤＳ－ＰＡＧＥ和ＨＰＬＣ柱上得到均为单一蛋白带的小麦ＣＰＩ纯品．其纯化度为原料浸液的４２倍．由ＳＤＳ－ＰＡＧＥ测得ＣＰＩ分子为单一肽链组成，分子量为１３４００ｋｄ，ＳｅｐｈａｄｅｘＧ－１００柱测得ＣＰＩ分子量为１３０００ｋｄ，等电点为ｐＨ５．０，Ｎ末端氨基酸为Ａｌａ．纯化的ＣＰＩ在９０℃下处理４５ｍｉｎ或１００℃下处理１０ｍｉｎ后，仍保持有１００％的抑制活性；在ｐＨ３．０～１１．０的范围内，小麦ＣＰＩ分子非常稳定，抑制活性保持１００％，显示其分子有很高的酸碱耐受性．小麦ＣＰＩ与木瓜蛋白酶的结合是瞬时的．实验表明，该抑制剂对木瓜蛋白酶和无花果蛋白酶有很强的抑制作用，对菠萝蛋白酶有弱抑制作用，但对胰蛋白酶则无抑制作用，表明小麦ＣＰＩ是一种对巯基蛋白酶专一的抑制剂；对木瓜蛋白酶的抑制摩尔比为５．８∶１，属竞争性抑制类型，Ｋｉ值约为２．４４×１０－８ｍｏｌ／Ｌ
The extract of wheat germ and bran was heated and precipitated with pH to obtain the crude product of thiol protease inhibitor (referred to as CPI). The crude product was purified by chromatography on a DEAE-Sepharose, Sephadex G-100, SDS-PAGE and HPLC The pure CPI of wheat is obtained on a single protein band. The degree of purification of the raw material immersion 42 times. The molecular weight of CPI was 13400kd by SDS-PAGE. The molecular weight of CPI was 13000kd on SephadexG-100 column, the isoelectric point was pH5.0, and the N-terminal amino acid was Ala. The purified CPI retained 100% inhibitory activity after being treated at 90 ℃ for 45min or 100 ℃ for 10min. In the range of pH3.0 ~ 11.0, the CPI of wheat was very stable and the inhibitory activity was maintained at 100% Show that its molecules have a high acid-base tolerance. The combination of wheat CPI and papain is transient. Experiments show that the inhibitor has a strong inhibitory effect on papain and fig protease, has a weak inhibitory effect on bromelain, but does not inhibit trypsin, indicating that wheat CPI is a specific inhibitor of sulfhydryl protease ; Inhibition of papain for the molar ratio of 5.8: 1, a competitive inhibition type, Ki value of about 2.44 × 10-8mol / L