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Selective Capture (Molecular Recognition) of Acidic Steroids by Dietary Resistant Protein and Modeling of Antitumor Foods

通过膳食抗性蛋白选择性捕获（分子识别）酸性类固醇和抗肿瘤食品建模

基本信息

批准号：
13660132
负责人：
IWAMI Kimikazu
金额：
$ 2.3万
依托单位：
Kyoto Prefectural University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

项目摘要

An insoluble "high-molecular-weight fraction" centrifugally separable from Protin^R-digested soy protein isolate has been referred to as HMF, which has a high capacity to capture bile acids and to accerelate their fecal excretion. A significant correlation was observed for the fecal excretion of nitrogen, lipid and acidic or neutral steroid in HMF-fed rats. Therefor, the feces from HMF-fed rats were rinsed out in pH 7.4 phosphate buffer, 70% ethanol and 1% Triton-containing 8M urea, and the resulting insoluble residue was examined for its amino acid composition and bile acid-caturing capacity. The constituent amino acids were Leu > Ala > Val, Ile > Gly > Phe > Pro > Tyr > Ser > Glu etc. in order of molar ratio, being quite similar in pattern to those of the remnant after artificial digestion with mammalian digestive enzymes. The bile acid-capturing capacity turned out to be 14 μmol/g feces which was nearly compatible with the amount of bile acids extractable from powdered whole feces w … More ith 70% ethanol after washing with the phosphate buffer. Accordingly the HMF remnant as well as the insoluble feces should be called "soybean resistant protein" with due consideration for no more digestible characteristic. A comparison of bile acid-capturing capacity was made by equilibrium dialysis on litocholic acid (LCA), deoxycholic acid (DCA), chenodeoxycholic acid (CDCA), hyodeoxycholic acid (HDCA), taurodeoxycholic acid (TDCA), glycocheno-deoxycholic acid (GCDCA), ursodeoxycholic acid (UDCA) and cholic acid (CA). Consequently, soybean resistant protein had a high affinity for bile acids in order of LCA, DCA, CDCA >> HDCA > TDCA, GCDCA > UDCA, CA. Noteworthily there was a clear difference between DCA and CA in that respect. This difference was also ascertained from a pattern of uncompetitive inhibition by DCA in Eadie-Scatchard plot of bound CDCA against its corresponding bound/free ratio with the aid of ^<14>C-CDCA. When its bile acid-capturing capacity was compared with those of various resistant proteins prepared by artificial digestion from leguminous and cereal food proteins, any preparation was far inferior to soybean resistant protein in affinity for secondary bile acid. The majority of primary bile acids escaped from intestinal absorption undergo dehydroxylation by enteric bacteria and convert to secondary bile acids fairly risky as promorter for carcinogenesis. Taking into account such a high affinity of resistant proteins for secondary bile acids, their successive intake in ordinary eating habits contributes greatly to cancer prevention besides inprovement in lipidemia or cholesterolemia. Less

从蛋白质R消化的大豆分离蛋白中分离出的一种不溶的“高分子量组分”被称为HMF，它具有很高的捕获胆汁酸和加速其排泄量的能力。饲喂HMF的大鼠的粪便氮、脂和酸性或中性类固醇排泄量之间存在显著的相关性。为此，饲喂HMF的大鼠的粪便在pH 7.4的磷酸盐缓冲液、70%乙醇和1%含Triton的8M尿素中漂洗，并检测其氨基酸组成和胆汁酸摄取能力。组成氨基酸按摩尔比依次为Leu&GT、Ala&Gt、Val、Ile&Gt、Gly&Gt、Phe&Gt、Pro&Gt、Tyr&Gt、Ser&Gt、Glu等，与哺乳动物消化酶人工消化后的残留物在形态上十分相似。对胆汁酸的捕集能力为14μ摩尔/克粪便，与…从粉状全粪便中提取胆汁酸的量基本一致。用磷酸盐缓冲液洗涤后，超过70%的乙醇。因此，HMF残留物以及不溶性粪便应被称为“大豆抗性蛋白”，但不应考虑更易消化的特性。比较平衡透析法对胆汁酸(LCA)、脱氧胆酸(DCA)、鹅去氧胆酸(CDCA)、猪去氧胆酸(HDCA)、牛磺酸脱氧胆酸(TDCA)、甘氨酸脱氧胆酸(GCDCA)、熊去氧胆酸(UDCA)和胆酸(CA)的捕集能力。因此，大豆抗性蛋白对胆汁酸的亲和力大小顺序为：LCA、DCA、CDCA&GT；&GT；HDCA&GT；TDCA、GCDCA&GT、UDCA、CA。值得注意的是，DCA和CA在这方面有明显的区别。这种差异也是从结合的CDCA的Eadie-Scatchard图中DCA相对于其相应的结合/自由比借助于^&lt；14&gt；C-CDCA的非竞争性抑制模式而得到的。将其对胆汁酸的捕集能力与豆类和谷类食品蛋白人工消化制备的各种抗性蛋白进行比较，发现其对次生胆汁酸的亲和力远低于大豆抗性蛋白。大多数从肠道吸收中逃逸出来的初级胆汁酸会被肠道细菌进行脱羟基，并转化为次级胆汁酸，这对致癌具有相当大的风险。考虑到抗药性蛋白对次级胆汁酸的高度亲和力，在日常饮食习惯中连续摄入这些蛋白，除了改善血脂或胆固醇血症外，还有助于预防癌症。较少