Wang Jilite, Shimada Masaya, Kato Yukina, Kusada Mio, Nagaoka Satoshi
a Faculty of Applied Biological Sciences, Department of Applied Life Science , Gifu University , Gifu , Japan.
Biosci Biotechnol Biochem. 2015;79(3):456-61. doi: 10.1080/09168451.2014.978260. Epub 2014 Nov 6.
Dietary plant protein is well known to reduce serum cholesterol levels. Rice bran is a by-product of rice milling and is a good source of protein. The present study examined whether feeding rats a high-cholesterol diet containing 10% rice bran protein (RBP) for 10 d affected cholesterol metabolism. Rats fed dietary RBP had lower serum total cholesterol levels and increased excretion of fecal steroids, such as cholesterol and bile acids, than those fed dietary casein. In vitro assays showed that RBP strongly bound to taurocholate, and inhibited the micellar solubility of cholesterol, compared with casein. Moreover, the bile acid-binding proteins of the RBP were eluted by a chromatographic column conjugated with cholic acid, and one of them was identified as hypothetical protein OsJ_13801 (NCBI accession No. EAZ29742) using MALDI-TOF mass spectrometry analysis. These results suggest that the hypocholesterolemic action of the RBP may be caused by the bile acid-binding proteins.
众所周知，膳食中的植物蛋白可降低血清胆固醇水平。米糠是碾米的副产品，是一种优质蛋白质来源。本研究探讨了给大鼠喂食含10%米糠蛋白（RBP）的高胆固醇饮食10天是否会影响胆固醇代谢。与喂食酪蛋白的大鼠相比，喂食膳食RBP的大鼠血清总胆固醇水平较低，粪便类固醇（如胆固醇和胆汁酸）的排泄增加。体外试验表明，与酪蛋白相比，RBP与牛磺胆酸盐强烈结合，并抑制胆固醇的胶束溶解度。此外，RBP的胆汁酸结合蛋白通过与胆酸偶联的色谱柱洗脱，其中一种通过基质辅助激光解吸电离飞行时间质谱分析被鉴定为假定蛋白OsJ_13801（NCBI登录号EAZ29742）。这些结果表明，RBP的降胆固醇作用可能是由胆汁酸结合蛋白引起的。
