Evidence for the Existence of a Soybean Resistant Protein That Captures Bile Acid and Stimulates Its Fecal Excretion
Feeding HMF, an insoluble "high-molecular-weight fraction" from an industrial enzymatic digest of a soy protein isolate, increased the fecal excretion of bile acid concomitant with increased fecal nitrogen. An amino acid analysis revealed that this increased fecal nitrogen could be explained by an increase in the insoluble protein fraction. This suggests the existence of an indigestable protein or peptide that can be called a "resistant protein" in the feces. The presumed resistant protein was rich in hydrophobic amino acids and bound bile acid by hydrophobic interaction. The residual fraction of HMF obtained after <I>in vitro</I> pepsin and pancreatin digestion, showed higher <I>in vitro</I> bile acid-binding capacity and excreted more bile acid <I>in vivo</I> than HMF. Its amino acid composition was similar to that of the feces of rat fed with HMF. These results suggest that the fecal resistant protein with bile acid-binding ability could be derived from the indigestable fraction of HMF.
- Bioscience, biotechnology, and biochemistry
Bioscience, biotechnology, and biochemistry 70(12), 2844-2852, 2006-12-23
Japan Society for Bioscience, Biotechnology, and Agrochemistry