Interaction of the protease resistant proteins with the intestinal mucosa membrane proteins (1036.3)

Abstract

Many studies have shown that some substances in soy, such as digested peptides or isoflavones from soy have effects on satiety control and nutrient absorption functions. However, it is still clearly not known how soy can control those functions. We have shown that some of the soluble soy proteins were resistant to proteases, such as pepsin and pancreatine, in the in vitro digestion analysis. We named these proteins as PRFPs (protease‐resistant food proteins), and postulated that PRFPs can interact with the mucosa membrane on the villi or microvilli in the small intestine to trigger the biological activities mentioned above. The interactor proteins on the intestinal membrane and soy proteins were identified by crosslinking and mass spectrometric analysis. The identified intestinal membrane proteins were mostly channel proteins and galectins. The soy partners to the membrane proteins were found to be glycinin and beta‐conglycinin, which are the majority proteins of soy. Phosphoproteomic changes in the intestinal cell line upon soy protein treatment were tested. After the soy protein treatment, phosphoproteins enriched from the cell extract by IMAC column were separated on 2D gels and compared for the up and down regulations. Interestingly, many of the proteins involved in protein folding or energy metabolism were significantly phosphorylated by soy protein treatment to the cell line.For further studies, detailed cell signaling pathway/mechanism by soy PRFPs treatment to the cells are under investigation in view of revealing the function of soy proteins in satiety, nutrient absorption, and others.