Abstract
Currently obtained findings regarding the properties of the H+/peptide cotransport system in the intestinal brush border membrane gave new knowledge on the significance and importance of the system. Coexistence and cooperation of both Na+-dependent amino acid transport system and the H+-dependent peptide transport system enable the intestine to absorb amino acids very efficiently regardless of their chemical properties. Heterologous inhibition of amino acid transport by sugars is also overcome by the presence of the peptide system. The activity of H+ secretion by the absorbing cells has also been recognized to be very important for this cooperation. Other physiological factors including mucin secretion and maintenance of the transmembrane potential are also related to the integrated function of absorption of protein hydrolysates. Efficient absorption of protein hydrolysates depends on all above functions, together with other mechanisms, such as two-step digestion process, morphology of the brush border and the motility of the intestine, and all these factors are considered to effectively suppress bacterial growth in the small intestine and overcome the competition for nutrients with bacteria.
