Explain the Absorption of Protein?
Although single amino acids are liberated in the intestinal contents, there is insufficient power in the enzymes of the pancreatic juice to render all of the amino acids singly for absorption. The brush border of the absorptive cell, therefore not only absorbs the single amino acid but also the di- and tripeplides. In the process of absorbing these small peptides, it hydrolyzes them to their constituent anlino acids. There are specific transport systems for each group of functionally similar amino acids and peptides.
The site of absorption is the 'small intestine'. The process of absorption requires energy. It is observed that L-isomers (natural isomers) of amino acids are more rapidly absorbed than D-amino acids and are hence biologically more important. What are L and D isomers of amino acids? These isomers are transported by an active carries system against a concentration gradient. Similarly, neutral amino acids are more rapidly absorbed than the basic amino acids and in general, amino acids compete with one another for absorption. In several instances, the carrier is a shared one, that is, the carrier transports more than one amino acid. Vitamin B6 is essential for amino acid absorption.