Amino acids are the fundamental building blocks of protein. Amino acids forms into chains called as peptides, these peptides form chains which are called as polypeptides, a group of polypeptides forms protein.
The food that is being chewed mixes with digestive juices in the mouth and the process of digestion starts in mouth itself. We will be discussing the digestion process of proteins.
The protein that is consumed travels down to stomach and mixes with Hydrochloric acid(HCl) in the stomach, HCl denatures the protein and caused the protein to unfold. This unfolding of protein makes polypeptide chains visible, Pepsin in the presence of acidic environment breaks peptide bonds into shorter polypeptides. These polypeptides travel to small intestine.
Chymotrypsin and Trypsin are the two major pancreatic enzymes in the small intestine. These two enzymes along with other protein digesting enzymes, breaks polypeptides into tripeptides and dipeptides which are in turn broken into amino acids. These amino acids are absorbed into blood stream and transported to the respective cells where proteins are made using these amino acids.