The basic substrates for trypsin are food proteins, according to Worthington Biochemical Corporation. Trypsin is a digestive enzyme secreted by the pancreas. Trypsin separates large food proteins at their peptide bonds, breaking them into smaller polypeptide chains.
During digestion, trypsin is secreted into the duodenal section of the small intestine via the pancreatic duct. According to the RSCB Protein Data Bank, trypsin mainly acts next to the amino acids lysine and arginine in large protein chains. Throughout the digestive process, these severed protein segments are further acted on by additional digestive enzymes, ultimately producing individual amino acids. These small amino acids are absorbed through the lining of the small intestine and into the blood stream.