Which is the digestive juice that only acts on proteins?

The digestive juice that only acts on proteins is trypsin. Trypsin is produced by the pancreas and secreted into the small intestine. It is an endopeptidase, which means that it cleaves peptide bonds within the interior of protein molecules. Trypsin acts on proteins that have been partially broken down by other digestive enzymes, such as pepsin from the stomach, and converts them into smaller peptides and amino acids.