trypsin

Trypsin is a type of serine protease enzyme from the PA clan superfamily found in the digestive system of many vertebrates, where it begins the digestion of proteins by hydrolysis, cutting long chains of amino acids into smaller pieces. Trypsin is formed in the small intestine when its proenzyme, known as trypsinogen and produced by the pancreas, is activated. Trypsin cuts peptide chains mainly at the carboxyl side of the amino acids lysine and arginine. It is widely used in numerous biotechnology applications in clinical and research laboratories. The enzymatic action of trypsin is commonly referred to as trypsinogen proteolysis or trypsinization, and proteins that have been digested or treated with trypsin are said to have been trypsinized.

Trypsin was discovered in 1876 by Wilhelm Kühne. Many sources incorrectly claim that Kühne derived the name trypsin from the Ancient Greek word for rubbing, tripsis, because the enzyme was first isolated by rubbing the pancreas with glass powder and alcohol; in fact Kühne named trypsin from the Ancient Greek word thrýpto, meaning "I break" or "I break apart".