Proteinase K is a serine protease with broad cleavage activity. It finds widespread applications, including the preparation of chromosomal DNA for pulse electrophoresis, protein imprinting, and removal of nucleases in DNA and RNA preparations. Proteinase K typically works at concentrations of 50–100 μg/ml and exhibits activity over a wide pH range (pH 4-12.5).

        Proteinase K has been extensively utilized in industries such as leather, fur, silk, pharmaceuticals, food, and brewing. In the leather industry, it is used for depilation and softening, saving time and improving labor hygiene conditions. Proteinase K is also employed in silk degumming, meat tenderization, and alcohol clarification. In clinical settings, it is used medicinally—for example, gastric protease for treating indigestion, acidic protease for bronchitis treatment, and elastase for vasculitis treatment. Additionally, pancreatic protease and pancreatic casein protease are used for purifying surgical suppurative wounds and treating pleural adhesions. Enzyme-containing laundry detergents are a new product in the detergent industry, containing alkaline proteases capable of removing blood stains and proteinaceous residues from clothes. However, it is important to avoid skin contact during use to prevent allergic reactions such as rashes and eczema caused by damaging the proteins on the skin surface.