Proteinase K (Proteinase K) is a protease with serine as its active center. It has broad substrate specificity, and it preferentially decomposes the ester and peptide bonds of the C-terminus of hydrophobic amino acids, sulfur-containing amino acids and aromatic amino acids.It can degrade proteins in a variety of different salts, denaturants, detergents, pH and temperature conditions. It has high activity in the buffers for extracting DNA and RNA and is mainly used for the digestion of proteins during the preparation of DNA and RNA.