Proteinase K

Proteinase K is a highly active, broad-spectrum serine protease belonging to the subtilisin family. It preferentially hydrolyzes ester and peptide bonds on the C-terminal side of hydrophobic, aromatic, and sulfur-containing amino acid residues to digest proteins into short peptides. Structurally, it features the conserved Asp39-His69-Ser224 catalytic triad and contains two Ca2+-binding sites near the active center. These calcium-binding sites stabilize the enzyme, allowing it to retain robust activity under diverse operating conditions.