Abstract:Proteinase K， a kind of serine proteinases with high activity， is not only widely used in the related experiments of molecular biology and cell biology， but also increasingly applied to food， agriculture， medicine and other fields. In essence， proteinase K can degrade histone， nuclease and other proteins that affect the ex－ traction of nucleic acid， which is the main foundation of its application in various fields. At present， there is not any uniform standards about proteinase K production specifically used for the extraction of nucleic acid in Chi－ na， which causes much inconvenience and difficulty in the circulation， application and supervision. In this es－ say， the property and detection method about enzyme activity of proteinase K were analyzed， and its actual ap－ plication conditions in the extraction of nucleic acid from different biomaterials were also summarized. The paper was aimed at providing some reference for the formulation of method standards and production standards related to proteinase K used for the extraction of nucleic acid.