The role of proteinase K in nucleic acid detection

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For the prevention and control of the new crown epidemic, the focus is on how to effectively control and quickly and accurately detect. The key is to be able to extract the specified sample, and to exclude impurities (irrelevant protein, nuclease) in the sample, and the most commonly used enzyme when we exclude impurities is proteinase K.


Proteinase K (Proteinase K) is a serine protease with a wide cleavage activity. The main cleavage point is the carboxy terminal peptide bond of anhydrous amino acids such as aliphatic and aromatic. Because the enzyme can degrade keratin, it was named Proteinase K. According to its protein crystallization and molecular structure studies, the enzyme belongs to the subtilis protein family. The active site has the characteristic catalytic triple amino acid Asp39-His69-Ser224, which has extremely high enzyme activity and wide substrate specificity, and can remove RNA. The activity of enzymes and DNases, which are generally used to degrade proteins in biological samples, can be purified from Candida albicans Limbertii with calcium ions as a protective agent.


In the detection of the new coronavirus, the processing, extraction, and amplification of the nucleic acid amplification test are very risky. Therefore, the virus must be inactivated before the amplification. Generally, the virus sampling solution that comes with the new coronavirus nucleic acid reagent kit is used. For virus inactivation, proteinase K is a very important component in the virus preservation solution.

The virus preservation solution has two functions:

1) Non-inactivated virus preservation solution: Directly lyse the virus to release nucleic acid and eliminate RNase to prevent virus RNA degradation.

2) Inactivated virus preservation solution: inactivate the virus, denature the protein of the virus, make it inactive and "dead", and no longer be infectious, improving the safety of the transportation and detection stage.

Proteinase K can degrade histones that are tightly bound to nucleic acids, separate DNA and proteins, so that DNA can be better extracted; in addition, proteinase K can degrade RNA hydrolase (RNase) activity, inhibit RNase hydrolysis of template RNA, and is used in RNA extraction And it plays an indispensable role in the detection process, so the significance of proteinase K in the new crown detection is very important.

Storage of proteinase K

The dry powder state can be stored at low temperature at 0~4℃. After dissolving, dispense into appropriate volume and store at -20°C. Transportation can be carried out at room temperature. Under the correct storage conditions, the validity period of the dry powder state can be up to two years. The liquid state is valid for half a year at -20°C. After opening the package, if it is placed in an environment of 2~8℃ for more than a week, it is recommended to filter and sterilize or add a stabilizer such as 0.5% sodium azide to prevent microbial contamination.

Desheng Company not only produces proteinase K, but also developed and produced virus preservation solutions at the beginning of the epidemic, including inactivated and non-inactivated types, which have been well received by new and old customers. With the spread of the epidemic abroad, Desheng's virus preservation solution has also gone out of the country and sold overseas.