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Proteinase K from Tritirachium album

lyophilized powder, BioUltra, ≥30 units/mg protein, for molecular biology

Endopeptidase K
CAS Number:
Enzyme Commission number:
EC Number:
MDL number:


for molecular biology

Quality Level

product line



lyophilized powder

specific activity

≥30 units/mg protein

mol wt

28.93 kDa


Protein, ≥90% biuret


≤1 ppm DNA

foreign activity

DNAse, Nickase and RNAse, none detected

shipped in

wet ice

storage temp.


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Useful for the proteolytic inactivation of nucleases during the isolation of DNA and RNA.
Removes endotoxins that bind to cationic proteins such as lysozyme and ribonuclease A.
Reported useful for the isolation of hepatic, yeast, and mung bean mitochondria
Determination of enzyme localization on membranes
Treatment of paraffin embedded tissue sections to expose antigen binding sites for antibody labeling.
Digestion of proteins from brain tissue samples for prions in Transmissible Spongiform Encephalopathies (TSE) research.


5 mg in glass bottle
10, 25, 100, 500 mg in poly bottle
1 g in poly bottle

Biochem/physiol Actions

Proteinase K is a stable and highly reactive serine protease. Evidence from crystal and molecular structure studies indicates the enzyme belongs to the subtilisin family with an active-site catalytic triad (Asp39-His69-Ser224). It is stable in a broad range of environments: pH, buffer salts, detergents (SDS), and temperature. In the presence of 0.1-0.5% SDS, proteinase K retains activity and will digest a variety of proteins and nucleases in DNA preparations without compromising the integrity of the isolated DNA.

Unit Definition

One unit will hydrolyze urea-denatured hemoglobin to produce color equivalent to 1.0 μmole of tyrosine per min at pH 7.5 at 37 °C (color by Folin-Ciocalteu reagent).


Health hazard

Signal Word


Hazard Statements

Hazard Classifications

Eye Irrit. 2 - Resp. Sens. 1 - Skin Irrit. 2

Storage Class Code

11 - Combustible Solids



Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Personal Protective Equipment

dust mask type N95 (US), Eyeshields, Gloves

Certificate of Analysis

Certificate of Origin

  1. How should I prepare solutions of Product P2308, Proteinase K? 

    Solutions can be prepared in 25-50 mM Tris-HCl buffer, pH 8.0, containing 1-5 mM Calcium chloride.

  2. How should I store solutions of Product P2308, Proteinase K? 

    Stock solutions in 40% glycerol of at least 20 mg/ml can be stored in 10 mM Tris-HCl buffer, pH 7.5.with 1 mM  calcium acetate (see product P4850). Solutions are also stable at pH 8 at 4°C.

  3. What is the recommended pH range for Product P2308, Proteinase K? 

    Proteinase K is normally used in the pH range of 7.5-8.0.

  4. What amount of Product P2308, Proteinase K, should I use for nucleic acid preparations?

    Amounts for typical usage is 50-200 μg/mL.

  5. Which document(s) contains shelf-life or expiration date information for a given product?

    If available for a given product, the recommended re-test date or the expiration date can be found on the Certificate of Analysis.

  6. How do I get lot-specific information or a Certificate of Analysis?

    The lot specific COA document can be found by entering the lot number above under the "Documents" section.

  7. How do I find price and availability?

    There are several ways to find pricing and availability for our products. Once you log onto our website, you will find the price and availability displayed on the product detail page. You can contact any of our Customer Sales and Service offices to receive a quote.  USA customers:  1-800-325-3010 or view local office numbers.

  8. What is the Department of Transportation shipping information for this product?

    Transportation information can be found in Section 14 of the product's (M)SDS.To access the shipping information for this material, use the link on the product detail page for the product. 

  9. My question is not addressed here, how can I contact Technical Service for assistance?

    Ask a Scientist here.

Mamoru Oshiki et al.
Frontiers in microbiology, 9, 830-830 (2018-05-15)
Detection and genotyping of pathogenic RNA viruses in human and environmental samples are useful for monitoring the circulation and prevalence of these pathogens, whereas a conventional PCR assay followed by Sanger sequencing is time-consuming and laborious. The present study aimed
Mark F Sabbagh et al.
eLife, 7 (2018-09-07)
Vascular endothelial cell (EC) function depends on appropriate organ-specific molecular and cellular specializations. To explore genomic mechanisms that control this specialization, we have analyzed and compared the transcriptome, accessible chromatin, and DNA methylome landscapes from mouse brain, liver, lung, and
Margarita Zayas et al.
PLoS pathogens, 12(1), e1005376-e1005376 (2016-01-05)
Hepatitis C virus (HCV) nonstructural protein (NS)5A is a RNA-binding protein composed of a N-terminal membrane anchor, a structured domain I (DI) and two intrinsically disordered domains (DII and DIII) interacting with viral and cellular proteins. While DI and DII
Kumiko Muta et al.
Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association, 31(10), 1615-1623 (2016-05-18)
Although histone acetylation, an epigenetic modification, has been reported to be related to the progression of various diseases, its involvement in nephrosclerosis is unclear. Dahl salt-sensitive rats were used as a model of nephrosclerosis in this study. The rats were
Bahram Peivastegan et al.
BMC plant biology, 19(1), 262-262 (2019-06-19)
Stored potato (Solanum tuberosum L.) tubers are sensitive to wet conditions that can cause rotting in long-term storage. To study the effect of water on the tuber surface during storage, microarray analysis, RNA-Seq profiling, qRT-PCR and phytohormone measurements were performed


Enzymatic Assay of Proteinase K with Hemoglobin Substrate

Proteinase K (EC activity can be measured spectrophotometrically using hemoglobin as the substrate. Proteinase K hydrolyzes hemoglobin denatured with urea, and liberates Folin-postive amino acids and peptides. One unit will hydrolyze hemoglobin to produce color equivalent to 1.0 μmol of tyrosine per minute at pH 7.5 at 37 °C (color by Folin & Ciocalteu's Phenol Reagent).


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The GenElute Blood Genomic DNA Kit Protocol provides a simple and convenient way to isolate pure genomic DNA from fresh or aged whole blood.

GenElute™ Mammalian Genomic DNA Miniprep Kit Protocol

The GenElute Mammalian Genomic DNA Purification Kit Protocol describes the isolation of pure, high molecular weight DNA from a variety of mammalian sources.

Enzymatic Assay of Proteinase K (EC

Proteinase K (EC activity can be measured spectrophotometrically using hemoglobin as the substrate. Proteinase K hydrolyzes hemoglobin denatured with urea, and liberates Folin-postive amino acids and peptides. One unit will hydrolyze hemoglobin to produce color equivalent to 1.0 μmol of tyrosine per minute at pH 7.5 at 37 °C (color by Folin & Ciocalteu's Phenol Reagent).

GenElute™ Bacterial Genomic DNA Kit Protocol (NA2100, NA2110, NA2120)

GenElute™ Bacterial Genomic DNA Kit protocol describes a simple and convenient way for the isolation of pure genomic DNA from bacteria.

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