Proteinase K

Boster’s Proteinase K is a Tris-HCl buffered concentrated enzyme stock solution that is to be used as assistant pre-treatment reagent in Western blot and IHC assay procedures. Cited in 12 publication(s).

Product Info Summary

SKU AR0056
Pack size 5 mL
Form Supplied1:100 Concentrated stock solution of Proteinase K in Tris-HCl buffer
Reagent Type Assistant Reagent


Physical State Liquid
Pack Size 5mL
Form Supplied 1:100 Concentrated stock solution of Proteinase K in Tris-HCl buffer
Content 10 mg/ml Proteinase K, 50mM Tris-HCl (pH 7.5), 150mM NaCl
Reagent Type Assistant reagent
Enzyme Concentration 10 mg/ml
Recommended working concentration 50-100µg/ml for protein removal and enzyme inactivation; up to 2mg/ml for tissue treatment
pH 7.5-9.0
Storage Store at -20°C for one year
Equivalent Abcam (Product No. ab64220)
Cite This Product Proteinase K (Boster Biological Technology, Pleasanton CA, USA, Catalog # AR0056)

Assay Principle

Proteinase K is a Tris-HCl buffered concentrated enzyme stock solution that is to be used as assistant pre-treatment reagent in Western blot and IHC assay procedures for general protein digestion in tissue lysates during sample preparation, for eliminating comigrating protein antigens prior to SDS-PAGE, as well as for proteolytic antigen retrieval prior to antibody staining in IHC.


•Proteolytic induced epitope retrieval (PIER);

•Proteolytic inactivation of endonucleases during DNA/RNA isolation and tissue sec•tions preparation for in-situ hybridization;

•Determination of enzyme localization;

•General protein digestion;

•Protein modification;

•Improve cloning efficiency of PCR products

Biochemical Information

CAS 39450-01-6
EC Numbers
Molecular Weight 28.93
Isoelectric Point 8.9
Enzyme Specificity Broad-spectrum serine protease
Cleavage Site Peptide bonds adjacent to the carboxyl group of aliphatic and aromatic amino acids with blocked alpha amino groups
Active Site Active-site catalytic triad Asp39-His69-Ser224
Enzyme activity & Stability Ca2+ improve stability
Stable in pH range 4–12; pH optimum 7.5 - 9.0
Stable and active in T range 37 - 65 °C; max activity at 50–60 °C
Stable and active under denaturing conditions: SDS; EDTA; urea; citrate; Triton X-100; Tween 20; Guanidinium chloride; Guanidinium thiocyanate; Sarkosyl; iodoacetic acid; TLCK; TPCK
Inhibition T > 65 °C; DIFP; PMSF; AEBSF; Hg2+
Enzyme Sources IntEnz

Enzyme activity in commonly used buffers

(Measured under the following conditions: pH = 8.0, 50 °C, 1.25 µg/ml protease K, 15 min incubation)

Buffer Proteinase K activity (%)
30 mM Tris·Cl 100
30 mM Tris•Cl; 30 mM EDTA; 5% Tween 20; 0.5% Triton X-100; 800 mM GuHCl 313
36 mM Tris•Cl; 36 mM EDTA; 5% Tween 20; 0.36% Triton X-100; 735 mM GuHCl 301
10 mM Tris·Cl; 25 mM EDTA; 100 mM NaCl; 0.5% SDS 128
10 mM Tris•Cl; 100 mM EDTA; 20 mM NaCl; 1% Sarkosyl 74
10 mM Tris•Cl; 50 mM KCl; 1.5 mM MgCl2; 0.45% Tween 20; 0.5% Triton X-100 106
10 mM Tris·Cl; 100 mM EDTA; 0.5% SDS 120
30 mM Tris·Cl; 10 mM EDTA; 1% SDS 203


Proteinase K is a is a subtilisin-related endolytic non-specific serine protease with broad cleavage specificity on native and denatured proteins that cleaves ester and peptide bonds at the carboxylic sides of N-substituted hydrophobic aliphatic and aromatic amino acids.
General features and behavior: It has high activity and remains stable across a wide range of pH (4.0-12.5) and temperature (25°C to 65°C) conditions and is suited to short digestion times. It remains active in the presence of various detergents and denaturants, and is even stimulated when up to either 2% SDS, 4 M urea, 3 M Guanidinium chloride, or 1 M Guanidinium thiocyanate are included in the reaction, making the substrate cleavage sites more accessible. Calcium ions, though contributing to Proteinase K stability, are not essential to the function of the enzyme, therefore it is also active in buffers containing metal chelating agents such as EDTA and may be used to inactivate calcium-dependent nucleases. It is also not inhibited by sulfhydryl reagents, trypsin and chymotrypsin inhibitors, or by serine protease inhibitors like Nα-Tosyl-Lys Chloromethyl Ketone (TLCK) and Nα-Tosyl-Phe Chloromethyl Ketone (TPCK). Proteinase K is however inhibited by temperatures above 65 °C, trichloroacetic acid (TCA) or the serine protease-inhibitors diisopropylfluorophosphate (DIFP), phenylmethylsulfonyl fluoride (PMSF), or 4- (2-Aminoethyl) benzenesulfonyl fluoride (AEBSF).
Applications: Proteinase K is widely used to digest endogenous DNases and RNases and remove protein contaminations during nucleic acid isolation and purification from cell lysates and for preparation of tissue sections for in situ hybridization. Proteinase K is suitable for isolating PCR and RT-PCR templates. It has been used to remove endotoxins bound to cationic proteins such as lysozyme and ribonuclease. It has been reported useful for determination of enzyme localization on membranes, as well as for mitochondria isolation. In IHC it is used for treatment of paraffin embedded tissue sections to retrieve masked antigen binding sites for antibody labeling. In Western blot it is used as assistant reagent for general protein digestion during sample preparations.

Product Images

AR0056 has been cited in 12 publications:

*The publications in this section are manually curated by our staff scientists. They may differ from Bioz's machine gathered results. Both are accurate. If you find a publication citing this product but is missing from this list, please let us know we will issue you a thank-you coupon.

The activation and function of IL-36γ in neutrophilic inflammation in chronic rhinosinusitis

Sun M,Lu Z,Cai P,Zheng L,Zhao J.Salidroside enhances proliferation and maintains phenotype of articular chondrocytes for autologous chondrocyte implantation (ACI) via TGF-β/Smad3 Signal.Biomed Pharmacother.2020 Feb;122:109388.doi:10.1016/j.biopha.2019.109
Species: Rat

Zhang Z, Wang J, Song Z, Wang Y, Cheng Z, Guo Q, Wang E, Jian Y, Lei W. Downregulation of MicroRNA-199a-5p Alleviated Lidocaine-Induced Sensory Dysfunction and Spinal Cord Myelin Lesions in a Rat Model. Toxicol Lett. 2020 Nov 6:S0378-4274(20)30458-6. doi:
Species: Rat

Protective effects of baicalin on rabbit articular chondrocytes in vitro

The Protective Effects of Salubrinal on the Cartilage and Subchondral Bone of the Temporomandibular Joint under Various Compressive Mechanical Stimulations

A novel method for detection of HBVcccDNA in hepatocytes using rolling circle amplification combined with in situ PCR

Correlation between expression and differentiation of endocan in colorectal cancer

Wang Z, Yi X, Du L, Wang H, Tang J, Wang M, Qi C, Li H, Lai Y, Xia W, Tang A. Virol J. 2017 Oct 6;14(1):193. doi: 10.1186/s12985-017-0859-5. A study of Epstein-Barr virus infection in the Chinese tree shrew(Tupaia belangeri chinensis)

Han L, Chen W, Xia Y, Song Y, Zhao Z, Cheng H, Jiang T. Am J Transl Res. 2018 Apr 15;10(4):1172-1183. eCollection 2018. MiR-101 inhibits the proliferation and metastasis of lung cancer by targeting zinc finger E-box binding homeobox 1

Li W, Zhang X, Wang J, Li M, Cao C, Tan J, Ma D, Gao Q. Oncotarget. 2017 Oct 6;8(56):96035-96047. doi: 10.18632/oncotarget.21635. eCollection 2017 Nov 10. TGFβ1 in fibroblasts-derived exosomes promotes epithelial-mesenchymal transition of ovarian ...

Wang M, Li M, Yan P, Luo Q, Zhang Y, Du Z. J Ophthalmol. 2017;2017:6067890. doi: 10.1155/2017/6067890. Epub 2017 Feb 9. The Effect of High Intensity Focused Ultrasound Keratoplasty on Rabbit Anterior Segment

Cheng O, Li Z, Han Y, Jiang Q, Yan Y, Cheng K. Brain Res. 2012 Aug 27;1470:111-8. Doi: 10.1016/J.Brainres.2012.06.026. Epub 2012 Jul 11. Baicalin Improved The Spatial Learning Ability Of Global Ischemia/Reperfusion Rats By Reducing Hippocampal Apo...

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