539480

Proteinase K from Tritirachium album

• Synonym(s): Endopeptidase K
• CAS Number: 39450-01-6
• Enzyme Commission number: 3.4.21.14 (BRENDA, IUBMB)
• Enzyme Commission number: 3.4.21.64 (BRENDA, IUBMB)
• MDL number: MFCD00132129

Properties

• form: lyophilized solid
• Quality Level: 400
• specific activity: ≥30 mAnson units/mg dry wt; ≥40 mAnson units/mg protein
• mol wt: 28.93 kDa
• manufacturer/tradename: Calbiochem^®
• storage condition: OK to freeze
• color: white
• solubility: 50 mM Tris-HCl, 2 mM calcium acetate, pH 8.0: soluble
• foreign activity: DNase, none detected (nicking activity with pBR322, incubation for 6 h at 37°C); RNase, none detected (ribonuclease activity with MS2 RNA detected after incubation for 6 h at 37°C)
• shipped in: ambient
• storage temp.: 2-8°C

Description

General description

Serine protease that exhibits strong proteolytic activity on a wide variety of denatured and native proteins of high molecular weight. Because of its rapid proteolytic inactivation of endogenous nucleases, it can be used for isolation of mRNA and high molecular weight DNA. Preferentially cleaves bonds next to the carbonyl group of N-substituted hydrophobic, aliphatic, and aromatic amino acids. Inhibited by DFP, Hg²⁺, and PMSF. Not inactivated by metal chelators, sulfhydryl reagents, TLCK, or TPCK.

Application

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.

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.

Warning

Toxicity: Irritant (B)

Unit Definition

One mAnson unit is defined as the amount of enzyme that will liberate 1.0 µmol of Folin-positive amino acids (calculated as tyrosine) per min at 37°C, pH 7.5.

Physical form

Lyophilized from calcium acetate

Reconstitution

Following reconstitution, store in the refrigerator (4°C). Stock solutions prepared in 50 mM Tris-HCl, 2 mM calcium acetate, pH 8.0 are stable for up to 1 year at 4°C.

Other Notes

Watazu, Y., et al. 1993. J. Lab. Clin. Anal. 7, 81.
Lebherz, H.G., et al. 1986. Biochem. J.233, 51.
Ebeling, W., et al. 1974. Eur. J. Biochem.47, 91.

Legal Information

CALBIOCHEM is a registered trademark of Merck KGaA, Darmstadt, Germany

Safety Information

• Pictograms: GHS08
• Signal Word: Danger
• Hazard Statements: H315 - H319 - H334
• Precautionary Statements: P261 - P264 - P280 - P284 - P302 + P352 - P305 + P351 + P338
• Hazard Classifications: Eye Irrit. 2 - Resp. Sens. 1 - Skin Irrit. 2
• Storage Class Code: 11 - Combustible Solids
• WGK: WGK 1