Protéinase K from Tritirachium album

Proteinase K, an extracellular endopeptidase is synthesized by the mold, Tritirachium album Limber. Proteinase K belongs to a new subfamily of the subtilisins. It is a 277 amino acid protein and is characterized with an unhydrolyzed protein chain and autolyzed polypeptide chains.

Proteinase K from Tritirachium album has been used in in situ detection of DNA fragmentation and in proteolysis experiments to measure the structural flexibility of interleukin 1ra (IL-1ra).

Utile pour l′inactivation protéolytique des nucléases lors de l′isolement de l′ADN et de l′ARN.

Utile pour l′inactivation protéolytique des nucléases lors de l′isolement de l′ADN et de l′ARN.
Élimine les endotoxines qui se lient aux protéines cationiques telles que le lysozyme et la ribonucléase A.
S′est avéré utile pour l′isolement des mitochondries hépatiques, de levure et de haricot mungo.
Détermination de la localisation des enzymes sur les membranes.
Traitement des coupes de tissus incluses en paraffine pour exposer les sites de liaison à l′antigène pour le marquage par anticorps.
Digestion des protéines des échantillons de tissu cérébral pour la recherche sur les prions responsables des encéphalopathies spongiformes transmissibles (EST).

Proteinase K from Tritirachium album has been used:

• to break down cardiac muscle during histopathology studies
• during the digestion of HEK-293 cells

The enzyme from Sigma has been used in the digestion of sealed cytosolic side out ER vesicles. It has been used to deproteinize dissected brain and/or whole pupae sections of honey bee prior to in situ hybridisation. This was done during the study of neuropeptide Y-like signaling, and nutritionally-mediated gene expression and behaviour in the honey bee.

Proteinase K has a broad specificity and degrades many proteins even in the native state. It mainly cleaves the peptide bond adjacent to the carboxyl group of aliphatic and aromatic amino acids with blocked alpha-amino groups. The optimum pH is between 7.5-9.0 and the isoelectric point is 8.9. Ca²⁺ (1-5 mM) is required for activation. Proteinase K is inhibited by DIFP or PMSF.

La protéinase K est une sérine protéase très stable et hautement réactive. Des études de cristallographie et de structure moléculaires ont indiqué que cette enzyme appartient à la famille des subtilisines, présentant une triade catalytique au site actif (Asp³⁹-His⁶⁹-Ser²²⁴). Elle est stable dans un vaste éventail d′environnements : pH, sels de tampon, détergents (SDS) et température. En présence de 0,1 à 0,5 % de SDS, la protéinase K reste active et peut digérer diverses protéines et nucléases dans les préparations d′ADN, sans compromettre l′intégrité de l′ADN isolé.

Solution in 40% (v/v) glycerol containing 10 mM Tris-HCl, pH 7.5, with 1 mM calcium acetate.

Proteinase K in solution is stable over a pH range of 4.0-12.5 (optimum pH 8.0), and is also stable over the temperature range of 25°C to 65°C during use. At pH 8.0, solutions will be stable for at least 12 months at 4°C. At pH 4-11.5, solutions containing Ca²⁺ (1-6 mM) are expected to be stable for several weeks. An 80% ammonium sulfate suspension stored at 4°C is stable for at least 12 months.

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).