Application
Product P6556 is provided as a lyophilized powder. Product
P6556 has been used to break down human lens protein[1]. Protease footprinting
by Proteinase K digestion can reveal protein-protein surface
interactions.[2] The enzyme from Sigma has been used in the
pre-hybridization step of chicken embryos.[3] It has also been used for
the enrichment of PrPSc, a prion protein that is present in sheep,
hamster and mouse scrapie samples.[4]
Proteinase K is useful for the proteolytic inactivation of
nucleases during the isolation of DNA and RNA.
It is used for the removal of endotoxins bound to cationic proteins such as
lysozyme and ribonuclease A.
It is useful for the isolation of hepatic, yeast, and mung bean mitochondria
and is used to determine enzyme localization on membranes
It is used for the treatment of paraffin embedded tissue sections to expose
antigen binding sites for antibody labeling and
for digestion of proteins from brain tissue samples for prions in Transmissible
Spongiform Encephalopathies (TSE) research. Product P6556 is provided as a
lyophilized powder. Product P6556 has been used to break down human lens
protein[1].
Useful for the proteolytic inactivation of nucleases during
the isolation of DNA and RNA.
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 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
α-amino groups.[4][5][6] The optimum pH is between 7.5-9.0 and the
isoelectric point is 8.9[4] Ca2+ (1-5 mM) is required for
activation. Proteinase K is inhibited by diisopropyl fluorophosphate (DFIP),
and phenylmethanesulfonyl fluoride (PMSF).[5]
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.
Other Notes
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).
