蛋白酶 来源于灰色链霉菌

Preparation Note

Collected from culture broth of S. griseus.

Quality

Contains calcium acetate.

Specificity

A mixture of at least three proteolytic activities including an extracellular serine protease. In general, serine proteases display a wide range of substrate specificities, which are believed to be mediated by an active site composed of one Asp, one His, and a Ser residue in the molecule. This enzyme prefers to hydrolyze peptide bonds on the carboxyl side of glutamic or aspartic acid.

Unit Definition

One unit will hydrolyze casein to produce color equivalent to 1.0 μmole (181 μg) of tyrosine per min at pH 7.5 at 37 °C (color by Folin-Ciocalteu reagent).

Application

Protease is an enzyme used to break down proteins by hydrolyzing peptide bonds. Protease is used to degrade proteins, to study protease inhibitors and to study thermal inactivation kinetics. Protease is used in nucleic acid isolation procedures in incubations. Protease from Streptomyces griseus has been used in crystallographic and kinetic investigations of the covalent complex formed by tetrapeptide aldehydes and serine proteases^[2].

Protease is typically used in nucleic acid isolation procedures in incubations of 0.5-3.0 hours supplemented with 0.2% sodium dodecyl sulfate and 10 mM EDTA.

The enzyme from Sigma has been used for the digestion and analysis of antithrombin-heparin complexes.^[1] It has also been used for the isolation of enzyme-resistant starch.^[3]

This enzyme is more active at a higher pH range than the known alkaline protease, showing the proteolytic activity even in 0.2N NaOH solution. This enzyme is useful for proteolysis of insoluble protein and for structure investigation of protein.

Biochem/physiol Actions

Protease catabolizes proteins by hydrolysis of peptide bonds. Proteases are inactivated by serine active-site inhibitors, such as phenylmethylsulfonyl fluoride (PMSF) and diisopropylfluorophosphate. Protease from Streptomyces griseus is a mixture of at least three proteolytic activities including an extracellular serine protease. Serine proteases display a wide range of substrate specificities, which are believed to be mediated by an active site composed of one Asp, one His, and a Ser residue in the molecule. This enzyme prefers to hydrolyze peptide bonds on the carboxyl side of glutamic or aspartic acid.

This product is a mixture of at least three caseinolytic activities and one aminopeptidase activity.^[4] The caseinolytic enzymes were named asStreptomyces griseus Protease A, Streptomyces griseus Protease B andStreptomyces griseus Trypsin. This product may be used when extensive or complete degradation of protein is required. This protease mixture is highly nonspecific and can digest casein to the extent of >70% as mono-amino acids.

Physical properties

Completely inactivated by heating above 80 °C for 15-20 minutes.