Protease is the general name of a class of enzymes that hydrolyze protein peptide chains.Divided according to the way of peptide degradationEndopeptidaseAnd telopeptidases.The former can cut the polypeptide chain with large molecular weight from the middle to form prion and peptone with small molecular weight;The latter can be divided intoCarboxypeptidaseandAminopeptidaseThey hydrolyze peptide chains one by one from the free carboxyl end or free amino end of polypeptidesamino acid。
Chinese name
protease
Foreign name
Protease
Alias
Subtilis lysozyme;Prion lyase;Sutilanase;Derived from Bacillus licheniformis
The function of trypsin is to hydrolyze proteins between cells so as to disperse cells.Different tissues or cells react differently to trypsin.The activity of trypsin dispersing cells is also related to its concentration, temperature and action time. At pH 8.0 and temperature 37 ℃, the action ability of trypsin solution is the strongest.When using trypsin, the concentration, temperature and time should be well controlled to avoid cell damage caused by excessive digestion.Since Ca2+, Mg2+, serum and protein can reduce the activity of trypsin, BSS without Ca2+and Mg2+should be selected when preparing trypsin solution, such as D-Hanks solution.When digestion is terminated, the trypsin pair can be terminated with serum culture solution or trypsin inhibitorCellsRole of.
1. Weigh trypsin: according to the trypsin solution concentration of 0.25%, use an electronic balance to accurately weigh the powder into the double distilled water (if double distilled water is used, adjust the PH to about 7.2) or PBS (D-hanks) solution in the small beaker.Mix well, and place it at 4 ℃ overnight.
2. Filtration and disinfection with injection filter: The prepared trypsin solution should be filtered and sterilized with injection filter (0.22 micron microporous membrane) in the ultraclean table.Then sub packed into vials and stored at - 20 ℃ for future use.
Trypsin can catalyze the hydrolysis of specific peptide bonds of proteins. This catalytic process does not require energy, will not inactivate the enzyme, and will not change its shape or hydrolyze itself.The binding between the substrate and the active center of the enzyme is reversible. This binding enables the specific peptide bond of the protein to be activated due to bending deformation, which makes it more vulnerable to the attack of water molecules, forming amino and carboxyl groups respectively and breaking to obtain small molecular polypeptides or amino acids.Different proteases can act on peptide bonds composed of different amino acids, so trypsin cannot act on all peptide bonds.
Protease content
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The depilation and softening of leather industry have made great use of protease, which not only saves time, but also improves the working and sanitary conditions.The protease can also be used for silk degumming, meat tenderization and wine clarification.It can be used as medicine clinically, such as pepsin for dyspepsia and acid protease for treatmentbronchitis, treated with proteaseVasculitisAnd the purification of external suppurative wounds and the treatment of pleural serous adhesion with trypsin and chymotrypsin.Enzymatic detergentIt is a new product in detergent, includingAlkaline proteaseIt can remove blood stains and protein stains on clothes, but pay attention not to contact the skin when using, so as not to damage the protein on the skin surface, causingrash、eczemaAnd other allergic phenomena.
Enzymes that catalyze the hydrolysis of proteins.There are many kinds, including pepsin, trypsin, cathepsin, papain and subtilisin.Protease has strict selectivity to the reaction substrate it acts on. A protease can only act on certain peptide bonds in protein molecules, such as peptide bonds formed by trypsin catalytic hydrolysis of basic amino acids.Proteases are widely distributed, mainly in human and animal digestive tract, and rich in plants and microorganisms.Due to the limited animal and plant resources, protease preparations are mainly produced by fermentation of microorganisms such as Bacillus subtilis and Aspergillus amphibians in industry.
extensive use
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Protease is one of the most important industrial enzymes, which can catalyze the hydrolysis of proteins and peptides and widely exists in animal viscera, plant stems and leaves, fruits and microorganisms.Proteases are widely used in cheese production, meat tenderization and vegetable protein modification.In addition, pepsin, chymotrypsin, carboxypeptidase and aminopeptidase are all proteases in the human digestive tract. Under their action, the protein ingested by the human body is hydrolyzed into small molecular peptides and amino acids.
At present, the proteases used in baking industry include mold protease, bacterial protease and plant protease.The application of protease in bread production can change the properties of gluten, and its action form is different from the action of force and the chemical reaction of reducing agent in bread preparation.The role of protease is not to destroy disulfide bond, but to break the three-dimensional network structure of gluten.The role of protease in bread production is mainly manifested in the dough fermentation process.Due to the function of protease, the protein in flour is degraded into peptides and amino acids to supply yeast with carbon source and promote fermentation[3]。
