Classification and efficacy of proteases

Protease pictures Image: Protease structural formula Protease, English name Protease, is a class of enzymes that hydrolyze protein peptide chains. There are many ways to classify proteases: according to the way it hydrolyzes peptides, it is generally divided into endopeptidases and exopeptidases. As the name suggests, it can be seen that endopeptidases are inside protein molecules, cutting large-molecular-weight polypeptides into small-molecular-weight prions and peptones. Exopeptidases hydrolyze free carboxyl groups or peptide bonds on amino groups from the outside, that is, at the end of protein molecules, to form amino acids. Therefore, exopeptidases are divided into carboxyl peptidases and aminopeptidases; according to the activity of proteases and the optimal pH value, there are aspartate proteases, metalloproteases, mercaptoproteases, and serine proteases; proteases can also be divided into acidic, neutral, and basic, which are distinguished according to the optimal pH value of their reactions. In fact, according to the data of Huayuan Network, there are more than 60 kinds of proteases with different Cas numbers alone. Endopeptidase is the most widely used in industry. Proteases are widely distributed, naturally occurring in animals and plants, and are also widely present in microorganisms. In industry, proteases are generally produced by microbial fermentation, mainly using bacteria (Bacillus subtilis) and molds (Aspergillus subtilis), and sometimes yeast and actinomycetes. There are many types of proteases, and the catalytic action of different proteases is very selective. Generally, a protein enzyme only acts on certain specific peptide bonds. Pepsin, also known as gastric enzyme, is generally derived from pigs. It is mainly used in clinical practice to supplement pepsin in patients who lack pepsin to improve indigestion and other related symptoms. It can also be used to promote the rapid absorption of injectable liquid in the human body and relieve swelling and pain. Trypsin can hydrolyze proteins between cells and separate different cells. The main factors for separating cell activity are temperature, concentration and time of action. The optimal reaction temperature is 37 degrees Celsius, PH = 8.0, so sometimes in order to avoid excessive separation, it is necessary to control the relevant reaction conditions. Trypsin also has a wide range of applications in medicine: Trypsin can not only help digestion like digestive enzymes, but also promote the decomposition of thick sputum and blood clots, which can be quickly eliminated after dilution; Trypsin can also play an anti-inflammatory effect and accelerate wound healing by promoting the proliferation of wound granulation tissue. When configuring trypsin solution in actual use, avoid choosing BSS containing calcium ions and magnesium ions to ensure that the activity of trypsin will not be reduced. If you need to stop the digestion of trypsin, you can choose serum culture medium or use corresponding enzyme inhibitors. In addition, due to the strong selectivity of protease, the reaction intensity of trypsin to different tissues is also different, and trypsin cannot work on all tissues. 1. Weigh trypsin: Prepare double-distilled water with a pH of 7.2, or PBS (D-hanks), weigh an appropriate amount of trypsin, control the concentration to 0.25%, stir and mix well, refrigerate overnight, and control the temperature at 4 degrees Celsius. 2. Suction filtration and disinfection: Prepare the injection filter (0.22 micron microporous filter membrane), filter and disinfect the trypsin solution in the ultra-clean table, sub-pack it in special vials, freeze store, and control the temperature at -20 degrees Celsius. Mold protease, bacterial protease and plant protease are commonly used in the baking industry to disconnect gluten by separating cells to form a network, increase the elasticity of gluten, and at the same time provide yeast carbon source by hydrolyzing protein to promote the fermentation of dough.