求一篇与蛋白水解相关的英文文献

发布网友 发布时间：2022-04-19 23:53

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热心网友 时间：2023-09-16 06:35

According to the nature of various protease active site can be divided into the four categories:
Serine protease
In addition to its active center serine also included histidine and aspartate resies, such as the secretion of pancreatic enzymes and the various internal peptides and coagulation, hemolytic fiber, the complement system relevant to the protease.
Thiol protease
In addition to its active site cysteines outside the histidine resies is needed to participate in such plant sources, and some within the cell lysosomes cathepsin.
Aspartic protease
Their active center is composed of two aspartate resies, such as membrane secreted by the stomach pepsin, the kidney of angiotensin release of lysosomal enzymes in cells of certain tissue protease.
Metalloproteinase
In addition to metal ions outside the active site should also have other amino acids involved, such as pancreatic carboxypeptidase A active site including the zinc ion (Zn2 +) and glutamic acid, tyrosine resies. Most foreign peptide protease enzyme and some of the bacteria tend to fall into this category. In addition to the need for participation of various protease catalyzed peptide bond hydrolysis groups, the needs to have a certain combination with the substrate site, because these different parts to determine a variety of different protease specificity.
[Edit this section] according to their physiological function and specificity to classify
Since the discovery in the biological control protease important role in the process of post, but also its physiological function and specificity to classify.
Non-restrictive protease
Is the poor specificity of the enzyme, the hydrolysis of protein peptide in the very key to generate a variety of small peptides or free amino acids. The physiological function of these proteases are mainly involved in the degradation of protein, such as the secretion of gastrointestinal system of various proteases in vitro protein digestion of food intake decomposition; cell lysosomes of various organizations can remove all kinds of body protein metabolism in proct. The average life span of 120 days, red cells, the hemoglobin from the degradation of cathepsin.
Restriction protease
Enzyme is highly specific, only the role of a particular protein substrate, hydrolysis of which the specific peptide bond, and the resulting variety of physiological functions with different peptides or proteins. Such that protease in the body from the effects of biological control, they mostly belong to serine proteases, their specificity similar to trypsin of view, that is, only the role of arginine or lysine at the C-terminal peptide bond composed. These proteases and protease in general different, the common proteins such as casein or hemoglobin degradation activity is low or does not work, even if its specific hydrolysis of the protein substrate, the conformation has strict requirements on the substrate once the variability It can not be degraded, instead of limiting the hydrolysis of protease, on the contrary, the greater the variability of substrate proteins more easily hydrolyzed. Such as thrombin to fibrinogen when activated, the 150 arginine or lysine resies, only the hydrolysis of peptide bonds in fibrinogen α, β two-subunit near the N-Arg - Gly peptide bond, the release of bleeding fiber peptide A, B, so that soluble fibrinogen into the fibrin gel network.
[Edit this section] protease biological control
Many important physiological effects in vivo with protease related to the biological control, as listed in the table, when the organism to external stimuli when appropriate physiological responses to mobilize body protein to make the original does not have the biological activity of certain peptides or proteins, rapidly becoming the function The corresponding strong proct to meet the body's defense, survival and reproction purposes. Some of the mobilization process is relatively simple, can be accomplished through a catalytic reaction. If no activity in the gastrointestinal tract trypsinogen when its N terminal was enterokinase to remove a 6-peptide after hydrolysis to proce the active trypsin. There is a complex process required by many catalytic reactions, such as the reaction of blood coagulation and complement the process of around 10 or more components of participation.
[Edit this section] protease in the biological control system in the role of the characteristics
Biological effect is instantaneous
Through the activity of protein precursors in vivo activation and rapid emergence treatment. Because no transcription and expression through gene plication and other complicated process, it can quickly respond to external signals. In addition, this response is directed not reversible, unlike some other enzymes in vivo the biological control mechanisms, for example, phosphorylation of kinases, by protein phosphorylation and dephosphorylation to proce allosteric effects of biological control to be reversible .
To cascade expression
In the first stage reaction that is activated protein itself is a reaction catalyzed by the protease, thus playing the role of sequential amplification. Example 2 as part of the enzyme even at very low levels of catalytic reaction substrate molecules 1000, by two after the catalytic reaction amplified 100 times, and thus outside the body of the weak signal can also have a very strong biological effects.
Positive and negative feedback system exists
So that the entire multi-stage reaction system in the best condition, for example, blood coagulation process is activated thrombin catalyzed fibrinogen both so into fibrin, can activate coagulation factor Ⅷ and Ⅴ, which in turn further promote the activation of prothrombin, which is positive feedback, but thrombin itself can degrade prothrombin, so can no longer be active, it is negative feedback. The same catalytic activity in the precursor protein can sometimes arise when two or more different biological functions of the components such as adrenocorticotropic hormone, β-endorphin by promoting the same hormones and fat precursor protein hydrolysis. Sometimes involved in biological control of the protease proced by two different ways the same physiological effect, each other play a complementary role. For example, both the blood coagulation response to endogenous activation system, another organization exogenous activation system, both last through coagulation factor X to activate prothrombin. Protease is involved in a number of important biological control system, almost without exception, there are corresponding protease inhibitors. In some systems, if the corresponding protease inhibitor imbalance, and can cause disease. Such as congenital venous thrombosis and swelling of blood vessels and nerves of the body often is the lack of appropriate antithrombin Ⅲ and complement inhibitor, C1 inhibitor related.
[Edit this section] the application of protease
As a rich source of protein, in addition to the driven, plant extracts, it can also a large number of fermentation by bacteria, has been widely used in medical, food, leather, silk reeling instries, but also as an important biochemical reagents. For example, chymotrypsin for cataract surgery, to simplify operation, the success rate; trypsin on the removal of necrotic tissue, purulent inflammation, healing wounds have a demonstrable effect; urokinase, streptokinase for the treatment of venous thrombosis, vasculitis; kallikrein for the improvement of coronary artery disease, microvascular relaxation, decreased blood pressure; elastase has certain effect on the hardening of the arteries; bacterial protease hair removal for leather, silk adhesive glue. Rennet for making cheese procts; papaya or pineapple protease stabilizer for beer, can eliminate the beer cold and the resulting protein precipitation

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热心网友 时间：2023-09-16 06:36

水解酸化
hydrolysis-acidification reactor

A solid organic waste is fermented in water in two phases, a hydrolysis/acidification phase and a methane fermentation phase. Solid organic waste is introced in the first phase, of which waste at least 80% of the volume has a particle size larger than x mm, x being between 0.25 and 1.5 mm dependent on the introced solid organic waste. The waste in the first phase is continuously or periodically stirred and is screened for the removal of particles smaller than x mm with liquid, whereafter the smaller particles are separated from the liquid and the so-separated liquid is at least mainly supplied to the methane fermentation space, while the separated smaller particles are recirculated to the first phase reactor and/or discharged.

热心网友 时间：2023-09-16 06:36

hydrolysis-acidification reactor

A solid organic waste is fermented in water in two phases, a hydrolysis/acidification phase and a methane fermentation phase. Solid organic waste is introced in the first phase, of which waste at least 80% of the volume has a particle size larger than x mm, x being between 0.25 and 1.5 mm dependent on the introced solid organic waste. The waste in the first phase is continuously or periodically stirred and is screened for the removal of particles smaller than x mm with liquid, whereafter the smaller particles are separated from the liquid and the so-separated liquid is at least mainly supplied to the methane fermentation space, while the separated smaller particles are recirculated to the first phase reactor and/or discharged.