Proteolytic enzymes and

Contraction of muscle follows an increase of Ca " in the muscle cell as a result of nerve stimulation. This initiates processes which cause the proteins myosin and actin to be drawn together making the cell shorter and thicker. The return of the Ca " to its storage site, the sarcoplasmic reticulum, by an active pump mechanism allows the contracted muscle to relax (27). Calcium ion, also a factor in the release of acetylcholine on stimulation of nerve cells, influences the permeabiUty of cell membranes activates enzymes, such as adenosine triphosphatase (ATPase), Hpase, and some proteolytic enzymes and facihtates intestinal absorption of vitamin B 2 [68-19-9] (28). 

Proteins have been hydrolyzed by treatment with sulfuric acid, hydrochloric acid, barium hydroxide, proteolytic enzymes, and other hydrolytic reagents, but no condition has been found which avoids some destruction or incomplete liberation of tryptophan, cystine, and some other amino acids. The early work on this problem has been reviewed by Mitchell and Hamilton (194). The literature and their own excellent experiments on the hydrolysis problem in relation to the liberation and destruction of tryptophan have been presented recently by Spies and Chambers (269). 

Plasminogen activator inhibitors have been shown to be present in a large variety of different cells and tissues. These inhibitors are thought to play an important role in regulating tissue fibrinolysis. One of these inhibitors has been purified from cultured bovine aortic epithelial cells. This inhibitor has been shown to be a serine protease inhibitor and inhibits the function of two proteolytic enzymes urokinase and tissue plasminogen activator, both of which cleave and activate plasminogen. The mechanism by which this inhibitor functions is very similar to that described above with a-l-PI. Thus, the inhibitor forms a binary complex with the proteolytic enzyme and thereby inhibits its activity. Again in a situation comparable to that with a-l-PI, it was found that when the purified bovine aortic epithelial inhibitor was exposed to Al-chlorosuccinimide,... 

Dialysis tubing is treated with glycerol and preservatives that need to be removed prior to use. Handle the membrane with gloves to avoid introduction of proteolytic enzymes and to reduce punctures. 

The stomach secretes pepsinogens, which are inactive proteolytic enzymes, and protons - the high concentration of which initiates hydrolysis of the pepsinogens to form active pepsins, which then continue their own activation, via an autocatalytic, hydrolysis (Appendix 4.1). 

Figure 21.18 Exit of tumour cells from a tumour into the bloodstream and entry into a new tissue for formation of a new tumour. Exit depends on lack of adhesion between tumour cells and release of proteolytic enzymes to destroy extracellular stroma. Cells travel to new tissue via the blood on lymph. They secrete proteolytic enzymes and bore a hole in the extracellular stroma of new tissue and then infiltrate and proliferate.

In this chapter, we wish to present the reader with an introduction to proteolytic enzymes, and some of their current and potential uses in various fields. It is our hope that this chapter will stimulate readers to consider proteolytic enzymes for biomass conversion as well as other possible uses. 

Corticotropin is rapidly inactivated by gastrointestinal proteolytic enzymes and therefore must be administered parenterally. It is rapidly removed from the circulation (Ti/2, 15 minutes) and is probably inactivated in body tissues, since no intact compound is found in the urine. 

The conditions necessary Tor the plastein reaction have been reviewed by Fujimaki et al. ( ), and compared to those necessary for proteolysis by Arai et al. ( ). The substrate for the synthetic reaction must consist of low molecular weight peptides, preferably in the tetramer to hexamer range. These are usually produced from proteins by protease action. A number of proteolytic enzymes and protein substrates have been investigated for producing plastein reaction substrates. The most often used proteases are pepsin JJ), and papain (12,13), but others... 

Kawai, M. 1973. Productivity of proteolytic enzymes and distribution of its milk clotting activity among the basidiomycetes. J. Agric. Chem. Soc. Japan 47, 467-472. 

Visser, S. 1981. Proteolytic enzymes and their action on milk proteins. A review. Neth. 

Let us now consider the retarding action of proteolytic enzymes on hydrolysis. Attention should be drawn to the fact that the carbonyl absorption band splits into two parts as a result of interaction of the cured KL-3 with proteolytic enzymes and kidney extract. Evidently it is associated with the specific interaction of the enzyme and urethane group in the polymer, the structure of which resembles the peptide group of a protein molecule. Owing to the specific action of the enzyme, this interaction does not accelerate the hydrolysis of urethane groups but even retards it owing to the shielding effect of the enzyme protein molecule. 

The role of zinc in the enzymes listed in Table 12 is very often that of a strong Lewis acid, in which substrates are coordinated, polarized and hence activated. In other cases, zinc may play a regulatory, structural or template role. Zinc may also have a structural function in other biological molecules, for example in the unwinding and subsequent rewinding of the double-stranded polymers involved in replication and transcriptional processes. There is also evidence for a role for zinc in the stabilization of membranes and cell walls.463 The high concentrations of zinc in certain snake venoms reflect the presence in the venom of proteolytic enzymes and hemorrhagic toxins that all require zinc for activity.464... 

Fig. 11.8 Structure of branched PEG which, because of its increased hindrance, prevents the approach of proteolytic enzyme and antibodies, increases the residence time in the systemic circulation, and sustains the biological activity longer as compared to linear PEG.

S. J. Taussig, M. M. Yokoyomo, A. Chinen, K. Onari, M- Yantiftlrido. and Y. Nishimoto. Bromelain a proteolytic enzyme and ils clinical application. A... 

The composition of the stratum corneum intercellular lipids may have profound effects on desquamation. In addition to modifying effects on, for example, proteolytic enzymes and their substrates,34 lipids may also be directly involved in corneocyte cohesion. The effects of cholesterol sulfate have already been mentioned. In addition to RXI, there are a number of other hereditary diseases with disorders of desquamation associated with disturbances in lipid metabolism. Furthermore, scaling as a result of treatment with lipid-lowering drugs has been observed (for review, see References 1 and 2). 

Free radicals, which damage tissues and disturb the balance between proteolytic enzymes and their inhibitors... 

Protein digestion refers to the method in which the protein of interest is first digested by a proteolytic enzyme and then analyzed by mass spectrometry. This process affords a peptide map that is unique for each protein and allows identification... 

Proteolytic Enzymes and Their Active-Site-Specific Inhibitors Role in the Treatment of Disease... 

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