Proteolytic proteins

Proteolytic (protein-cleaving) enzymes also have applications in consumer products. For example, papain (from papaya extract) serves as a meat tenderizer. It cleaves the fibrous proteins, making the meat less tough. 

Protease inhibitors, which prevent proteolytic protein degradation. 

Walters Options The Alternative Cancer Therapy Book (1993) contains a short introduction to the subject under the section Metabolic Therapies, with the statement that proteolytic (protein-digesting) enzymes are believed to dissolve the walls of cancer cells, and that enzyme treatments are widely used in Europe. More specifically, enzymes are used variously in what are called Issels therapy, in Wheatgrass therapy, in the Gerson diet, in Kelley s therapy, and in Niepa- s therapy (Walters, 1993, pp. 86,147,198,207,216). It is noted furthermore that chranotherapy destroys the body s enzymes, that cooking destroys the enzymes in food, and that enzymes may be involved in the so-called spontaneous remission of cancer (Walters, 1993, pp. 155,201). Also noted, in the work of Hans Niepa-, is that the enzyme bromelain, derived from pineapple roots, will deshield cancer cells, as will beta-carotene (Walters, 1993, p. 222). 

Walker, A., and Anderson, C. (1985). Partial Proteolytic Protein Maps Cleveland Revisited, Anal. Biochem. 

Despite the occasional advantage of nonideal column behavior for specific peptide applications, such nonspecific interactions must be suppressed if ideal peptide/protein elution behavior is required, i.e., predictable elution times based on solute size only. The ability to predict the position and/or elution order of peptides during SEC of a peptide mixture would greatly simplify preliminary separation of peptides of interest from a chemical or proteolytic protein digest. Under conditions of ideal SEC, large peptide fragments can be quickly identified and removed. Thus, it is important to achieve a linear relationship between In... 

Hydrolyzed Vegetable Protein. To modify functional properties, vegetable proteins such as those derived from soybean and other oil seeds can be hydrolyzed by acids or enzymes to yield hydrolyzed vegetable proteins (HVP). Hydrolysis of peptide bonds by acids or proteolytic enzymes yields lower molecular weight products useful as food flavorings. However, the protein functionaHties of these hydrolysates may be reduced over those of untreated protein. 

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). 

In contrast to the nicotinamide nucleotide dehydrogenases, the prosthetic groups FMN and FAD are firmly associated with the proteins, and the flavin groups are usually only separated from the apoen2yme (protein) by acid treatment in water. However, in several covalently bound flavoproteins, the enzyme and flavin coen2ymes are covalently affixed. In these cases, the flavin groups are isolated after the proteolytic digestion of the flavoproteins. 

Protein G. This vitamin K-dependent glycoproteia serine protease zymogen is produced ia the Hver. It is an anticoagulant with species specificity (19—21). Proteia C is activated to Proteia by thrombomodulin, a proteia that resides on the surface of endothefial cells, plus thrombin ia the presence of calcium. In its active form, Proteia selectively iaactivates, by proteolytic degradation. Factors V, Va, VIII, and Villa. In this reaction the efficiency of Proteia is enhanced by complex formation with free Proteia S. la additioa, Proteia activates tissue plasminogen activator, which... 

Factors to be considered in maldng the selection of chromatography processing steps are cost, sample volume, protein concentration and sample viscosity, degree of purity of protein product, presence of nucleic acids, pyrogens, and proteolytic enzymes. Ease with which different types of adsorbents can be washed free from adsorbed contaminants and denatured proteins must also be considered. 

The ability to identify and quantify cyanobacterial toxins in animal and human clinical material following (suspected) intoxications or illnesses associated with contact with toxic cyanobacteria is an increasing requirement. The recoveries of anatoxin-a from animal stomach material and of microcystins from sheep rumen contents are relatively straightforward. However, the recovery of microcystin from liver and tissue samples cannot be expected to be complete without the application of proteolytic digestion and extraction procedures. This is likely because microcystins bind covalently to a cysteine residue in protein phosphatase. Unless an effective procedure is applied for the extraction of covalently bound microcystins (and nodiilarins), then a negative result in analysis cannot be taken to indicate the absence of toxins in clinical specimens. Furthermore, any positive result may be an underestimate of the true amount of microcystin in the material and would only represent free toxin, not bound to the protein phosphatases. Optimized procedures for the extraction of bound microcystins and nodiilarins from organ and tissue samples are needed. 

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