Enzyme-degradable

Enzyme degradation of leaf protein may occur during emshing and separation from the fiber. The amino acids produced by this enzyme action are soluble in the juice and may be lost unless all of the juice is recovered. 

Of particular importance for modifications of starch are the enzyme degradation products such as glucose symps, cyclodextrins, maltodextrins, and high fmctose com symps (HFCS). Production of such hydrolysis products requites use of selected starch-degrading enzymes such as a-amylase,... 

P-amylase, and debranching enzymes. Conversion of D-glucose to D-fmctose is mediated by glucose isomerase, mosdy in its immobilized form in columns. Enzymic degradation of starch to symps has been well reviewed (116—118), and enzymic isomerization, especially by immobilized glucose isomerase, has been fiiUy described (119) (see Syrups). 

BVdU is degraded by thymidine phosphorylase more rapidly than the natural substrate, thymidine. This rapid enzymic degradation may present a problem in its clinical use. Moreover, herpes vimses develop resistance to BVdU, apparendy because of mutant vimses that have lower thymidine kinase activity. G. D. Seade has dropped further development of BVdU because of increased animal tumor incidence induced by prolonged dosing (1). 

Enzymes Degrading Macromolecules. Enzymes that degrade macromolecules such as membrane polysaccharides, stmctural and functional proteins, or nucleic acids, have all shown oncolytic activity. Treatment strategies include the treatment of inoperable tumors with pepsin (1) antitumor activity of carboxypeptidase (44) cytotoxicity of ribonudease (45—47) oncolytic activity of neuraminidase (48—52) therapy with neuraminidase of patients with acute myeloid leukemia (53) antitumor activity of proteases (54) and hyaluronidase treatment in the management of human soHd tumors (55). 

The absolute quantity of an enzyme reflects the net balance between enzyme synthesis and enzyme degradation, where 4 and represent the rate constants for the overall processes of synthesis and degradation, respectively. Changes in both the 4 and of specific enzymes occur in human subjects. 

Fic. 12.—Sequence of the Glycosphingolipid Shown in Fig. 11, after Enzymic Degradation with a-D-Galactosidase. (Cleavage points, and the masses of fragment ions of the permethy-lated derivative, are shown.)... 

Typical attributes for evaluating food quality are safety, shelf life, color, taste, flavor, texture, health, and convenience. The level of a quality attribute is determined by levels of physical, microbial, physiological, chemical, and biochemical food processes, product composition, and applied technological conditions. For example, a combination of enzyme-degrading colorants, compositions and concentrations of pigments, and food structure properties contribute to a certain color level perceived by consumers. Depending on the match of expectation and experience, certain attributes will or will not be perceived as quality. ... 

PECTEV FRAGMENTS, RESISTANT TO ENZYMIC DEGRADATION DURING FRUIT PROCESSING... 

Finally, the A. aculeatus preparation was found to contain an enzyme releasing the dimer B-Xylp-(l-3)-GalAj, from a soluble soy cell wall polysaccharide. The enzyme was partially purified and appeared to be active towards saponified MHR and gum tragacanth as well. It was concluded that this enzyme degraded the xylogalacturonan part in MHR by an exo-fashion. 

J.W. Van de Vis, Characterization and mode of action of enzymes degrading galactan structures of arabinogalactans. Thesis Wageningen Agricultural University (1994). 

If we compare liquefaction to maceration, more activities are needed to liquefy the cell wall. Since 1991, new pectinases activities such as rhamnogalacturonase, pectin acetylesterase and xyloglucanases complex have been found to be important in the apple liquefaction by Henck Schols, Jean-Paul Vincken and Voragen [3]. The cellulose-xyloglucan complex accounts approximatively 57% of the apple cell-wall matrix. In a liquefaction process, an efficient enzymic degradation of this complex is crucial to increase the sugars extraction, to decrease the viscosity of the pulp then to be able to ultra-filtrate the juice without second depectinisation, at last to have negative alcohol tests required by some concentrate customers. 

Apples (Red Belle de Boskoop, Jonagold or Mutzu) were cut and milled (1.5 mm) and 5% (w/w) of a 2% ascorbic acid solution was added immediately. Enzyme preparations (25 mg enzyme protein / kg mash) were added and the mash was incubated for 2 hours at 20°C whereafter it was pressed. The resulting apple juice was pasteurised at 85°C to discontinue further enzyme degradation. The cloud was measured as turbidity in EF/F units [15]. The cloud stability was determined by a centrifugation test as the amount of turbidity remaining after centrifugation at 4,200 x g for 15 minutes [15]. 

Gierer, J. Opara, A. E. Enzymic degradation of lignin. Action of peroxidase and laccase on monomeric and dimeric model compounds. Acta Chem. Scand. 1973, 27,... 

The use of enzymes in industrial applications has been limited, because most enzymes degrade and deactivate under the extreme temperature or pH conditions found in many... 

The multilayer shells can also provide a protective barrier for the loaded enzyme in environments where enzyme-degrading substrates such as proteases may be present [67]. Dissolved catalase was inactivated immediately by protease, losing its entire activity within 60 min in solution. For catalase loaded in BMS spheres, inactivation is slower, with an activity loss of about 20 % in 60 min. Notably, a negligible decrease in... 

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