Enzymatic attack susceptibility

The categories of substrates which are used for assays of cellulase enzymes are shown in Table I. The use of crystalline, insoluble forms of cellulose as substrates makes assays difficult and has led to such trivial names as Avicelase activity. These assays are useful as indications of the capacity of an enzyme system to degrade native cellulose and indicate the presence of CBH enzyme which cannot be assayed in the presence of endoglucanases or / -glucosidase. The susceptibility to enzymatic attack generally increases with the hydration of the polymer chains that accom-... 

Susceptibility to Enzymatic Attack of Esters with Special Structural Features... 

Thermochemical treatment, such as with steam and dilute sulfuric acid, is a popular pretreatment process. This treatment opens the lignocellulosic pore structure and increases the susceptibility of biomass to enzymatic attack (2). This pretreatment step effectively hydrolyzes the biomass,... 

Non-enzymatic attack In non-enzymatic attack of minerals by microbes, reactive products of microbial metabolism come into play. The microbial enzymes responsible for metabolic product formation are located below the cell envelope, in the cytoplasm of prokaryotes (Bacteria and Archaea) and in cell organelles and/or the cytoplasm of eukaryotes (e.g. fungi, algae, lichens). In these instances of microbial attack, physical contact of the microbial cells with the surface of a mineral being attacked is not essential. The reactive metabolic products are formed intracellularly and are then excreted into the bulk phase where they are able to interact chemically, i.e. non-enzymatically, with a susceptible mineral. Depending on the type of metabolic product and mineral, the interaction with the mineral may result in mineral dissolution or mineral diagenesis by oxidation or reduction or acid or base attack. Mineral dissolution or diagenesis may also be the result of complexation by a microbial metabolic product with that capacity. In some instances mineral attack may involve a combination of some of these reactions. 

There are several types of biodegradable synthetic polymer with vulnerable chemical moieties susceptible to enzymatic attack. The most typical ones are aliphatic polyesters, such as poly(glycolic acid), poly(lactic acid), and poly(e-caprolactone). Highly isotactic-, syndiotactic- and atactic-homopolyesters of... 

Although a good correlation was found between the accessibility of the celluloses to a 30 A. molecule and their susceptibility to enzymatic attack, a further relationship was sought between reactivity and the surface area accessible to a molecule of a particular size. This would seem to be a more theoretically valid correlation to establish since the rate of a heterogeneous chemical reaction between molecules in solution and a solid is usually proportional to the available surface. The surface areas were calculated by incremental analysis of the accessibility curves in Figure 10, using the method discussed in the Experimental section and assuming that the surfaces in question are those associated with sheets... 

It is likely that the degradability of PET with hydrolases such as TfH strongly depends on the polymer crystallinity and the temperature at which the enzymatic degradation takes place [40]. The effective enzymatic PET hydrolysis will thus be expected to occur only below a certain critical degree of crystallinity. However, for bottle manufacture polyesters with low crystallinity are preferred for high transparency, thus increasing the susceptibility of PET to enzymatic attack. 

Maser and Rice, 1962, 1963) and renature very slowly. A conformational change of this type is known to affect structure. The product of the denaturation of EWC is EWG, known to be more susceptible to enzymatic attack. 

Table 6.1 Requirements for enzymatically resorbable polymers Preferable conditions for enzymatically resorbable polymers Presence of chemical bonds which are susceptible to enzymatic attack...

The biological nature of the fresh field latex makes it susceptible to enzymatic attack by bacteria and the latex is putrefied within hours of leaving the tree if not preserved. How soon it coagulates spontaneously depends on the ambient temperature and stability of the latex. The latex separates into lumps of rubber and a clear serum, followed by putrefaction and development of the characteristic bad odours. Any preservative for field NR latex to be effective against spontaneous coagulation and putrefaction should be able to destroy the microorganisms present, to aid in the stabilization of the latex and to act against the detrimental effect of heavy metal ions present in the field latex. Ideally the... 

Polyesteramides can be l drolytically degraded through ester bond cleavages [108]. The degradation process is clearly accelerated at high temperatures, or in acid or basic pH media In the same w, the polymer is susceptible to enzymatic attack with protease such as proteinase K. 

In vitro studies of LSD with purified calf thymus DNA showed that it might cause changes In the conformation of DNA and thus make It more susceptible to enzymatic attack and breakage. Glycolysis was observed to be significantly Increased In the rat brain. In a study of the effect of LSD on carbohydrate metabolism. 

Two other cases are related to compositional or structural heterogeneity. Often a protein sample isolated from an organism consists of a mixture of several enzymes. (Even some commercial enzyme samples contain several components.) Whereas the main enzyme component may carry out one set of reactions, the minor component(s) may have reactivity towards a different set of reactions. A similar situation arises when an enzyme exhibits multiple enzyme forms. Finally, unexpected enzymatic activity may be found when the polymer is heterogeneous. For example, a polymer may contains minor amounts of other materials, and an enzyme may react with the minor materials. A related situation occurs when the polymer contains a structural variation or a substructure that is susceptible to enzymatic attack. 

Examples of types of bonds that are susceptible to enzymatic attack... 

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