Quantity of enzyme adsorbed

Adsorption isotherms are an effective means to measure the quantity of enzyme adsorbed as a function of bulk concentration. In addition, the shape of the isotherm gives an indication of the affinity of the enzyme for the solid surface (1,2). By determining... 

Starch can be enzymically converted in the presence of pigment. The conversion follows a similar time-temperature cycle as in neat starch conversion. The pigment will adsorb a portion of the enzyme adsorption can be minimized by the addition of sodium silicate to the mixture prior to the addition of the enzyme (Vanderbilt process). Even with silicate treatment, a higher quantity of enzyme will be required to reach a specific viscosity target. Other coating components, such as latex and lubricants, have to be added after the conversion. The Vanderbilt process is now rarely used for the preparation of coating binder. 

To reconcile the results of Figures 1 and 2, assume that the number of molecules that participated in the reaction are rapidly obtained, or suppose that the quantities of enzyme that carry out the hydrolysis are insufficient compared with the quantities of adsorbed enzymes ( a). 

In the study of the law of enzyme actions, consideration must be taken of the fact that trypsin is adsorbed by a whole series of substances, and that the enzyme adsorbed may again become active in consequence of the phenomenon of autolysis. The quantity of active enzyme present in a digestive mixture not always being constant in all the phases of the reaction, it is evident that tmder such conditions we can no longer observe the proportionality of time and of the quantity of enzyme. Thus it is that the addition of charcoal powder to a solution of trypsin causes a very perceptible diminution of digestive power. The charcoal, previously kept in a colloidal liquid, such as a solution... 

Changes in the water transport rate of treated PET fabrics have been measured by a vertical wicking test in which the rising height of water in a strip of fabric is determined [3, 33, 77], Measurements of the dissipation of a drop of water on fabric [ 11, 38,62], liquid retention capacity (the ratio of the amount of liquid to the dry fabric quantity), and moisture regain (the amount of water a dry fiber absorbs from the air at a defined relative humidity) [43, 44, 51, 60] also aim to determine changes in the water absorption behavior of treated PET fabrics. Incomplete removal of enzymes adsorbed to the PET surface can, however, easily lead to incorrect results obtained using these methods [11, 23, 102]. 

Waste-treatment processes commonly result in the production of solid wastes that must be disposed of safely. Enzymatic treatment is no exception. For example, although enzymatic treatment may not produce as large a quantity of solid products as does biological treatment, some solid residues may be formed, e.g., the polymer precipitates formed during the treatment of phenols with peroxidases, spent adsorbents such as talc, chitin, or activated carbon that are used to eliminate the soluble products of enzymatic reactions, or residues of plant materials such as raw soybean hulls when they are used in place of purified enzymes during treatment. Perhaps, the polymers and adsorbents could be incinerated to recover some energy if the emission of dangerous combustion by-products can be controlled or prevented. The residues of plant materials could potentially be composted and used as soil conditioners, provided that pollutants do not leach from them at substantial rates. To date, none of these disposal problems have been addressed adequately. 

For practical applications, essentially irreversible adsorption is required to prevent leaching, or desorption, which leads to activity loss. Optimum conditions are determined empirically, by varying pH, temperature, ionic strength, and quantities of protein and adsorbent. Desorption of enzymes may also be substrate induced, where high substrate concentrations cause leaching due to conformational changes. 

The evolution of the enzyme adsorption was studied with tritiated molecules at pH 2-11 (Figure 5). Even for a low adsorption of enzyme molecules, maximum activity can be obtained. Thus, either the molecules initially adsorbed contribute to the kinetics, or the enzyme required for activity is not permanently adsorbed. If it were, the small quantities would be immeasurable with our techniques and indistinguishable from the ordinary adsorption or film penetration. 

The results of investigations of enzymatic activity in the immobilized state. When laccase, peroxidase, and other enzymes are adsorbed on dispersive electroconductive carriers, their enzymatic activity perceptibly declines, thus indicating a denaturing of part of the macromolecules. In this case, however, there is a sufficient quantity of denatured enzyme molecules strongly bonded with the carrier, which display a specific biocatalytic activity in model reactions of the substrates. It is these molecules of the enzyme, as will be seen further, that are responsible also for the electrocatalytic activity of the system. 

For this reason yeast invertase preparations contain little if any of this enzyme, and to obtain it very mild autolysis conditions must be employed. Dried yeasts seem to be a particularly good source 66). Such preparations contain considerable quantities of invertase, but if the low-temperature autolysate is treated with limited portions of activated aluminum hydroxide, the a-glucosidase is preferentially adsorbed and then may be eluted with solutions of secondary phosphates 66). 

For the reaction to occur A and B must collide in the correct orientation so that orbital electrons can reposition to enable product formation. The closer the reactant molecules are the greater the chance of a collision, i.e. high concentrations of reactants augment the reaction. Enzymes promote the reaction by adsorbing the reactants on to a polypeptide chain in close proximity and proper orientation which results in an effective concentration of the reactants frequently present intracellu-larly in minute quantities. 

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