Enzyme amount

Worldwide consumption of industrial enzymes amounted to approximately 720 million in 1990 about one-third was accounted for by the U.S. market. Estimation of worldwide consumption is difficult because official production figures are scarce. A relatively large portion of the production of starch-processing enzymes is for internal consumption. Furthermore, the currency used for the estimation also influences the result considerably. 

The first assumption had been that there were two mechanisms involved in the degradation process. (Fig. 3) TTie first one was very fast (rate constant kj) affecting the peripheric part of the parenchyma (Mj) where most of the enzyme was initialy adsorbed. The second mechanism was slow (rate constant k2) for it affected the deeper zone of the tissue (M2) where the enzyme amount was low. 

Statistical analysis of enzyme amounts could be used to demonstrate which enzyme plays an important role in the decolourization process of azo dyes, and it was reported that the complete decolourization time and enzyme activity are negatively correlative [47]. 

Chemical reactions enhanced by catalysts or enzymes are an integral part of the manufacturing processes for the majority of chemical products. The total market for catalysts and enzymes amounts to 11.5 billion (2005), of which catalysts account for about 80%. It consists of four main applications environment (e.g., automotive catalysts), 31% polymers (e.g., polyethylene and polypropylene), 24% petroleum processing (e.g., cracking and reforming), 23% and chemicals, 22%. Within the latter, particularly the catalysts and enzymes for chiral synthesis are noteworthy. Within catalysts, BINAPs [i.e., derivatives of 2,2 -bis(diphenylphosphino) -1, l -bis-l,l -binaphthyl) have made a great foray into chiral synthesis. Within enzymes, apart from bread-and-butter products, like lipases, nitrilases, acylases, lactamases, and esterases, there are products tailored for specific processes. These specialty enzymes improve the volumetric productivity 100-fold and more. Fine-chemical companies, which have an important captive use of enzymes, are offering them to third parties. Two examples are described here ... 

However, enzyme deactivation is still observed under these conditions, as is clearly demonstrated in Figure 6.6, which shows a so-called Selwyn test [26]. In this set-up, ISOOmM AA and 600 mM ClAA were allowed to react with various amounts of DERA under identical conditions. According to Selwyn s theory on enzyme inactivation, plotting eot, in which Sq represents the initial total enzyme amount and t the reaction time, against the concentration of the product p, progress curves should be superimposable provided no inactivation occurs. If not, the assumption that the rate of product formation is proportional to the initial total enzyme amount does not hold true, which could point at enzyme deactivation. 

Many of the enzymes participating in de novo synthesis of deoxyribonucleotide triphosphates, as well as those responsible for interconversion of deoxyribonucleotides, increase in activity when cells prepare for DNA synthesis. The need for increased DNA synthesis occurs under three circumstances (1) when the cell proceeds from the G0, or resting, stage of the cell cycle to the S, or synthetic or replication, stage (fig. 23.26) (2) when it performs repair after extensive DNA damage and (3) after infection of quiescent cells with virus. When cells leave G0, for example, enzymes such as thymidylate synthase and ribonucleotide reductase, increase as well as the corresponding mRNAs. These increases in enzyme amount supplement allosteric controls that increase the activity of each enzyme molecule. Corresponding decreases in amounts of these enzymes and their mRNAs occur when DNA synthesis is completed. 

Regarding the enzyme polymer ratio, high polymer amounts may provide higher immobilisation yields but may restrict the enzyme flexibility and functionality, and high enzyme amounts may provide higher responses but may limit the sensitivity of the biosensor. The dilemma has appeared and the choice will depend on the own particular interests. The 1 2 ratio provided higher absorbance values (0.259 coefficient of variation (CV) — 17%) than those obtained with the 2 1 (0.041 CY — 9%) and the 1 3 (0.189 CV = 15%) ratios. In the same way, the 1 2 ratio also provided the highest immobilisation yields after 30-min incubation in buffer (62% as compared to 16% and 41% for the 2 1 and the 1 3 ratios, respectively). In our case, the results clearly demonstrate that the 1 2 enzyme polymer ratio is the optimum one for the biosensor construction. 

Figure 8.4 shows the influence of e on the x (r) shape. For fixed (k, A), we simulated the time courses for e = 0.5, 1, 2, 5. It is noted that the shape of the substrate profiles varies remarkably with the values of e thus profiles of biphasic, power-law, and nonlinear type are observed. So, the sensitivity of the kinetic profile regarding the available substrate and enzyme amounts is studied by using several e values for low substrate or high enzyme amounts the process behaves according to two decaying convex phases, in the reverse situation the kinetic profile is concave, revealing nonlinear behavior. 

From the conservation law of enzyme sites, e = eo — c, the enzyme population size can be substituted by the previous relation involving the initial enzyme amount eo and the current complex population size c. The intensity functions become... 

Shieh et al. (2003) indicated a biodiesel transesterification using soybean oil and methanol and commercial immobilized lipase from R. miehei (Lipozyme IM-77). The response surface analysis showed that the following variables were important reaction time, temperature, enzyme amount, molar ratio of methanol to soybean oil, and added water content on percentage weight conversion to soybean oil methyl ester by transesterification. The optimum yield based on ridge max analysis gave a 92.2% weight conversion. 

A five-level-five-factor CCRD was employed in this study, requiring 32 experiments (Cochran and Cox, 1992). The fractional factorial design consisted of 16 factorial points, 10 axial points (two axial points on the axis of each design variable at a distance of 2 from the design center), and 6 center points. The variables and their levels selected for the study of biodiesel synthesis were reaction time (4-20 h) temperature (25-65 °C) enzyme amount (10%-50% weight of canola oil, 0.1-0.5g) substrate molar ratio (2 1—5 1 methanol canola oil) and amount of added water (0-20%, by weight of canola oil). Table 9.5 shows the independent factors (X,), levels and experimental design coded and uncoded. Thirty-two runs were performed in a totally random order. 

The effect of varying reaction temperature and substrate molar ratio at constant reaction time (12h), enzyme amount (30%), and added water content (10%) is shown in Figure 9.1. In general, an increase in substrate molar ratio led to lower yields at any temperature. It was concluded that a great deal of methanol inactivated Novozym 435 to synthesize the biodiesel. Similar results, that an excess of methanol decreased the enzymatic biodiesel catalyzed by Lipozyme IM77, was reported by our previous study (Shieh et al., 2003). 

The entire relationships between reaction factors and response can be better understood by examining the planned series of contour plots (Fig. 9.2) generated from the predicted model (equation 2) by holding constant the enzyme amount (20, 30, and 40%, weight of canola oil) and substrate molar... 

The optimum synthesis of enzymatic biodiesel was determined by the ridge max analysis (SAS, 1990). The method of ridge analysis computes the estimated ridge of maximum response for increasing radii from the center of original design. The ridge max analysis (Table 9.6) indicated that maximum molar conversion was 99.4 4.6% at 12.4h, 38.0°C, 42.3% enzyme amount, 3.5 1 substrate molar ratio, and 7.2% added water content at the distance of the coded radius 0.8. 

With dermatan sulfate, biosynthesis of the L-iduronic acid residue poses another problem. Incorporation of D-glucose-6-C into rat skin indicated that L-iduronic acid is derived from D-glucose without scission of the carbon chain (R7). A sulfotransferase has been isolated from rabbit skin (D4) which is specific for sulfation of a chemically desul-fated dermatan sulfate. However, the degree of sulfation achieved by this enzyme amounted to only one sulfate group per five or six disaccharide units. 

Enzyme Assays Activities of thymidylate synthase (Rode et al. 1990), thymidine kinase (Tsukamoto et al. 1991) and dihydrofolate reductase (Mathews et al. 1963) were assayed according to previously published procedures. dUTP-ase activity was determined by coupling with the thymidylate synthase-catalyzed reaction and measuring tritium released from [ H]dUMP (Golos and Rode 1999). The activity unit was defined as the enzyme amount required to convert 1 pmol of substrate per 1 min at 37°C. 

Enzyme Amount of bound enzyme, mg g dry carrier Residual activity (%) pH optimum t(°C) Optimum m[M]... 

Figure 2. Dependence of the rate of peroxidase oxidation of phenol on the start concentration of the substrate 1. catalase in solution C = 1,36x 10" M 2. catalase inunobilized on NORIT , enzyme amount g = 0,37 mg. Concentration of H2O2 C= 2x10 M Citrate buffer pH = 3.02...

Figure 4. Relationship InA - t for peroxidase oxidation riienoi by catalase immobilized on NORIT soot. Enzyme amount g = 0.41 mg., temperature 30 °C Citrate buffer pH = 3.02.

Between US 12 and 15 billion per year is spent worldwide for analytical purposes the portion used for enzymes amounts to about 50 million. Enzymes are being employed in clinical chemistry, the food and cosmetic industries, and biotechnology for the routine analysis of about 80 different substances, mainly low-molecular weight metabolites but also effectors, inhibitors, and the activity of enzymes themselves. 

Batch no. Amount o/2 Cone. o/2 Buffer amount Enzyme amount (% with respect to 2) Time Conversion (%) % ee of (S)-3... 

Amounts of neutral sugars and galacturonides released from apple AIS by pure enzymes. Amounts expressed in % of original amounts present, corrected for control. 

Overall enzyme amount in the reactor, M Number of capillary membranes in a bundle Product concentration, M L 3 Peclet number... 

Figure 7.21 Hydrolysis of 1.5 mM sucrose by cogelled invertase in an immobilized enzyme membrane reactor (IEMR). Comparison between experimental data in terms of glucose outlet concentration (Cp) vs. reaction time (t) and theoretical predictions (-). Enzyme amount, 0.398 x 10 s g/cm2 reaction temperature, 30°C pH 4.65 flow rate 1.13 x 103 ml/s.30...

Two commercials enzymes, Celluclast 1.5-L and Novozyme 188 (Sigma, St Louis, MO, USA), were used for enzymatic hydrolysis. Celluclast 1.5-L contained 98.2 FPU/ml of total cellulase P-glucosidase activity of Novozyme-188 was 540 unit/ml. One FPU is defined as the enzyme amount that releases 1 p.mol of glucose equivalents from Whatman no. 1 filter paper in 1 min. One unit of 3-glucosidase activity is defined as the enzyme amount that converts 1 imol of cellubiose to 2 pmol of glucose in 1 min [17],... 

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