Recycling enzymes

Salvi e enzymes recycle normally about 90% of these purines, and 10% are converted to tuic acid and excreted in urine. When purine catabcdism is increased significantly, a person is at risk for developing hyperuricemia and potentialty gout. 

L-Iactate is oxidized by lactate oxidase to pyruvate, which is reduced back to lactate by LDH. The total enthalpy change for this system can be further increased by addition of catalase, which makes the overall enthalpy change as large as -225 kJ/mol, so signal increases greater than 1000-fold can be obtained as a result. Co-enzyme recycling was also used for the determinations of ATP/ADP [161] and NAD(H) [162],... 

Microtiter Plate Technique for the Measurement of Glutathione in Fresh and Cryopreserved Lymphoblasts Using the Enzyme Recycling Method... 

A number of methods are available for the measurement of intracellular glutathione. Owen and Belcher first described the enzyme recycling method in 1965 (6). This was subsequently modified by Tietze in 1969 (7) and by Anderson in 1985 (8). Vandeputte et al. 1994 (9) adapted the assay for use in microtiter plates. It provides a sensitive and specific assay for the measurement of total intracellular glutathione, i.e., both GSH and GSSG. 

The enzyme recycling assay is particularly valuable in the study of stored cells because total reduced and oxidized glutathione is measured and therefore alterations in the intracellular ratio of reduced and oxidized glutathione that... 

Glutathione Measurement Using Enzyme Recycling Method 85... 

The plate is placed in the plate reader and the enzyme recycling reaction initiated by the addition of glutathione reductase, 40 pL to each well, again using a multichannel pipet. Care should be taken to ensure that there are no bubbles in the wells. 

The enzyme recycling assay is very sensitive to differences in the ionic strength of this buffer (13). Therefore, sufficient stock buffer should be prepared for all... 

Processes for the bioproduction of ethanol from cellulosic materials have been studied extensively. Some of the process steps are specialized and beyond the scope of this chapter. However, there are many recent review articles dealing with some specific subjects. Basically, the processes consist of a number of steps. They are availability and collection of raw feedstock [20], size reduction, pretreatment, fractionation of biomass components, enzyme production [21, 22], saccharification, enzyme recycle [23, 24], pentose fermentation, improvement of pentose-fermenting biocatalyst, overcoming of product inhibition, overcoming inhibition by substrate-derived inhibitors, ethanol recovery [25], steam generation and recycling [26], waste treatment, and by-product utilization. 

The cost of enzyme preparations has been decreasing in recent years however, it continues to affect considerably the price of ethanol obtained from cellulosic raw materials. Increased enzymatic hydrolysis efficiency is one way to reduce the enz)me cost in bioethanol production. Another method is enzyme recycle and reuse. Immobilization of biocatalysts allows for their economic reuse and development of continuous bioprocess. Although immobilization poses problems of substrate accessibility and binding for most endo- and exocellulases, P-glucosidase exhibits characteristics amenable to immobilization, such as activity on soluble substrates and the lack of a carbohydrate-binding module. Among the possible approaches, immobilization of (J-glucosidase is one prospective solution to the problem. 

In a mixture of SBO, methanol, and water, a lipase can carry out the transesterification reaction at high yields. The end product is similar to methyl soyate, except for the added aza-carboxylate ester. Since methanol is in excess, dimethyl esters are formed. The reaction can be conducted at a low temperature (35°C). Several lipases have been attempted, and the reaction is relatively straightforward. The use of an immobilized lipase (e.g., Novozym 435) is particularly beneficial because it allows enzyme recycling and cost reduction. 

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