Immobilized coenzymes

Lowe, C.R. (1979) Immobilized nucleotides and coenzymes for affinity chromatography. Pure Appl. Chem. 51,1429-1441. 

Many enzymes require the participation of dissociable coenzymes such as NAD+, NADP+ or ATP for their catalytic activities. The use of coenzymes to activate immobilized enzymes on a large scale is hampered by their relatively low stability and high cost. Attempts are therefore being made to stabilize the coenzymes and to find suitable means for their continuous regeneration. The principal approach has been to covalently attach a co-enzyme to a polymeric water-soluble matrix, thus making the co-enzyme, like the enzyme, potentially reusable (9,10). 

R. S. Phadke, Immobilization of enzymes/coenzymes for molecular electronics applications, BioSystems, 35, 179-182 (1995). 

K. F. Gu and T. M. S. Chang, Conversion of ammonia or urea into essential amino acids, using artificial cells containing an immobilized multienzyme system and dextran-NAD+ 2. Yeast alcohol dehydrogenase for coenzyme recycling, Biotechnol. Appl. Biochem., 12, 227-236 (1990). 

O. Miyawaki and T. Yano, Dynamic affinity between dissociable coenzyme and immobilized enzyme in an affinity chromatographic reactor with single enzyme, Biotechnol. Bioeng., 39, 314-319 (1992). 

NAD glycohydrolases from rat liver nuclei, 66, 151 poly(ADP-ribose) synthetase from rat liver nuclei, 66, 154 poly(ADP-ribose) synthetase from calf thymus, 66, 159 extraction and quantitative determination of larger than tetrameric endogenous polyadenosine diphosphoribose from animal tissues, 66, 165 covalent modification of proteins by metabolites of NAD, 66, 168 coenzyme activity of NAD bound to polymer supports through the adenine moiety, 66, 176 use of differently immobilized nucleotides for binding NAD -dependent dehydrogenases, 66, 192. 

Biosensors constructed for ethanol and D-glucose measurements in beverages were built using ferrocene compounds as electron transfer mediators between the coenzyme PQQ of immobilized enzymes glucose (GDH) and alcohol (ADH) dehydrogenases and a carbon electrode surface <2003JOM(668)83>. 

Immobilized Derivatives of Cobalamins and Their Use as Affinity Adsorbents for a Study of Enzyme-Coenzyme Interaction... 

Figure 16.12 Release of immobilized insulin in respond to addition of glucose. The disulfide bond is cleaved by electrons resulting from glucose transformation to gluconic acid by glucose oxidase. This approach requires a coenzyme flavin adenine dinucleotide (FAD)...

Finally, if enzymes can be stabilized in the presence of organic solvents by immobilization, an area that appears especially promising is the synthesis of organic flavor compounds. This is likely to require regeneration of expensive cosubstrates, such as the nicotinamide coenzymes, and such processes remain to be optimized. However, the stereospecificity of enzyme-catalyzed reactions and the high... 

Further improvement of this process can be reached by immobilization of the enzymes in an EMR. The coenzyme can be enlarged chemically by binding it to polyethyleneglycol (PEG) in order to prevent leakage of the coenzyme through the membrane. This LeuDH catalyzed synthesis of enantiomerically pure L-Tle runs now routinely on a multiton scale at Degussa [154]. 

Several sensors for L-alanine are obtained by immobilizing L-alanine dehydrogenase over an ammonia gas-sensing electrode (288) or over an O2 sensor (280). The enzyme catalyzes the specific deamination of alanine in the presence of the coenzyme NAD ... 

The original interest in avidin was because of the egg white injury that was subsequently shown to be avidin-induced biotin deficiency. Thereafter, avidin was used because of its high affinity for biotin (a dissociation constant of 10 mol per L), not only to induce experimental biotin deficiency, but also to bind to biotin in isolated enzymes and thus, by irreversible inhibition, demonstrate the coenzyme role of biotin. Because of the stability of the avidin-biotin complex, it has not been possible to use immobilized avidin as a means of purifying biotin enzymes - there seems to be no way in which the enzyme can be released from avidin binding. Because of its high affinity for biotin, avidin is used to provide an extremely sensitive system for linking reporter molecules in a variety of analytical systems. 

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