Alcohol, tests dehydrogenase

Levels of a number of metabolites as well as a number of enzymes in body fluids are indicative of disease conditions. Many of the enzymatic reactions mentioned above have been used in solution clinical assays as well as in test strips.446,497-508 512-515 Assays for hydrogen peroxide and the enzyme peroxidase using NADH and a tetrazolium salt have been de-scribed.509,5io Assays of exogenous substances (e.g., drugs or their metabolites) also utilize this chemistry. The determination of alcohol using alcohol dehydrogenase is an example.511 As mentioned above, the assay of enzyme levels can also be achieved using tetrazolium salts.516-520... 

The work in the biosensor industry permitted the testing and proved of stability and reproducibility of enzymes, within the conditions employed in that area. Enzymes with demonstrated stability include lactate oxidase, malate dehydrogenase, alcohol oxidase, and glutamate oxidase. 

Fig. 6 Illustration from Chin and Klinman. Increased catalytic activity of horse-liver alcohol dehydrogenase in the oxidation of benzyl alcohol to benzaldehyde by NAD, measured by cat/ M (ordinate), correlates with the Swain-Schaad exponent for the -secondary isotope effect (abscissa), for which values above about four are indicators of tunneling. This is a direct test of the hypothesis that tunneling in the action of this enzyme contributes to catalysis. As the rate increases by over two orders of magnitude and then levels off, the anomalous Swain-Schaad exponents also increase and then level off. Reproduced from Ref. 28 with the permission of the American Chemical Society.

To test the hypothesis that the conformational flexibility of the thermophilic enzyme is lower at room temperature than at higher temperatures, Kohen and Klinman measured, by FTIR, the time course of H/D exchange of protein N-H sites in deuterium oxide for the thermophilic alcohol dehydrogenase. Their measurements were made at the optimal host-organism temperature of 65 °C and at 25 °C, below the transition temperature. They also included yeast alcohol dehydrogenase at 25 °C, which is the optimal temperature for its own host organism. 

Ethanol oxidation, via alcohol dehydrogenase, reduces testosterone secretion, due to a high NADH/NAD ratio is the Leydig cells in the testes. 

Lactobacillus brevis whole-cell biotransformation When the reduction of diketo ester la was performed with whole cells of Lactobacillus brevis or L. kefir, formation of the 3,5-dihydroxy ester (3R,5S)-5a was observed [10, 22]. This was surprising since it is known that the prevailing alcohol dehydrogenase in I. brevis is the one described as LBADH [23] and since, moreover, this enzyme does not reduce P-keto 5-hydroxy ester 2a to the corresponding dihydroxy ester (Scheme 2.2.7.6). Under the conditions tested, further alcohol dehydrogenase activity is clearly present in I. brevis and I. kefir. Pfruender et al. optimized the production of L. kefir cells and used this biocatalyst for the one-pot synthesis of dihydroxy ester syn-(3R,5S)-5a using diketo ester la as starting material [24]. 

Different purified or partially purified enzymes were tested successfully, such as horse liver dehydrogenase [3], Sulfolobus solfataricus dehydrogenase [4], Pischia pastoris alcohol oxidase [5, 6], the baker s yeast alcohol dehydrogenase [7], and finally lipolytic enzymes, which probably constitute the major part of the work devoted to the use of enzymes working at the solid/gas interface, as summarized in a recent publication [8]. 

Fig. 7. Diagrams of the schemes for modifying levels of A, alcohol dehydrogenase and B, pyruvate decarboxylase activity and testing for survival of anoxia. In A, constructs contain the 35S promoter of the cauliflower mosaic virus (35S) driving expression of the cotton Adh cDNA in either the sense (Adh) or antisense (hdA) orientation, linked to the 3 termination signal of the nopaline synthase gene (Nos). Alternatively, the expression of cotton Adh cDNA is under control of the pea Adh promoter sequence (pea Adh). In B, either the 35S promoter or the pea Adh promoter is used to drive expression of the maize pyruvate decarboxylase cDNA (Pdc), linked to a Nos 3 termination sequence. Constructs are introduced into cotton via Agrobacterium tumefaciens-mediated infection of cotton. Transformed cotton callus is then assayed for its ability to survive anoxia.

Recombinant strains of Acetobacter aceti, cloned with either alcohol dehydrogenase or aldehyde dehydrogenase, have been tested for vinegar production. The bacteria with the aldehyde dehydrogenase gene produced acetic acid more rapidly than those with the alcohol dehydrogenase, and were more resistant to high concentrations of acetic acid. 

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