Alcohol dehydrogenase reporter

A ruthenium complex [RuCl2(TPPTS)2]2 was used for regeneration of NADP+ to NADPH withhydrogen. Thus, 2-heptanonewas reduced with alcohol dehydrogenase from Thermoanaerobacter brockii in the presence of the mthenium complex, NAD P, and hydrogen at 60°C to (S)-2-heptanol in 40 % ee. Turnover number was reported to be 18 (Figure 8.6) [5cj. 

There have been a number of reports of electrocatalysis of alcohol oxidation using immobilized PQQ-dependent alcohol dehydrogenases or flavin-containing alcohol dehydrogenases or oxidases with dissolved mediators in solution. Co-immobihzing the mediator with the enzyme is advantageous, as set out in Section 17.1, and several such strategies have been employed for electrocatalytic alcohol oxidation. 

The inactivation of enzymes containing the zinc-thiolate moieties by peroxynitrite may initiate an important pathophysiological process. In 1995, Crow et al. [129] showed that peroxynitrite disrupts the zinc-thiolate center of yeast alcohol dehydrogenase with the rate constant of 3.9 + 1.3 x 1051 mol-1 s-1, yielding the zinc release and enzyme inactivation. Later on, it has been shown [130] that only one zinc atom from the two present in the alcohol dehydrogenase monomer is released in the reaction with peroxynitrite. Recently, Zou et al. [131] reported the same reaction of peroxynitrite with endothelial NO synthase, which is accompanied by the zinc release from the zinc-thiolate cluster and probably the formation of disulfide bonds between enzyme monomers. The destruction of zinc-thiolate cluster resulted in a decrease in NO synthesis and an increase in superoxide production. It has been proposed that such a process might be the mechanism of vascular disease development, which is enhanced by diabetes mellitus. 

In the following year, Cleland and his coworkers reported further and more emphatic examples of the phenomenon of exaltation of the a-secondary isotope effects in enzymic hydride-transfer reactions. The cases shown in Table 1 for their studies of yeast alcohol dehydrogenase and horse-liver alcohol dehydrogenase would have been expected on traditional grounds to show kinetic isotope effects between 1.00 and 1.13 but in fact values of 1.38 and 1.50 were found. Even more impressively, the oxidation of formate by NAD was expected to exhibit an isotope effect between 1.00 and 1/1.13 = 0.89 - an inverse isotope effect because NAD" was being converted to NADH. The observed value was 1.22, normal rather than inverse. Again the model of coupled motion, with a citation to Kurz and Frieden, was invoked to interpret the findings. 

A few years later, Cha, Murray and Klinman published a report on isotope effects in the redox interconversion of benzyl alcohol-benzaldehyde/NAD -NADH, with catalysis by yeast alcohol dehydrogenase. This article effected among biochemists... 

Two studies in Table 2 (entries 8 and 9) proceed from previous reports question of tunnehng in the action of horse-liver alcohol dehydrogenase. 

Asymmetric electroreduction of ketones to the corresponding chiral alcohols has recently been reported. Typical examples are the reduction of ketones bearing chiral auxiliaries [68, 69], and the indirect reduction of ketones with alcohol dehydrogenase (ADH), as a mediator (Scheme 32) [70]. 

Isotope effects have also been applied extensively to studies of NAD+/NADP+-linked dehydrogenases. We typically treat these enzymes as systems whose catalytic rates are limited by product release. Nonetheless, Palm clearly demonstrated a primary tritium kinetic isotope effect on lactate dehydrogenase catalysis, a finding that indicated that the hydride transfer step is rate-contributing. Plapp s laboratory later demonstrated that liver alcohol dehydrogenase has an intrinsic /ch//cd isotope effect of 5.2 with ethanol and an intrinsic /ch//cd isotope effect of 3-6-4.3 with benzyl alcohol. Moreover, Klin-man reported the following intrinsic isotope effects in the reduction of p-substituted benzaldehydes by yeast alcohol dehydrogenase kn/ko for p-Br-benzaldehyde = 3.5 kulki) for p-Cl-benzaldehyde = 3.3 kulk for p-H-benzaldehyde = 3.0 kulk for p-CHs-benzaldehyde = 5.4 and kn/ko for p-CHsO-benzaldehyde = 3.4. 

Mevaldate reductase [EC 1.1.1.32] catalyzes the reaction of (7 )-mevalonate with NAD to produce mevaldate and NADH. Mevaldate reductase (NADPH) [EC 1.1.1.33] catalyzes the reaction of (i )-mevalonate with NADP+ to produce mevaldate and NADPH. There are reports that this enzyme may be identical with alcohol dehydrogenase (NADP+) [EC 1.1.1.2]. 

A sequential enzyme-catalyzed reaction mechanism in which two substrates react to form two products and in which there is a preferred order in the binding of substrates and release of products. Several enzymes have been reported to have this type of binding mechanism, including alcohol dehydrogenase , carbamate kinase , lactate dehydrogenase , and ribitol dehydrogenase. ... 

The reduction of 3- and 4-thiepanones (41 and 42) was reported using either hydride (LAH) (67AG(E)872, 70JOC584) or horse liver alcohol dehydrogenase enzymes which gave the 3-hydroxy- (136) and 4-hydroxy- (43) thiepane in optically active form (81CJC1574. ... 

The reduction of ethyl trifluoroacetoacetate by bacterial alcohol dehydrogenases has been reported by Zhang et alP and the product used as an intermediate in the synthesis of Befloxatone as shown in Figure 1.42. 

Ingestion of methanol, particularly during the prohibition era, resulted in significant illness and mortality. Where epidemics of methanol poisoning have been reported, one-third of the exposed population recovered with no ill effects, one-third have severe visual loss or blindness, and one-third have died. Methanol itself is not responsible for the toxic effects but is rapidly metabolized in humans by alcohol dehydrogenase to formaldehyde, which is subsequently metabolized by aldehyde dehydrogenase to form... 

---