Alcohol dehydrogenases (ADH) (EC 1.1.1.1) are a group of dehydrogenase enzymes that occur in many organisms and facilitate the interconversion between alcohols and aldehydes or ketones with the reduction of nicotinamide adenine dinucleotide (NAD+) to NADH. In humans and many other animals, they serve to break down alcohols that otherwise are toxic, and they also participate in generation of useful aldehyde, ketone, or alcohol groups during biosynthesis of various metabolites. In yeast, plants, and many bacteria, some alcohol dehydrogenases catalyze the opposite reaction as part of fermentation to ensure a constant supply of NAD+.
The alcohol dehydrogenases comprise a group of several isozymes that catalyse the oxidation of primary and secondary alcohols to aldehydes and ketones, respectively, and also can catalyse the reverse reaction.In mammals this is a redox (reduction/oxidation) reaction involving the coenzyme nicotinamide adenine dinucleotide (NAD+).
In biotransformation, alcohol dehydrogenases are often used for the synthesis of enantiomerically pure stereoisomers of chiral alcohols.Often, high chemo- and enantioselectivity can be achieved. In fuel cells, alcohol dehydrogenases can be used to catalyze the breakdown of fuel for an ethanol fuel cell.
Off-white lyophilized powder, soluble in water, pI 5.4, optimum pH 8.6-9.0 (ethanol oxidation) or 7.0 (aldehyde reduction). Stability: high concentration of nearly neutral enzyme in pure water can be stable for several days at 5℃, unstable in acidic (pH lower than 6.0) and alkaline (pH greater than 8.5) solution; adding glutathione, cysteine or serum albumin to dilute solution can increase its stability; lyophilized powder containing sucrose and phosphate, stored at 4℃ for six months, the vitality is reduced by 10%; crystal suspension containing phosphate, stored at 4℃ for six months, the vitality is reduced by 40%. Crystallized suspension containing phosphate, 40% reduction in viability for six months at 4°C. Activators include mercaptoethanol, dimercaptosuccinol, cysteine and heavy metal chelators; inhibitors include heavy metals and sulfhydryl reagents. Enzymatic reaction: alcohol + coenzyme I ═ aldehyde or ketone + reduced coenzyme I.
Alcohol dehydrogenase catalyzes the reaction: RCH2OH +NAD+ RCHO + NADH + H+ It facilitates the interconversion between alcohols and aldehydes or ketones with the reduction of nicotinamide adenine dinucleotide (NAD+ to NADH). In biotransformation, alcohol dehydrogenases are often used for the synthesis of enantiomerically pure stereoisomers of chiral alcohols.
This product has been enhanced for energy efficiency and waste prevention when used in fuel cell research.
Alcohol dehydrogenase catalyzes the oxidative conversion of alcohol into aldehyde. It has a homodimeric structure with a co-enzyme binding domain at the C-terminal and an N-terminal catalytic domain. The active site is located at the interdomain cleft. Binding of NAD+ in the active site causes conformational changes which create the binding site for the alcohol substrate.
