Dissolves readily at 5 mg/ml in 0,01 M Sodium Phosphate pH 7,5 to give a clear colourless solution.
- One unit will convert 1,0 µmole of NAD/min at 25 °C
Yeast ADH which has a more narrow specificity than that of liver enzyme, accepts ethanol, is somewhat active on the straight chain primary alcohols, and acts to a very limited extent on certain secondary and branched chain alcohols. NADP does not serve as coenzyme.
Activators: Sulphyhydryl activating reagents, mercaptoethanol, dithiothreitol, cysteine, etc., and heavy metal chelating reagents.
Inhibitors: Heavy metals and -SH reagents.
Stabilizers: Dilute solution of the enzyme may be stabilized by serum albumin, gelatin, and/or glutathione or cysteine At pH values below 6,0 and above 8,5 the enzyme is increasingly unstable. More concentrated solutions of the enzyme in high purity water, near neutrality, are stable several days at 5 °C.
Alcohol dehydrogenases are a group of dehydrogenase enzymes that occur in many organisms. It is a metalloenzyme containing four tightly bound zinc atoms per molecule. Each subunit also contains a second zinc atom (conformational zinc), which stabilises the enzyme′s tertiary structure. Per subunit, there are two distinct active site Sulphydryl groups which can be distinguished on the basis of differential reactivity with iodoacetate and butyl isocyanate. A histidine residue is considered to have an essential role.
Alcohol dehydrogenase catalyses 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.
Yeast alcohol dehydrogenase (yADH) serves as an excellent model system for enzyme-catalysed H transfer because unlike many other enzymes, the chemical step, oxidation of a primary alcohol to an aldehyde by NAD+, is rate-limiting with aromatic substrates.