Enzyme - Alcohol dehydrogenase

Alternative Name(s)
  • Aldehyde reductase.

Catalytic Activity

primary alcohol + NAD(+) = an aldehyde + H(+) + NADH


Zn(2+) or Fe cation.

Reaction Mechanisms

    An NAD+-dependent enzyme that catalyzes the oxidation of alcohols to aldehydes/ketones and that is also able to further oxidize aldehydes to their corresponding carboxylic acids. It is a zinc-independent protein which is a member of the short-chain dehydrogenases/reductases (SDR) family. It is known to be inhibited by 2,2,2-trifluoroethanol and pyrazole.

    The NAD cofactor binds first, causing one of the active site waters to deprotonate Tyr152. Once the alcohol substrate has been bound, Tyr152 abstracts its hydroxyl proton, initiating the hydride transfer to NAD. The ketone product is released first, followed by the NADH.
    Catalytic Residues
    AA Uniprot Uniprot Resid PDB PDB Resid
    Ser P00334 140 1mg5 139
    Tyr P00334 153 1mg5 152
    Lys P00334 157 1mg5 156
    Asn P00334 109 1mg5 108
    Step Components

    overall product formed, aromatic bimolecular nucleophilic addition, proton transfer, hydride transfer, cofactor used

    Step 1.

    Binding of the NAD initiates the deprotonation of Tyr152.

    Step 2.

    Tyr152 abstracts a proton from the substrate alcohol, initiating the elimination of a hydride (which is added to NAD).


    The products of the reaction.

Reaction Parameters

  • Kinetic Parameters
    Organism KM Value [mM] Substrate Comment
    Sphingomonas sp. A1 0.000015 D-sorbitol at pH 7.9 and 25°C
    Citrobacter sp. S-77 0.007 ethanol pH 7.0, 30°C
    Oenococcus oeni 0.01 1,2-propanediol pH 8.0, 60°C, recombinant enzyme
    Aeropyrum pernix 0.017 ethanol pH 8.0, 60°C
    Saccharomyces cerevisiae 0.018 propanal pH 7.0, 30°C
  • Temperature
    Organism Temperature Range Comment
    Flavobacterium frigidimaris 0 - 60 0°C: about 70% of maximal activity, about 45% of maximal activity
    Sporotrichum pulverulentum 10 - 60 10°C: about 65% of maximal activity, 50°C: about 40% of maximal activity
    Brassica napus 10 - 45 activity increases from 10°C to 45°C
    Oenococcus oeni 10 - 80 more than 40% of activity between 40°C and 70°C with all substrates. The enzyme is not capable of reducing acetaldehyde at 80°C, while remaining activity for alcohol oxidation, temperature optimum lies between 50°C to 60°C
    [Candida] maris 10 - 75 activity range, profile overview
  • pH
    Organism pH Range Comment
    Thermoplasma acidophilum 2 - 8
    Methylorubrum extorquens 4 - 8 pH 4.0: about 35% of maximal activity, pH 8.0: about 70% of maximal activity
    [Candida] maris 4 - 8.5 oxidation reaction activity range, profile overview
    Candida parapsilosis 4 - 7.5 pH 4.0: about 80% of maximal activity, pH 7.5: about 60% of maximal activity
    Sulfolobus acidocaldarius 4.9 - 5.8 pH 4.9: about 25% of maximal activity, pH 5.8: about 40% of maximal activity, reduction reaction

Associated Proteins

Protein name Organism
Alcohol dehydrogenase-like 4 Mouse-ear cress
Alcohol dehydrogenase 3, mitochondrial Baker's yeast
Alcohol dehydrogenase E chain Horse
Alcohol dehydrogenase 1A Human
Alcohol dehydrogenase-like 3 Mouse-ear cress