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

    hydride transfer, proton transfer, aromatic bimolecular nucleophilic addition, overall product formed, 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
    Aeropyrum pernix 1.1 1-Pentanol pH 8.0, 60°C
    Yokenella sp. 11 (2E)-but-2-en-1-ol pH 8.0, 55°C
    Sulfolobus acidocaldarius 8.4 NAD+ 65°C, pH 8.0
    Oenococcus oeni 4.9 NAD+ pH 9.0, 60°C, recombinant enzyme
    Thermus thermophilus 0.7 4-methoxybenzaldehyde pH 6.0, 65°C
  • Temperature
    Organism Temperature Range Comment
    Natronomonas pharaonis 50 - 80 50°C: 45% of maximal activity, 80°C: about 60% of maximal activity
    Candida parapsilosis 20 - 50 20°C: about 80% of maximal activity, 50°C: about 55% of maximal activity
    Magnusiomyces capitatus 20 - 50 20°C: about 80% of maximal activity, 50°C: about 60% of maximal activity, reduction of N-benzyl-3-pyrrolidinone
    Saccharomyces cerevisiae 15 - 50
    Sporotrichum pulverulentum 10 - 60 10°C: about 65% of maximal activity, 50°C: about 40% of maximal activity
  • pH
    Organism pH Range Comment
    Saccharomyces cerevisiae 5 - 9
    [Candida] maris 5.5 - 9 reduction reaction activity range, profile overview
    Geobacillus thermodenitrificans 6 - 9
    Equus caballus 7 - 11 under the analyzed conditions, the activity of HLADH steadily increases with increasing pH up to pH 9.0 and then decreases at more alkaline conditions, but highest oxidative lactimization activity at pH 11.00 in the coupled assay with NADH oxidase
    Homo sapiens 8 - 12 about 30% of maximal activity at pH 8.0 and at pH 12.0

Associated Proteins

Protein name Organism
Alcohol dehydrogenase, propanol-preferring Escherichia coli (strain K12)
Alcohol dehydrogenase-like 5 Mouse-ear cress
Alcohol dehydrogenase 4 Baker's yeast
NAD-dependent alcohol dehydrogenase Saccharolobus solfataricus (strain ATCC 35092 / DSM 1617 / JCM 11322 / P2)
Probable alcohol dehydrogenase Escherichia coli (strain K12)