<p>Alcohol dehydrogenase (<db_xref db="EC" dbkey="1.1.1.1"/>) (ADH) catalyzes the reversible oxidation of ethanol to acetaldehyde with the concomitant reduction of NAD. Currently three, structurally and catalytically, different types of alcohol dehydrogenases are known:<ul><li>Zinc-containing 'long-chain' alcohol dehydrogenases.</li><li>Insect-type, or 'short-chain' alcohol dehydrogenases.</li><li>Iron-containing alcohol dehydrogenases.</li></ul> </p><p>Iron-containing ADH's have been found in yeast (gene ADH4) [<cite idref="PUB00002060"/>], as well as in <taxon tax_id="542">Zymomonas mobilis</taxon> (gene adhB) [<cite idref="PUB00003722"/>]. These two iron-containing ADH's are closely related to the following enzymes:<ul><li> <taxon tax_id="562">Escherichia coli</taxon> propanediol oxidoreductase (<db_xref db="EC" dbkey="1.1.1.77"/>) (gene fucO) [<cite idref="PUB00002085"/>], an enzyme involved in the metabolism of fucose and which also seems to contain ferrous ion(s).</li><li> <taxon tax_id="1488">Clostridium acetobutylicum</taxon> NADPH- and NADH-dependent butanol dehydrogenases (<db_xref db="EC" dbkey="1.1.1"/>) (genes adh1, bdhA and bdhB) [<cite idref="PUB00002203"/>], an enzyme which has activity using butanol and ethanol as substrates.</li><li> E. coli adhE [<cite idref="PUB00001606"/>], an iron-dependent enzyme which harbor three different activities: alcohol dehydrogenase, acetaldehyde dehydrogenase (acetylating) (<db_xref db="EC" dbkey="1.2.1.10"/>) and pyruvate-formate-lyase deactivase.</li><li>Bacterial glycerol dehydrogenase (<db_xref db="EC" dbkey="1.1.1.6"/>) (gene gldA or dhaD) [<cite idref="PUB00002240"/>].</li><li> <taxon tax_id="1534">Clostridium kluyveri</taxon> NAD-dependent 4-hydroxybutyrate dehydrogenase (4hbd) (<db_xref db="EC" dbkey="1.1.1.61"/>).</li><li> <taxon tax_id="546">Citrobacter freundii</taxon> and <taxon tax_id="573">Klebsiella pneumoniae</taxon> 1,3-propanediol dehydrogenase (<db_xref db="EC" dbkey="1.1.1.202"/>) (gene dhaT).</li><li> <taxon tax_id="1471">Bacillus methanolicus</taxon> NAD-dependent methanol dehydrogenase (<db_xref db="EC" dbkey="1.1.1.244"/>) [<cite idref="PUB00002196"/>].</li><li>E. coli and <taxon tax_id="602">Salmonella typhimurium</taxon> ethanolamine utilization protein eutG.</li><li>E. coli hypothetical protein yiaY.</li></ul></p> Alcohol dehydrogenase, iron-type