Under fermentative conditions, catalyzes the sequential NADH-dependent reduction of acetyl-CoA to acetaldehyde and then to ethanol (PubMed:6752127, PubMed:2015910, PubMed:10612730, PubMed:10922373, PubMed:17280641). Under aerobic conditions, despite the reversibility of the two NADH-coupled reactions, wild-type E.coli cannot grow on ethanol as the sole carbon and energy source due to the down-regulation of adhE transcription and the inactivation of the enzyme by metal-catalyzed oxidation (MCO) (PubMed:10922373). Nevertheless, in the presence of oxygen, AdhE may act as a hydrogen peroxide scavenger and have a protective role against oxidative stress (PubMed:12783863). acetaldehyde + CoA + NAD(+) = acetyl-CoA + H(+) + NADH ethanol + NAD(+) = acetaldehyde + H(+) + NADH a primary alcohol + NAD(+) = an aldehyde + H(+) + NADH Formation of filaments, called spirosomes, is critical for activity (PubMed:31586059, PubMed:32188856, PubMed:32523125). Filamentation is essential for substrate channeling between the ALDH and ADH domains and efficient coupling of the ALDH and ADH enzymatic activities, and for the regulation of enzyme activity (PubMed:32188856, PubMed:32523125). In the absence of ligands, the spirosomes are compact (PubMed:31586059, PubMed:32188856, PubMed:32523125). Binding of NAD(+) and Fe(2+) cofactors induces conformational changes and extension of the filaments, leading to the activation of the enzyme (PubMed:31586059, PubMed:32188856, PubMed:32523125). AdhE is inhibited in the presence of oxygen by metal-catalyzed oxidation (MCO) and by heat stress (PubMed:11917132, PubMed:19238259). The chaperone DnaK has a protective effect on AdhE activity under aerobic but not anaerobic conditions (PubMed:11917132). DnaK may protect AdhE and AdhE mutants against irreversible MCO damages and improve their ability to grow aerobically on ethanol (PubMed:11917132). IbpA and IbpB protect AdhE against thermal and oxidative inactivation during oxidative stress, providing that the enzyme remained soluble, and increase the efficiency of reactivation of heat-denatured AdhE by the DnaK system (PubMed:19238259). Acetaldehyde dehydrogenase activity is inhibited by guaiacol, which mimics an intermediate of ubiquinone synthesis (PubMed:10612730). Forms long filaments, called spirosomes (PubMed:31586059, PubMed:32188856, PubMed:32523125). Forms rod-like ultrastructures composed of 20-60 identical subunits (PubMed:1325457). Two monomers form a dimer in a head-to-head arm-crossing fashion through the ALDH domains (PubMed:31586059). Subsequently, two dimers form one helical pitch via the interaction of ADH domains in a tail-to-tail manner (PubMed:31586059, PubMed:32523125). These units are further assembled into spirosomes (PubMed:31586059, PubMed:32188856, PubMed:32523125). Formation of these spirosomes is required for activity (PubMed:31586059, PubMed:32188856, PubMed:32523125). Can be isolated in vitro in a wide range of oligomeric states (PubMed:31586059). Expression is about 10-fold higher during anaerobic than during aerobic growth (PubMed:10601216). Contains two transcriptional start sites, which are both functional. Both start sites are NarL repressible in the presence of nitrate and activited by RpoS. Fis is required only for transcriptional initiation from the upstream start site. Fnr can regulate expression from the downstream transcriptional start site only in the physical absence of the upstream region (PubMed:10601216). However, under all experimental conditions tested, only the upstream start site is active and acts as a silencer of downstream transcription (PubMed:10601216). Translation of the mRNA starting at the upstream site, but not the one starting atthe downstream site, requires RNase III (PubMed:10601216). Contains an N-terminal aldehyde dehydrogenase (ALDH) domain and a C-terminal iron-dependent alcohol dehydrogenase (ADH) domain, interconnected by a short linker (PubMed:31586059, PubMed:32188856). ALDH and ADH activities are topologically separated in the compact spirosome architecture (PubMed:31586059). Deletion mutant cannot grow aerobically in minimal media, is extremely sensitive to oxidative stress and shows morphologic defects that are associated with deficient septum formation (PubMed:12783863). In addition, mutant displays increased levels of internal peroxides and increased protein carbonyl content (PubMed:12783863). Both acetaldehyde dehydrogenase and alcohol dehydrogenase activities are thermolabile in temperature-sensitive mutants (PubMed:6752127). Has previously been proposed to have pyruvate formate-lyase (PFL) deactivase activity and to catalyze the quenching of the PFL radical in an Fe(2+), NAD and CoA dependent reaction (PubMed:2015910, PubMed:1325457). However, it was shown later that AdhE does not catalyze the deactivation of active PFL (PubMed:17280641). Inactivation of PFL is attributed to the CoA and Fe(II) present, which appear to increase the rate of deactivation (PubMed:17280641). In the N-terminal section; belongs to the aldehyde dehydrogenase family. In the C-terminal section; belongs to the iron-containing alcohol dehydrogenase family.