Catalyzes the deamination of various vicinal amino-alcohols to oxo compounds (PubMed:19762342). Allows this organism to utilize ethanolamine as the sole source of nitrogen and carbon in the presence of external vitamin B12. It is spontaneously inactivated by its substrate and reactivated by EutA (PubMed:15466038). ethanolamine = acetaldehyde + NH4(+) Binds 1 AdoCbl between the large and small subunits, with 6 cofactors per holoenzyme. Inhibited by 5-adeninylpentylcobalamin (AdePeCbl), a cofactor analog (PubMed:19762342). Irreversibly inhibited during catalysis by cleavage of the Co-C bond of the cobalamin coenzyme (Probable) (PubMed:19762342). Reactivated by EutA, which probably involves an ATP-dependent cobalamin exchange (PubMed:15466038). Amine and polyamine degradation; ethanolamine degradation. The basic unit is a heterodimer which dimerizes to form tetramers (PubMed:20519496, PubMed:21142024, PubMed:29797764, PubMed:19762342). The heterotetramers trimerize; 6 large subunits form a core ring with 6 small subunits projecting outwards (Probable). When grown in ethanolamine and adenosylcobalamin (AdoCbl) (at protein level). Note this experiment was done in strain JM109, which expresses the eut operon. Belongs to the EutB family. In strain MG1655 the eut operon is interrupted by the CPZ-55 prophage, encoding 9 genes situated between eutA and eutB, which are translated in the other direction. CPZ-55 may prevent expression of the eut operon in strain MG1655. Strain W3110 does not have this prophage element and should be able to express the operon.