<p>ATP:cob(I)alamin (or ATP:corrinoid) adenosyltransferases (<db_xref db="EC" dbkey="2.5.1.17"/>), catalyse the conversion of cobalamin (vitamin B12) into its coenzyme form, adenosylcobalamin (coenzyme B12) [<cite idref="PUB00035324"/>]. Adenosylcobalamin (AdoCbl) is required for the ativity of certain enzymes. AdoCbl contains an adenosyl moiety liganded to the cobalt ion of cobalamin via a covalent Co-C bond, and its synthesis is unique to certain prokaryotes. ATP:cob(I)alamin adenosyltransferases are classed into three groups: CobA-type [<cite idref="PUB00035323"/>], EutT-type [<cite idref="PUB00015064"/>] and PduO-type [<cite idref="PUB00013593"/>]. Each of the three enzyme types appears to be specialised for particular AdoCbl-dependent enzymes or for the de novo synthesis AdoCbl. PduO and EutT are distantly related, sharing short conserved motifs, while CobA is evolutionarily unrelated and is an example of convergent evolution. </p><p>This entry represents EutT- and PduO-type ATP:cob(I)alamin adenosyltransferases. PduO functions to convert cobalamin to AdoCbl for 1,2-propanediol degradation [<cite idref="PUB00006386"/>], while EutT produces AdoCbl for ethanolamine utilisation [<cite idref="PUB00035325"/>]. </p> Adenosylcobalamin biosynthesis, ATP:cob(I)alamin adenosyltransferase, EutT/PduO type