NAD-dependent lysine deacetylase that specifically removes acetyl groups on target proteins. Also acts as a protein-lysine deacylase by mediating protein desuccinylation and de-2-hydroxyisobutyrylation. Modulates the activities of several proteins which are inactive in their acylated form (By similarity). Activates the enzyme acetyl-CoA synthetase (acs) by deacetylating 'Lys-609' in the inactive, acetylated form of the enzyme (PubMed:12493915, PubMed:20889757, PubMed:12700259). May also modulate the activity of other propionyl-adenosine monophosphate (AMP)-forming enzymes such as propionate--CoA ligase (prpE) (PubMed:12493915, PubMed:12700259). Overexpression compensates for a cobT deletion, suggesting it may have N(1)-alpha-phosphoribosyltransferase activity; alternatively this protein may stimulate synthesis of an enzyme with the CobT activity (PubMed:9822644). H2O + N(6)-acetyl-L-lysyl-[protein] + NAD(+) = 2''-O-acetyl-ADP-D-ribose + L-lysyl-[protein] + nicotinamide H2O + N(6)-succinyl-L-lysyl-[protein] + NAD(+) = 2''-O-succinyl-ADP-D-ribose + L-lysyl-[protein] + nicotinamide H2O + N(6)-(2-hydroxyisobutanoyl)-L-lysyl-[protein] + NAD(+) = 2''-O-(2-hydroxyisobutanoyl)-ADP-D-ribose + L-lysyl-[protein] + nicotinamide Binds 1 zinc ion per subunit. Both isoforms are monomers (PubMed:20889757). Most expressed in mid- to late-log growth phases (at protein level) (PubMed:20889757). Has 3 promoters, P1 (upstream of nagK) gives rise to a nagK-cobB transcript, P2 (within the nagK coding region) gives rise to a transcript able to generate both CobB isoforms, while P3 (nucleotide 44 of the long isoform) can only give rise to the CobB-Short isoform (PubMed:20889757). 2 residues (Tyr-92 and Arg-95) present in a large hydrophobic pocket are probably involved in substrate specificity. They are important for desuccinylation activity, but dispensable for deacetylation activity. Single mutant grows on cobinamide (CBI), CBI plus 5,6-dimethylbenzimidazole (DMB) and cobalamin (CBL); double cobB-cobT deletion mutants do not grow on CBI plus DMB (PubMed:8206834). Single mutant does not grow on propionate (PubMed:8955330). Acetyl-CoA synthetase (acs) accumulates in an inactive, acetylated form (PubMed:12493915). Considerably decreased growth on 1,2-propanediol, cells do not excrete more propanediol than wild-type (PubMed:12700259). Originally isolated genetically as functioning in cobalamin biosynthesis and in propionate catabolism (PubMed:8206834, PubMed:8955330). The less prevalent isoform. 5- to 20-fold higher levels of this protein are seen in rich and minimal media. Belongs to the sirtuin family. Class III subfamily. Truncated N-terminus.