SIRT5_Af1_CobB: Eukaryotic, archaeal and prokaryotic group (class3) which includes human sirtuin SIRT5, Archaeoglobus fulgidus Sir2-Af1, and E. coli CobB; and are members of the SIR2 family of proteins, silent information regulator 2 (Sir2) enzymes which catalyze NAD+-dependent protein/histone deacetylation. Sir2 proteins have been shown to regulate gene silencing, DNA repair, metabolic enzymes, and life span. CobB is a bacterial sirtuin that deacetylates acetyl-CoA synthetase at an active site lysine to stimulate its enzymatic activity.