2.3.1.286 Mg2+ 1 mM used in assay conditions 2.3.1.286 Zn2+ contains zinc 2.3.1.286 Zn2+ contains Zn2+ 2.3.1.286 Zn2+ the small domain contains a structural zinc ion 2.3.1.286 Zn2+ the small domain of the enzyme contains a three-stranded zinc ribbon motif. No exogenous added Zn ions are needed for in vitro deacetylase and nicotinamide-NAD+ exchange activity