2.3.1.280 Mg2+ the enzyme requires a divalent metal ion for activity. It exhibits a preference for Ni2+ followed by Mn2+ and very poor activity with Mg2+ 749881 2.3.1.280 Mn2+ the enzyme requires a divalent metal ion for activity. It exhibits a preference for Ni2+ followed by Mn2+ and very poor activity with Mg2+ 749881 2.3.1.280 Ni2+ the enzyme requires a divalent metal ion for activity. It exhibits a preference for Ni2+ followed by Mn2+ and very poor activity with Mg2+ 749881